Human Energy Expenditure

Human Energy Expenditure

R. PASSMORE AND J. V. G. A. DURNIN

Fro-m the Department of Physiology, University of Edinburgh, Edinburgh, Scotland and the Instittite of Physiology, University of Glasgow, Glasgow, Scotland

HYSIOLOGICAL STUDY of man’s food needs and capacity for physical work be- gan on a systematic basis about seventy years ago. Following upon Atwater’s classic experiments with a human calorimeter at the end of the last century,

the validity of using rates of oxygen consumption as the basis for measuring energy expenditure (indirect calorimetry) was firmly established. Throughout this early period rates of energy expenditure during a variety of human activities were recorded. Recently there has been a renewal of interest in such measurements. This is in part due to the development of apparatus which can be conveniently applied under many industrial conditions, where it had not hitherto been practicable to use the more cumbersome apparatus designed for laboratory studies. Also, methods of work in many industries and in agriculture have changed markedly. Machines increasingly do the work formerly done by manual labor. This change is more noticeable in the highly industrialized coun.tries, but it is spreading throughout the world. Much of ‘heavy’ industry now consists in controlling large sources of mechanical power by means of levers and switches and the work for the human operator is often ‘light.’ Further, with increased productiveness there has been a shortening of the working week. There is now time and opportunity for recreations on a scale altogether different from fifty years ago. Many recreations demand much expenditure of physical energy and a wage earner may use his muscles more in his leisure time than during his earning hours. These factors call for new assessments of human energy expenditure,

Indirect calorimetry enables the energy expended to be determined while a de& nite activity is undertaken for a limited period of time, usually measured in minutes. More information is necessa.ry to assess the energy expenditure in daily life. This energy has, of course, to be provided by the food, if health and activity are to be maintained. In the past most assessments of total energy needs have been made from dietary studies. This was the method used by Voit, Atwater and others, who first stated the energy expenditure of a variety of occupations, after analyzing records of the diets consumed by persons of known employment. The method is open to the theoretical objection that it assumes that the diets consumed provide exactly enough energy with no surplus or deficiency. It provides no direct yardstick of requirement. Indeed in the East and elsewhere large numbers of people certainly have an insufi- ciency of food for health and activity, whereas the high incidence of obesity in West- ern countries shows that many consume regularly an excess of food over their physical requirements. There is a real difficulty in converting the results of dietary surveys into tables of food requirements. Further, dietary surveys are always difficult and expensive to carry out. This particularly applies to individual surveys, which provide so much more inform.ation than the less precise family surveys.

An alternative assessment of daily energy expenditure may be made by recording the time spent in each of the various daily activities and measuring by indirect calorimetry the metabolic cost of these. In this way a record of calorie expenditure through-

802 R. PASSMORE AND J. V. G. A. DURNIN Vodzcnae 35

out the 24 hours can be drawn up. Orr and Leitch (108) in their revieiv in 1938 give such daily estimates for several occupations. These are, however, for the most part illustrative only and based on limited physiological measurements. The amount of data at that time was limited to some extent owing to the practical difficulties of determining oxygen consumption with the Douglas bag under industrial and domestic conditions. The development at the Max-Planck-Institut fiir Arbeitsphysiologie (80, 103) of a light portable respirometer, which measured the volume of the expired air directly, and simultaneously diverted a small fraction (0.3-0.6%) into a rubber bladder for subsequent analysis, greatly facilitated indirect calorimetry+ This in- strument, which weighs less than 4 kg. and can be worn on the back like a haver- sack, has made investigations practicable under a great variety of conditions,

With this new aid to indirect calorimetry the Dortmund workers (87) ca+rried out a survey throughout German industry during World War II. They made observations only on persons at work in the factories and the mines, but, by making as- sumptions for energy expenditure outside working time, they expanded their results and expressed them in terms of daily energy requirements. Many recreations involve heavy muscular work and energy expenditure may vary widely from person to person. Soci,al circumstances determine in part the opportunity for physical recreations. In peace time, at least, any proper assessment of total energy expenditure must include considerations of activities both at work and at leisure, in the factory and in the home. Four surveys have been carried out in Britain in which overall energy expenditure was measured by a combination of indirect calorimetry and a complete recording of the pattern of daily activities. The first (III) was a pilot study of a group of students who led. a life arbitrarily restricted within the laboratory. The second (49) studied coal face miners and colliery clerks; and in the other two (132, 39) the subjects were military cadets undergoing intensive training. In all these British and German surveys the number of measurements made by indirect calorimetry number over 2000, Xn addition there are numerous other measurements in the literature over the last 50 years. Our purpose here is to present, in the form of tables, samples from these results. These tables by no means include all the published work in this field, but are a selection which we hope will enable others interested in energy expenditure to make assessments under field conditions.

In estimating the expenditure of energy of any individual, it is our experience that larger errors are likely to arise from a failure to determine correctly the length of time spent in any activity rather than in any assessment of the metabolic cost of that activity. For instance, if a man walks to and from his work every day, it is essential to know how long he spends on the journey. When compared Gth his other activities, the exacl energy cost of the walking may be comparatively unimportant. Further, one measurement of such an activity is only strictly applicable to the walking while the measurement is being made. An accurate value for an individual’r; walking, in general, necessitates several estimations under a variety of environmental conditions. For these reasons, a value derived from an informative table may introduce only a small error. Field experience is needed for the proper use of such tables; but if their use is combined with accurate determinations of the time spent in ea.& ztctivity, which can be done by unskilled assistants with no laboratory equipment, the increase in error will be of little importance.

With t.he intelligent use of these tables we consider that estimates of individual daily energy expenditure, accurate to within IO per cent, can be made with the help of very few additional metabolic measurements.

October 1955 HUMAN ENERGY EXPENDITURE 803

To a certain extent the tables are comparable to tables giving the nutritive values of food. In such tables the figures given are based on one or more analyses of individual samples of foods. Yet they are used in calculating the energy value of mixed diets and provide useful information of a reasonable degree of accuracy (135). Cer- tain foods, notably milk and meat, vary widely in chemical composition from sample to sample and, if these form a large proportion of the diet, analyses of the actual foods consumed are desirable. Similarly in estimations of energy expenditure, if one activity predominates, in a daily routine, actual measurements of the cost of this activity will be necessary.

How to express the results has presented a problem. We have decided to give all figures as kilocalories per minute (Cal/min.) of gross energy expenditure. Values expressed as Calories per hour are liable to misinterpretation, for very few activities are carried out at a steady rate over such a long period. Both work and play take place more commonly in periods of varying intensity lasting a few minutes only and interspersed with rest pauses. The argument as to whether gross or net values are best used is more complex. Most writers, including the Dortmund School, give their results in net calories after deducting a value for basal or resting metabolism. In many instances, the basal rate has not been determined, but calculated from one of the standard prediction tables, This deduction seems an unnecessary procedure. If allowances are made for the subject’s weight, gross values are more directly useful. That it is wrong to deduct from the energy expenditure of work a value for the resting metabolism-before work has been suggested by Wachholder (Izg), on the ground that the exercise itself may have an effect on the resting level of metabolism. Ac- cordingly in the tables, we have added, where necessary to an author’s figure an esti- mated value for the BMR, in order to make all the figures comparable. Variations in basal metabolism from person to person are small in comparison with total energy expenditure and no great error in any individual figure has been introduced. Most of the figures reported have been determined at varying times of day unrelated to meals. Accordingly, they include the values for the specific dynamic action (S.D.A.) of food. The S.D.A. of food is very variable and it is uncertain to what extent, if any, the energy involved can be utilized for muscular work (107, 96, 37). Attempts to allow for the S.D.A. only give a false impression of accuracy. In some papers only data for oxygen consumption have been given. These have been converted into Calories using from 4.8 to 5.0 as the calorie equivalent of oxygen. Some data are expressed in Cal/sq.m. and these have been converted assuming a surface area of 1.80 sq.m., unless the exact value has been given.

We apologize to those authors who find their results quoted in a form different from that in their original presentation. Had these liberties not been taken, the tables would have been much more awkward and cumbersome.

SLEEP

Most people spend about one-third of a normal day in bed asleep and the energy used in this way may account for one-tenth to one-quarter of the daily energy expenditure.

The main problem in assessing the metabolism during sleep is how accurately it can be assessed from the basal metabolism. Several series of experiments have given conflicting results on this point, and it may help to understand the reasons for these if we consider the manner of sleep. Kleitman (78) divides adults into three groups ac- cording to the manner in which they rest. 0) Those who have absolute rest for about

804 R. PASSMORE AND J. V. G. A. DURNIN Vd?me 3.5

3 hours after the onset of sleep, followed by short alternating periods of relative and absolute rest. b) Those enjoying absolute rest throughout the night. C) People whose sleep is broken into many periods of relative rest. No data were given for the per- centages in each group. Johnson and Weigand (66) showed that during sleep varying degrees of muscular movements of the limbs take place, although the total time spent in gross movement appears to be quite small (79, 51). These experiments show that sleep may vary markedly between individuals and, in any case, rarely means lying for 8 hours, motionless and flat on one’s back.

In the direct comparisons of the metabolism when asleep and awake, Delcourt- Bernard and Mayer (29) observed a decrease in the basal metabolic rate during short periods of sleep in three subjects, no change in a fourth, and an increase in a fifth subject. An interesting point, which casts doubt on the value of basal metaboli.sm studies, is that they found the dorsal decubitus position was not necessarily the position where gaseous exchanges were lowest; in some individuals there was a lower metabolism when they lay on their sides, semi-flexed, or even curled up. This may account partly for lower than basal values being recorded during sleep.

In a study of three healthy young subjects, Grollman (61) found exactly the same oxygen consumption when they were asleep as when they were awake a few minutes later; i.e. sleep per se did not affect the oxygen consumption. He found, however, that during the night the oxygen consumption decreased gradually to a minimum about 5 to 6 hours after the onset of sleep, and this minimum was about ro per cent below the basal rates.

This lack of any appreciable difference between the metabolism while asleep and while resting in the waking state agrees with the findings of Loewy (90), Johans- son (65) and Delcourt-Bernard and Mayer (29). On the other hand Mason and Benedict (100) found a decrease of about IO per cent below basal levels in seven Indian women when asleep. The basal metabolism of these women was measured early in the morning; their metabolism was then measured a few minutes later when t.hey had fallen asleep again, and they were later awakened and a third estimate obtained, The apparatus and experimental methods of Grollman, and Benedict and 311ason are so similar that it is difficult to explain the contradictory findings.

Mason and Benedict (100) estimate that the average of all experiments previous to 1934 on the effect of sleep on basal metabolism indicates a decrease of about 7 per cent (8, II, 61, 65, 94, 104, 113). However, almost without exception, these experiments have been on fasting subjects and the majority have been short-period experiments. Most authorities agree that the depth of sleep varies throughout the night so it seems inaccurate to say that the metabolic cost of sleep is TO per cenf. lower than the basal metabolism.

In summary there appears to be no doubt that in certain circumstances, and particularly when fasting, the metabolism when asleep may fall below the B&K HojYever, at the beginning of a normal night’s sleep, owing to the effect of the last meal, the metabolism may be above the basal level. These two factors tend to cancel each other out and the BMR is certainly not far from the average rate of energy ex- I)enditure throughout a normal night’s sleep. A departure of IO per cent above or below the normal basal level involves an error of only some 50 Cal. throughout; a Ilight’s sleep, which is a very small proportion of the total q-hour expenditure. Thus the BMR can be taken as a measure of the metabolic rate when in bed, asleep or iawake.

It is not one of the purposes of this paper to review the literature on vzristions

%JKE I. ICNERGY EXPENDITURE CARRYING OUT PERSONAL NECESSITIES

Ref. Subj.

49

3.5

rrr

39 x17

rr7

Lb?. of I2

Av. of 7

C.G.D.

Bob T. Av. of 3

*4v. of 5 AL of 9

Av. of 4 L4V. of 6

Age St% Wt., kg. Activity Cal/min.

S-r I 9-10

28

2s

43-55

2 r-23

18-20

20-25

20-25

5 M. M

34

35 58

68

70

73

69 62

62

Dressing and undressing Dressing and undressing Washing hands and face, brush-

ing hair Washing, and dressing Washing, dressing and undress-

ing Dressing, washing and shaving Dressing Washing and shaving Dressing

2.3

3.5

2-S

2.6 3.3

3.8 480 2.6 3.0

in basal metabolism. Fleisch (45) and Robertson and Reid (I 18) give standards from which the basal metabolism. may be easily caIculated.

PERSONAL NIxESSITIES

Everyone spends some part of the day in carrying out personal necessities; this includes getting up, going to bed, washing, shaving etc. In a schematic repre- sentation of how a man may spend his day Lehmann (8G) allows I hour for ‘persiinlich Bediirfrisse.’ 130th the tempo and the t,otal time spent in these activites naturally vary a great deal. ‘.I’able I records measurements which have been made on various subjects.

This section deals with the energy cost of all methods of locomotion, w&ing,

climbing and running. Skiin,, <J mountain climbing and bicycling are discussed under RECRE.~TI~X~.

Walking is the commonest form of exercise and, together with climbing stairs, may be for many people the only break in an otherwise sedentary life. Predicting the energy cost of walking involves many uncertainties. In everyday life, people walk very differently, First of all, the speed may vary markedly, not only between individuals but also in the same individual on differing occasions and even within the course of the same jvalk. Many go at a uniform speed only when walking for some specific purpose, such as going to work, or to catch a bus or t,rain; in a society well equipped with both public and private transport these occasions involve exercise last.ing only a few minutes. A recreational walk, a constitutional stroll, or a shopping expedition may last for a much longer period and the pace may vary greatly. The ground covered may also change, not only in type of surface, smooth or rough, but also in gradient; it may be level, uphill or downhill all the way, but sometimes is a mixture of all three. The coefficient of variation in the metabolic cost of individuals walking at constant speed is of the order of 15 per cent (96). This individual variation may be much less than variations clue to changes in speed and gradient.

Walking on the Level. From the latter part of the 19th century up to the present day, many measurements have been made of the energy expenditure of walking on the level. The results have usually been independent of whether the subject wa.lk,ed on all outdoor or indoor track or on a treadmill. Figure I is a composite graph from data recorded of ivalking at varying speeds in England (33), in Austria (IS>, in the United States (12), in Germany (4) and in Italy (c$). The weights of the subjects were

So6

f-9

-8

R, PASSMORE AND J. V. G. A. DURNIN

i 2 3 4 5 6 7 8 9 IO

FIG. I. Energy expenditure walking on the level at different speeds. Abler and Herbst (4) * z Benedict and Murschhauscr (I 2) -+, Brezina and Holmer (15) 1, Douglas and Haldanc (33) X, Margaria (~$3) 0.

between 60 and 75 kg. For the present purpose so good is the agreement between the data from these five laboratories that tabulation of the many other results seems unnecessary.

Over the range 3 to 6.5 km/hr. (approximately 2-4 mph) energy expenditure is linearly proportional to speed and the relationship is expressed by the equation

c = 0.w + 0.5 ( > I

where C = energy expenditure in Cal/min. and V = speed in km/hr. Figure I shows that at higher speeds, energy expenditure increases at faster rates.

The effects of weight, age, sex and race on walking on the level at constant speed have been investigated (96). Measure.ments were made on 50 persons walking untler standard conditions at 4.8 km/hr. (3 mph). Statistical analysis showed that age, sex and race had no significant effect on the metabolic cost of the work. The energy expenditure was found to be proportional to body weight. The regression equation was:

c = 0.047w + 1.02 ( > 2

where IV is the gross weight in kilograms. A systematic study of the combined el- fects of varying speed and varying weight has not been made. Table 2 however has been drawn up by calculations from eqz&ions I and 2. The figures should predict energy expenditure with an accuracy of about &IS per cent for any individual. If walking occupies less than I hour a day the total error involved in using the table in an assessment of energy expenditure over 24 hours will not be great. If walking plays a larger part in the daily life of an individual, then measurements of the metabolic cost should be made.

Walking on an Incline. Grade walking has also been the subject of many iw vestigations, both on a treadmill and outdoors. Most of the outdoor studies have t-)ee~

0ct0ber q)yj HUMAN ENERGY EXPENDITURE 807

TABLE 2. RELATIONSHIP BETWEEN ENERGY EXPENDITURE (Cal/min.) AND SPEED OF WALKZKG

(mph) AND GROSS BODY WEIGHT (lb.) . ..-m-w-- -IIII-- - _. _ .-.m-_-___1_-- --*-...-----

I Weight, lb.

Speed mph -- 80 100 120 IqO 160 II30 200

-- -.- ----p--

2.0 I-9 2.2 2.6 2.9 3*2 3.5 3.8 24 293 2.7 3-r 3.5 3.8 4*2 4*5 3-O 2.7 3.1 3-6 4** 4.4 4.8 5.3 3-5 3*I 3.6 462 4.6 50 s-4 6.1

4.0 3-s 4-r 4.7 S-2 S-8 6.4 7-O

done either at high altitudes or using the old Zuntz apparatus which was both heavy

and clumsy for the subject. A most comprehensive treadmill study was carried out by NlIargaria (98). Figure 2 has been drawn from his data and shows the energy cost of walking up gradients of o, 5, 15 and 25 per cent plotted against rate of linear ascent: in kilometers per hour for a subject of 70 kg wt. The effect of downhill gradients have not been so systematically studied. Margaria found that going down a slope of I in

IO at varying speeds involved an energy expenditure of up to 25 per cent less than walking on the level. On very steep declines and especially at slow speeds energy expenditure mav be appreciably more than when walking on the level.

That these results have some general applicability is shown by the observations of Keys, Brozek? Henschel, Mickelson and Taylor (76). They found the mean rate of energy expenditure by 16 healthy subjects, average weight 70.6 kg., walking at 5.6 km/hr. up a IO per cent incline to be 8.9 Cal/mm. This point is marked by a cross in figure 2 and falls aImost midway between the lines for the 5 and 15 per cent slopes.

Running on the Level. Apart from athletes, it is unlikely that running will account for more than a tiny fraction of the total energy metabolism. Margaria (98) snd Ogasawara (106) have shown that the energy expenditure may vary from arou& 9 Cal/min. at a speed of 7 km/hr. t.o as much as 20 Cal/min. at speeds of 12 km/In. and over. Variations in the calorie cost of running are great and depend on the degree of training and efficiency of the subject.

Effect of Different Surfaces. The type of surface may have a slight effect on the energy cost of walking. However, unless the surface is markedly rough, the effect will probably not exceed IO per cent more than walking on a flat surface. Table 3 shows the increase in energy caused by rough uneven surfaces of varying texture (53) < ’

Climbing Stairs and Ladders. Several measurements have been made on stair climbing (13,35,g3, III), some of them on women. Table 4 presents some of the data. The values are for the combined motions of going up and down ordinary household stairs; descending involves only about one-third of the energy used in going upstairs. The values give this activity the appearance of moderately heavy work, and it is a common complaint of many housewives that the stairs are very tiring. However, as Schneider and Karpovich (I 21) have pointed out, to ascend a staircase, which in the ordinary house has about fifteen zo-cm. steps in each storey, representing a vertical distance of about 3 meters, requires less than 2.5 Cal. for a 6o-kg. person. Addition of the cost of descending brings the total to about 3 Cal. Even going up and down stairs IO times in the day hardly adds a significant amount to the total metabolism. The table also gives some values for climbing ladders with and without th.e addition c,f loads (86).

80X 31. PASSMORE AND I’. V. G. A. D’URNPhT

FIG. 2. Energy expenditure walking uphill at different speeds. Data frond Margaria (98), except for one point -i-, which is an average figure for x6 subjec-ts from Keys et al. (76) l

km/hr I 2 3 4 5 6 7 ,8 ,9

b Y

RECREATIONS

Several hundred measurements of energy expenditure covering a varietv of rt;‘cru- ;%tions have been made. Tables 5 to 8 give a selection of results. Yet the/are by no means complete and the energy cost of many types of games has not to our knowledge ken measured. Table 5 deals with the children’s activities, table 6 with light indoor rc~reations, table 7 with moderately energetic games, dancing and outdoor activities, ttrzd table 8 lvith heavy sports, such as swimming, climbing and skiing. So Inany factors may have a large influence on the energy expenditure during sports and recrea-

- t ions that comments on some individual results are necessary. Table 5 contains data for few of the vigorous activities that go to make up a

child’s life. When ‘playing in the school playground’ (28), the children were impeded by a Douglas bag on their backs; the children were Asiatics below European stand- ;trds of weight and the figures almost certainly do not represent typical children’s play. The cycling was done on an ergometer. The very limited data available at the moment are clearly insufficient to assess the energy expenditure of a normal active c*hild’s manifold activities.

In table 6, the data on young men playing cards were obtained by Douglas (32) (luring two investigations in connection with the ventilation required for gasproof ;l,ir raid sheiters. He determined the rate of vitiation of the air in a sealed compart- r w tt below decks in a ship and in the dead end of a London underground railway

October 1955 HUMAN ENERGY EXPENDITURE

TABLES. ENERGYEXPENDITURE WALKINGONDU-FERENTSURFACE~ (58)

Su&ect, age 23, wt. 69 kg., ht. 175 cm.

Nature of Surface Speed, km/h. Cal/min.

Asphalt road 54 5-h Grass track 56 6.2

Potato furrows s-4 6.9 Stubble field w 6.8 Ploughed field 53 7-6

TABLE 4. ENERGY EXPENDITURE,GOINGUP ANDDOWN STAIRS Ahm CLIMBING LADDERS --

Up and Down Stairs Without Load, Ht. of Each Stair, 15.2 cm.

--

Ref.

--

111

IX1

35

Vertical speed

m/min. --

14.8 17.6

Not

stated

Weight of subject, kg.

59 1 65 1 69 1 75 1 79 1 80 j 83 ( 84

6.0

8-s 9-3

II.8

8.0

- - - I . -II - .

--- -- Climbing Ladder (86), Ht. of

Each Step, 17 cm.

70”

90*

Ver tica speed,

m/min.

9-I

11.1

II.9

1 Load

.---

0

20

50

0

20

50 0

20

$0

Cal/ min.

9-o 11.3

17.1

II.5

14.6

25.4

system. Naval and military personnel of good physique were used. Each experiment lasted up to 3 hours and the men were allowed to sing and play cards, but had to remain seated. Seven experiments were done and up to 132 men acted as subjects in each. Oxygen consumption per man varied from 445 to 535 ml/min. in these experiments. This corresponds to a rate of energy expenditure of from 2.2 to 2.6 Cal/min.

The figures in table 7 are often subject to wide variations. In canoeing, for instance, the effects of wind and current may increase the energy cost by as much as 300 per cent. The figures quoted (133) are for moderately skilled men in favorable knvironmental conditions. The figures for riding (50) showed remarkably good agreement between the three riders, even though the experiments were done on different days. Other data (116, I 17) for riding by cavalry and horse artillerymen are summarized in tables 32 and 34.

The energy cost of bicycling varies greatly with speed. Despite the many studies on bicycle ergometers in the laboratory, only Zuntz (137) in 1899 appears to have made a systematic study of the effect of speed on energy expenditure during bicycling on the road. The other figures given in table 7 are for subjects bicycling at their own selected speed. Asmussen (2) has studied the energy expenditure of a subject bicycling at 8.6 km/hr. and at 135 half pedal revolutions/min. on a treadmill, the slope of which could be adjusted. Going uphill, energy expenditure in Calories per minute (C) was equated with work done in kilograms per minute (E) by the equation

C = 10.2E

1000 + 2.25 (3)

810

Ref. I26

124 124 124 I26

8;

ws I2 g-12 F 125 7 IO-II M 126 13 g-11 F

28 25 IO M 28 25 =4 M

124 6 7-8 M 124 6 g-11 M 124 IO I 2-14 M 85 II 13-14 M+F

R. PASSMORE AND J. V. G. A. DURNPN Vd21?m3 35

TABLE 5. ENERGY EXPENDITUIU DURING CHILDREN'S RECREATIQKS

Av. x0. of

Subjects I2

6

6

IO

IO

5

Age g-x I 7-8 g-x I

12-14

6-9 13-14

St% F M M M M

M+F

Wt., kg.

33 22

29 41 37 41

34 35 35 24 32 22

29 41 40

Sport or Recreation Energy Cost)

Cal/min . Sitting, listening to radio Sitting, playing at puzzles Sitting, playing at puzzles Sitting, playing at puzzles Sitting, singing Playing balalaika, mandolin and

klavier Standing, drawing Standing, drawing Standing, singing Playing, school playground Playing, school playground Cycling Cycling Cycling Carpentry

for rates of work varying from 200 to 1600 kg.m/min. Going downhill, leg movements were reversed and the relationship between C and E over the same range espresscd by the formula

c = XE + 2.37 IO00 (4)

The ratio of the cost of positive to negative work is given by the ratio of the slopes of these two lines and in this case was 7.4. (The problem of the nature of negative work is a fascinating one but outside the scope of this review. Interesting experiments with full discussion are recorded by Abbott, Bigland and Ritchie, ref. I). The energy expenditure during bicycling is in part dependent on the size of the tires. Dill, Seed and Marzulli (30) have recently shown that the large tires now in fashion on Ameri- can bicycles necessitate the expenditure of about I Cal/min. more than when bicycling at the same speed on a similar machine with traditional narrow tires.

The figures for gymnastics (74) are averages of many estimations on one man carrying out several types of exercise prescribed in a British Army training manual. The value for golf (49) was obtained by measuring the energy expenditure of a 9 handicap player continuously over two holes. The values for cricket (39) are based on measurements of the different activities involved in the game in conjunction with n time study during actual matches. They are thus an over-all estimate of the energy expenditure of batting, bowling and -fielding.

The figure for association football of 8.9 (range 6.0-12.0) Cal./min. is based on measurements while the men were actually in play with the ball. For 512 estixnate of overall expenditure during a game, an allowance for the times of relative inactivitjv I%Tould be necessary (see DAILY ENERGY EXPENDITURE RATES).

Most of the data for swimming give details of the number of strokes used and the distance covered per minute. Recreational swimming with different strokes, resting, floating and diving is usually fairly energetic and an over-all rate of energy expenditure of 6 to 7 Cal/min. is probably common. The figures for swimming given in table S are in general agreement with those of Karpovich and Millman (70). Swimming at: speeds greater than 50 m/min. may be very vigorous exercise, but the skill of the swimmer is an important factor.

elctober 1955 HUMAN ENERGY EXPENDITURE 8xX

Ref.

49 39 49

*34 35

111

III

=34 III

III

III

32 I27 =27 127 49 91

I27 91 41 41 91

127 49 49

I34 91 91 91 49

TABLE 6. ENERGY EXPENDITURE DURING LIGHT INDOOR RECREATIONS

Subjects 49 Sex Av. of 12 32 M Av. of 12 I9 M Av. of 16 34 M K.N. 24 M Be 44 F EViZTJ 21 M IUirt 21 M H.114. 25 M Iah 21 M Evan 21 M A listair 21 M Av. of 112 Young M

J.&t. 28

P.M-.

Av. of 5 26 M Av. of 7 38 h!t ILK 25 hz FL 50 M O.B. 28 h4 J.W. 67 h!I Av. of 3 33 hl

30 34

49

M M

M h;l M h!l

Wt., b 70

6Q 70 66 62

65 SO

82 64 82 80

76

62 70 62 68 62 62

63 60

65 58 65 69 64 64 64 67 71 64

Recreation Lying at ease Lying at ease Sitting at ease Sitting at ease Sitting, eating Sitting, listening to radio Sitting, listening to radio Sitting, writing Sitting, writing Sitting, playing cards Sitting, playing cards Sitting, playing cards Sitting, playing woodwind Sitting, playing horn Sitting, playing flute Sitting, playing accordion Sitting, playing piano Sitting, playing violin Sitting , playing cello Sitting, playing organ Sitting , playing organ Sitting, playing drums Sitting, playing drums Standing at ease Standing at ease Standing, drawing Standing, conducting orchestra Standing, playing trumpet Standing, playing double bass Playing with children

Energy Cost, Cal/min.

I-4 14 1.6 1.6

14 2.0

24

1.9 2.2

I-9 2.1

2.4 2.0

2.0

2.2 2.2

Q-5

2.7 2.6

3*2 395 490 4.2 I.7 I.9 2.3 2.;

2.1

2.5

3*5

DOMESTIC WORK

Domestic activities are varied and manifold. Table g shows a selection of a large number of measurements which have been made. Many-domestic tasks involve hard physical work. However, the work necessary and the amount of equipment and electrical power available are very different in many homes, and the total daily expenditure possibly varies more among housewives than in any other group. One systematic study has been made (35). It was carried out in wartime Germany on three housewives, who lived in homes with very limited equipment and each of whom was some- what obese.

Table 9 shows clearly that domestic work may be heavy. In times when food is scarce and a rationing system strictly enforced, the fact that many housewives may be doing hard physical work is often overl.ooked. In such circumstances further field studies might be desirable.

MENTAL WORK AND OFFICE WORK

The brain has a very high rate of oxygen utilization, about 3.5 ml/Ioo gm/min. (82). This amounts to nearly 50 ml/min. for the whole organ or roughly 20 per cent of the total oxygen uptake of the body at rest. That concentrated mental activity requires appreciable extra amounts of energy is a common assumption and some of the early investigators claimed that this was the case. However, in 1909 Benedict and Carpenter (IO) measured in a respiration calorimeter the heat production of 22

3x2 FL PASSMORE AND J. V. G. A. DUKNIN I wlkme j-5

Ref.

39 39

133

I33

50 50 50

=37

=37

I37

39

49

49

49 III

III

1r1

III

III

49

49 49

74

74

74 74

115 49

49

39

39

39

39

.39

Subjects

Av. of 3

AK of 3

Av. of 4

Av. of 4

Av. of 3

Av. of 3

Av. of 3

zuntz, L, Zuntz, L” Zmtz, L. Av. of IQ T.A. J.H. B.T. George EtUH3 .A listaiY George Av. of 3

W.B. G.B. GM.

G.C. 32 J.K. 29 Av. of 2 20

Av. of 6 19 Av. of 6 19 Av. of 6 I9 Av. of 7 I9

Age 19 I9

19

27

32 28 23 21

21

23 21

41

46

40

27

27 27 27

university students during a 3-hour examination and during a control period and stated that “the results ob t sined in these experiments do not indicate that me11ln1 effort has a positive influence on metabolic activity.” In 1933 Benedict and Benedict (9) demonstrated beyond any manner of doubt that mental work requires an insig- nificant additional expenditure of energy. They studied six subjects and oxygen consumption was determined by spirometry, the subjects wearing a large helmet and breathing through a closed circuit apparatus. Experimental periods were about rj minutes long; periods of repose and mental activity alternated on each day and were repeated on each subject for several days. The mental work consisted chiefly of arithmetic and involved multiplication of pairs of 2 digit figures. The metabolism rose from a mean of I .oo Cal/min. during repose to 1.04 Cal/mine during mental effort. The maximum rise for any one person was 0.06 Cal/min. The figure for repose approximated to the theoretical basal values for the subjects and the mean increase was only 4 per cent, This rise amounts to only 2.4 Cal/hr. Indeed only experienced workers using accurate apparatus under the most careful experimental conditions could have demonstrated such an increase satisfactorily. Other studies (;2 r, 22, 88,

Sex

M M M M M M M M M M M M M M M M M M M M M M M

wt., kg* 64

64 68 68

73

73

73 7=

7=

7=

69 57 67 68

69 80 76 69

77 55 6; 63 68

M 68 M 68 M 68 M 68 la 70 M 63 M 69 M 72 M 72 M 72 M 70

Recreation Driving a car Driving a motor cycle Canoeing, 2.5 mph Canoeing, 4.0 mph Horse riding, walk Horse riding, trot Horse riding, gallop Cycling (5.5 mph) Cycling (9.4 mph) Cycling (13.1 mph) Cycling (own pace) Cycling (own pace) Cycling (own pace) Cycling (own pace) Dancing, petronella Dancing, foxtrot Dancing, waltz Dancing, rumba Dancing, eightsome reel Gardening, weeding Gardening, weeding Gardening, digging Gymnastic exercises--

balancing exercises, abdominal exercises, trunk bending, arms swinging, 13 opping et c

Volley ball Bowls Golf Archery Cricket, fielding Cricket, bowling Cricket, batting Tennis

-I* 5 ;i.o

1P.L

8 .2

s-9 6 .6

s13

TABLE 8. EXEKGY EXPEND~TUKE DCJKING IIECKEATX~KS ~XV~LVIXG IEXKD EX~~;RCISE

Ktf.

117 88a 88a 8%~ 8th 88a 88a 88a

93 95 89 89 89 89 89 9 g:: 8;

89 89 39

rr7 38

<is

38 38

3s 3s

24

24

24 B.L.

Subj. Age

Av. of 4 23 S.R. 22

S.R. S.R.

J.L. 48 J.L.

G.L. 32 ii .Ii. 31 J.R. 21

J.B. 21

Av. of 2

Av. of 2

Lb. of 2

Av. of 2 19 Av, of 4 25 AK of 2

i I \ : . Of 2

Av. of 2

Lb. of 2

B.L.

nr.iv.

i1r.X.

wt., kg* 68 66

61

50 52 68 68

71 71 71 90 90 90 90 90 90 90 67 65 83

(3 Y

83 c3 ‘i

83 83 83

57

83

(- 3 s

5 7

6s c- ‘3

Sport or Recreation

Football, association Sculling at 51 m/min. Sculling at 69 m/min. Sculling at 97 m/mm. Sculling at 61 m/min. Sculling at 87 m/min. Sculling at 93 m/min. Sculling at 68 m/min. Swimming, breast stroke Swimming, back crawl Breast stroke, 20 yd/min. Breast stroke, 30 yd/min. Breast stroke, 40 yd/min. Back stroke 25 yd/min. Back stroke 30 yd/min. Back stroke 35 yd/min. Back stroke, 40 yd/min. Side stroke, 40 yd/min. Crawl, 45 yd/min. Crawl, 55 yd/min. I-laying squash rackets Cross country running Climbing

slope I in 5.7

5 kg load 1 o-kg. load 2o-kg. load

slope I in 4.7 s-kg. load

x o-kg. load zo-kg. load

Skiing, level hard snow, 6 km/hr. level hard snow, moderate speed

Walking on hard snow 6 km/hr. with snow shoes, soft

snow, 4 km/hr. Skiing


899 4-r 6.4

11.2 4.8 7.0

5, . 3

5 * 5 1r.o

x.5

,i -0

7.5

10.0

5 -0

‘I.0

C) . 0

II.0

IT .o

r I . j

14.0 10.2

10.6

10.7 JI.0

12.2

level hard snow, moderate speed 1 j ’ r) uphill hard snow, max speed TS.h

Walking, loose snow, zo-kg. load, 4 km/hr. 20.2

120) have given essentially the same result, but there is a great degree of individual variation. Eiff and Gijpfert (40) studied 57 persons. The average rise of metabolism on mental effort was 11.6 per cent, but differences in single experiments ranged from 3-56 to - 2x per cent. Electromyographic studies were carried out simultaneou+ snd the authors concluded that a rise in metabolism during mental work could be related to a corresponding rise in muscle tone.

In most of the papers quoted, mental work has entailed sitting still for long periods. When an estimate is required for the calorie output of mental effort, the value for energy expenditure when sitting still will give an accurate figure. However,

814 R. PASSMORE AND J. V. G. A. DURNIN tz701zknr e 35

Ref. Subj.

84 Av. of z 84 Av. of 2

I34 CN

134 CN

83 Av. of 4

35 Al 20 C.G.D. 35 Al 39 Av. of 5

III George

130 Av. of 3

35 Al 20 C.G.D. 35 Be 35 Al 35 Be

130 Av. of 3

49 Bob T. 35 Ha

1x7 Av. of IO

117 Av. of xo

35 HO

39 Av. of 5

35 Be 35 Ho

35 Al 49 Bob T. 49 Be 49 Al

49

49

49 Be 49 Al 49 Ho 49 Al

HO AZ

TABLE 9. ENERGY E~P~DI~RE DURING DOMESTIC worn

Age 22

22

22

43 28

43 20

23

31

43 28

44

43 44

31 28

$5 24

24

55 19

44

55

43 28

44

43

55

43

44

43

55

43

sex F F F F F F M F M M F F MI F F F F M F M M F M F F

F M F F

F F

F F F F

wt., kg* so 50 44

44

50 84

58 84 71

69 48

$4

58 6.5 84 65 48 68 80

GI

61

80

67

65 SO

84 68 6s 84

80

84

6s

c4 s

80

84

most types of mental and clerical work . 1 1 l 1 . * l

mvolve some pnyslcar actlvlty, such as writing, opening and shutting books and drawers, walking across a room to get a, book or paper. We have made an extensive investigation on IO male clerks during normal work in a colliery office (49). Energy expenditure wa$s measured over XO- minute periods while entering up ledgers, completing registers, issuing pay slips etc., and included occasional journeys across a small office to get forms, books etc. Table IO shows these results. The mean values when sitting and stand.ing at work are 50 and 70 per cent respectively above predicted basal met,abolic rates. By ahoy- ing an increase of these amounts over the predicted basal. metabolic rate, the assess~ ment of rates of energy expenditure of ofice workers would probably not be greatly in error. Normal office work does not involve great energy expenditure. Some clerks, however, spend much time in walking bet,ween various offices, and, in these instances, allowances for this increased physical work would have to be made. “RAle TO An

Activity

Sewing, 30 stitches/mine Knitting, 23 stitches/min. Hand sewing Sewing with machine Sweeping floors Simple work sitting Brushing boots Washing sma,ll clothes Polishing Peeling potatoes Scrubbing standing Stirring Cleaning windows Washing small clothes Bringing in the wash Kneading dough Scrubbing, kneeling Getting in coals Scrubbi ng floors Cleaning windows Tidying beds Mopping Ironing Wringing the wash by hand Taking out and hanging out the

wash Polishing floor Breaking firewood Beating carpets and mats Taking and hanging out the wash-

ing Bed making, bed stripping Clearing floor ‘kneeling and Exnd-

ing’ Putting washing through mangle Scrubbing Beating and brushing carpets Putting washing through mangle

October I955 HUMAN ENERGY EXPENDITURE 815

TABLE IO. ENERGY EXPENDITURE DURING CLERICAL WORK, Cal/miIL

Misc. Of- fice ‘Work No. of

(49) * Observ. Min. Max. Mean TYPk (99) t Min. Max. Meau

Sitting 36 1.28 1.82 1.6 Mechanical 30 words/min. I. 26 I .47 x.39 40 words/min. I. 39 I. 57 I .48

Standing 45 1.54 ~47 x.8 Electrical 30 words/min. 1.13 1.19 1.16

* Subjects, IO men, wt. 55-72 kg. t Subjects, 6 women, wt. 44-52 kg.

40 words/min. I .25 1.39 1.31

shows the results of an Italian study (gg) on six young women using an ordinary mechanical and also an electrical typewriter. Measurements were made over several ro-minute periods. When typing on a mechanical typewriter at about 30 words/ min., there was an increase of 45 per cent over the resting metabolism, and at about 40 words/min., the increase was 55 per cent. With the electrical machine, the re- spective values were approximately 20 and 30 per cent.

The metabolic cost of the mental work of school children has been measured in Moscow in 1935 (85). During a variety of lessons, 38 children, aged x3 to 14 years, mean weight 41 kg., expended energy at a mean rate of 1.05 Cal/min. and 3g children aged g to ro years, mean weight 28 kg., at 0.83 Cal/min.

LIGHT INDUSTRIES

The variety of the different tasks, which may be described as light industry, is so great that it is impracticable to try either to describe or classify them exhaustively and figures for the metabolic cost of such work can only be very broadly illustrative. Tables II to 14 contain a selection of data from four good studies carried out under conditions which were probably fairly representative of work in Europe between 1916 and 1950. Turner (128) measured the energy expenditure on 302 persons engaged in light engineering at a plastic and ebonite moulding factory, an accumulator factory and a government; training center in the neighborhood of Manchester just after World War II. Table I I is a selection from his results. Greenwood, Hodson and Tebb (60) studied women working in a munition factory during the first world war. Table 13 contains data from a comprehensive investigation in Germany during World War II (87) and table 14 from an excellent study (but with very few subjects) in Hungary in 1930 (42). All the figures are for actual work and do not include allowances for rest pauses. Full details of the working processes are given in the original papers. The tables show that a wide variety of industrial activities demand energy expenditure rates between 2 and 5 Cal/min. These can properly be called light industry and further subdivision or classification is quite impracticable. A few tasks in such industries however occasionally demand harder physical work.

In a study carried out in the Ukraine in 1926-27, Kagan (67) compared the energy expenditure by men assemblin, 0 agricultural machinery, . I) when working entirely by hand and 2) when the machines were put together on a conveyor system. Energy expenditure of the men on hand-assembly varied from 5.2 to 6.4 Cal/min. When the conveyor was introduced, the assembly was broken down into nine separate stages, each carried out by separate operators. Mean energy expenditure rat.es for these men were 1.8, 2.1, 2.6, 3.0, 3.4, 3.4, 3.8, 4.3 and 4.7 Cal/min., respectively. Energy expenditure was much reduced for all operators and the efficiency of as- sem bly greatly increased.

816 R. PASSMORE AND J. V. C. A. DURNIN I/‘olwae 35

TABLE II. ENERGY EXPENDITURE 0~ MEN PERFOR~~~XNO LIGHT ENGINEERING WORK (x2§)

Operation No. of Observ. Energy Cost,

CaT/min.

(a) Operations arbitrarily graded as hea,vy.

Unloading battery boxes from oven Loading chemicals into mixer Machine moulding battery plates Casting lead balls in mould Straightening lead contact bars Rimming battery plates Heavy battery plate casting Machine fitting Lead rolling on roller mill T,oading plates into charging vat Moulding ebonite Light. battery plate casting

4 6.8

2 6 .a

2 5 * I

2 4.8

3 4.6

3 4*4

4 4.2 12 4.2

3 3 * 9 8 3 v9 7 3 l 6 6 3*6

(b) Operations arbitrarily graded as medium.

Tool room workers 4

Turners 4

Joiners 18

Cutting battery plates I4 Plastic moulding 9 Punching battery plates to size 5 Machinists (engineering) 12

Sheet metal worker 8

Joiner trainee 8

Medium assembly work 14 ‘I’ypewriter mechanic trainee 6

(c) Operations arbitrarily gmded as light.

Light machine work (engineering) 8 Fixing ru.bber insulation to battery plates 3 Draughtsmen 5 Drilling (training center) 3 Light assembIy line 3 Inspecting wooden separators 4 Watch and clock repairer trainee 8

2.4 2.2

I.8 1.8 I.8

x.8 x.6

MISCELLANEOUS LABORING ACTMTIES

Load carrying, work with pick, spade and shovel, pushing and pulling of wheelbarrows, are a part of many types of work. For instance many persons engaged in the building industry, in agriculture, in mining, in the iron and steel industry and as postmen, porters and dockers may expend much energy in physical labor of this nature. These relatively simple activities are considered in this section.

There may be much variation in the energy expended during the performance of similar types of work. The method of carrying a load, the size and shape of a shovel, the design of a wheel barrow may all affect the energy required to carry out a specific task.

Load Cm-ying. In 1924 Bedale (7) carried out a classical study on the efficiency of different methods of carrying loads. She herself, aged 29, weight 56 kg., acted as subject and energy expenditure was measured while she walked IQO m., picketl up a load and returned with it at a speed of 4.5 km/hr. The loads were carried in eight different ways. Figure 3 shows t,h .e data for three of these methods. a yoke across the shoulders the energy expenditure was minimal.

October 1955 HUMAN ENERGY EXPENDITURE gr7

TABLE 12. ESERGYEXPENDITTJRE OF WOMEN INMUNITION WORK (60)

Operation

Light turning Turning and finishing Forging Stamping Hoisting shelf with pulley Heavy turning Too1 setting Finishing copper bands Walking and carrying Gauging Cleaning and drying Laboring

No. of Persons

8

4

5

No. of Exper.

37

36 20

12

5 21

25 6

II

I9

4s Wt., kg.

18-33 48-77 19-33 47-65 22-32 S-69

35-44 44-55

54 56 23-44 49-62 21-26 45-59

42-44 55-57

27-44 55-77

18-44 P-55 IS-44 54-66

35-s 44-56

Energy Cost, Cal/min.,

Range and Av.

2.2~4.3(2.5)

1.6-4.6(3.0)

2-9-3*7(3-d $I--3.2(3.2)

(3-3)

2*4-3*7(3*3) 2.0-;.7(3.4)

3*3-3d3.4)

3.2~3*5(3*9) 3.0-4.6(4.0)

+o-O~(4.9)

4.7~eLr(5.1)

TABLE 13. ERERGU F,XPEKDITURE IN LIGHT INDUSTRIAL ACTIVITIES (87)

Occupation

Electrotechnical work Armature winding Radio mechanics

Printing industry Hand compositor Printer Paper Layer Book-binder at the guillotine

Leather trade Shoe repairing Shoe manufacturing

Press goods industry Pressing household utensiIs

Energy Cost, No. of Persons No. of Exper. Cal/min.

2 8 2.2

4 8 2.7

I I 2.2

I I 2.2

I I 2-s

I I 2-3

6 =7 2.7

4 16 3 l o

6 IO 3.8

carried on the hip under the arm, it was maximal. Intermediary values were obtained when the load was carried in trays, in hand bundles, on the head and over the shoulder.

A selection of the data obtained in two other systematic studies is &own in figure 4. Brezina and Kolmer (IS) measured energy expenditure by a young man walking on an outdoor track in the summer in Vienna and carrying loads in a knap- sack, high up on the back and supported by straps. Cathcart, Richardson and Camp- bell (19) investigated two soldiers wearing military equipment, marching on an indoor track in Glasgow. The agreement between the two studies is good and similar results have also been obtained by Atzler and Herbst (5). It will be seen that at slow speeds energy expenditure even with a 43-kg. load is not high, but that when the speed rises over 4 km/hr. energy expenditure increases rapidly. For very heavy loads much more energy may be necessary. Glasow and &Killer (54) found that a man aged 24, weight 72 kg., carrying a heavy sack over his shoulder at speeds from 3. I to 3.5 km/hr. expended 9.4, 11.6 and 16.8 Cal/mm. when the sacks weighed 55, 80 and 1x5 kg., respectively. Dressel, Karrasch and Spitzer (34) found that carrying at 3 km/hr. two concrete blocks, each weighing 25 kg., by means of a yoke with two carrying handles to support the blocks involved about 7.0 Cal/min.

Some values for the effects of different loads when ascending stairs are shown in table 15. The results given by Karrasch are very high, but the step height was more

IL PXSSXIRE AND J. V. G. A. DURNIS VOlU??l e 35

TABLE 14. ENERGY EXPIWDITURE IN LIGHT INDUSTRIAL ACTIVITIES (42)

Activity

Shoemaker, age 27, wt. 45 kg. Fixing soles Filing soles Polishing shoes

Locksmith, age 19, wt. 53 kg. Filing with large file Five other processes

Energy Energy cost, cost,

Csl/min. Activity Cal/min.

Tailor, age 21, wt. 62.5 kg. 2.4, 2.1 Cutting 2.4 2.3 Machine sewing 2.8, 2.9 1.8 Hand sewing x.9

Pressing 3*5 Tailor, age 20, wt. 61.5 kg.

3-3, 3J Cutting 2.7

2.1-2.9 Machine sewing 2.6, 2.7 Hand sewing 2.0

Pressing 4*3

than usual and certainly no orclinarv workman would climb stairs at that speed Gth d such loads.

Working With Pick, Spade and Shovel. Table 16 shows the energy cost of shovelling and hewing. Much theoretical information on the muscular work involved in shovelling and on the energy cost of shovelling various loads t.o several heights has been given in papers by Wenzig (x31) and Kommerell (81). Simonson (123) gives some data for shovelling and other laboring activities in a long paper concerned with the eniciency of industrial work, A summary of similar data is given in the table along with other data for nonspecified shovelling of loads. In general, the usual expenditure involved in using a shovel seems to be about 6 to 7 Cal/min. Some of the data have been slight-Iv rearranged from their original presentation and the authors are asked to accept our apologies.

Pushing Wheelbarrows. Also in table 16 are so.me values for the energy expenditure in pushing loads in a wheelbarrow. Dressel et al. (34) found relatively little difference in using several types of wheelbarrow on a smooth road or on planks. However, the differences would almost certainly be magnified if the surface were very rough. An interesting analysis of some of the muscular factors in barrow work has been published by Crowden (26).

IW-~XL DELIVERY

A postman’s physical work is essentially walking and carrying loads. In towns with many flats there may be much climbing up and down stairs and, in some remote country districts, hill climbing. Crowden (27) has studied the energy expenditure of London postmen both in the laboratory and on their usual rounds which involved much stair climbing. Table 17 gives some of his results. The values for climbing stairs at the men’s own pace include both going up and down but not pauses for the handing in of the mail to the householder. The cost of climbing up and down stairs with the load was found in the four subjects to be almost exactly one and a half times that of walking on the level carrying the same load. It was also stated that the common rate of climbing stairs, up and down, was 80 steps/min., i.e. 40 up and 40 down, and of walking is 90 yd/min.

BUILDING

Much of the work of building and construction involves basic laboring activities already considered. Data for some of the more specialized jobs are arranged in table 18. There are little available data to enable accurate assessment of the energy expenditure of building work. An investigation concerned with finding the usual daiiv ti

October 1955 HUMAN ENERGY ESI’EXDLTU13E S19

FIG. 3. Energy expenditure when carrying loads in various ways. Data horn Bedale (7).

energy expenditure of builders would probably involve more measurements than would be necessary in most other major industries. In addition, building techniques probably differ more than those in any other industry. Mechanical aids and equipment and prefabricated materials are available in very varying quantities. Some of the data come from Italy and the methods of work may be very different in other countries. The reference to bricklaying in the table is for work at ‘normal rates’ in Germany before the war. These are almost certainly higher than apply at the present time in Britain.

MINING AND QUARRYISG

Comprehensive studies of the energy expended by coal miners have been made in England during 1932 ( IOI), in Russia in 1933 (97), in Germany (87) and Italy during World War II (57) and in Scotland in 1952 (49). Table 19 slows the cost of some typical activities. The English, Italian and Scottish results show a remarkable general agreement for the work with pick and shovel, although of course there is con- siderable variation in individual results. The German workers do not give figures for individual activities. They studied 72 miners in 18 different jobs in two coal fields. The gross energy expenditure in calories per minute of pure working time varied from 3.8 to 7.1 with a mean of 4.9 and for total time spent underground the figures varied from 2.4 to 4.6 with a mean of 3.5. The 17 strippers and 2 brushers studied at the coal face in Scotland had a mean energy expenditure of 4.3 Cal/mm. of total time underground. Moss found the corresponding figure in his English survey to be 6.3.

Miners may spend from 30 minutes up to 3 hours every shift walking to and from their work. This often involves travelling over uneven surfaces up and down inclines. In addition, owing to the low ceilings stooping is often necessary. In a laboratory study on 8 miners Moss (101) showed that the average cost of walking was increased by 28 per cent with a half stoop and 65 per cent with a full stoop and as much as 73 per cent when proceeding on all-fours. We ourselves can personally vouch for the fact that the journeys to and from the coal face may be very hard work. Out of 68 measurements of the cost of walking underground in various conditions in Scotland (49), 18 showed an expenditure of over 7 Cal,/min. and of these, 2 were over IO Cal/ min.

The Russian study (97) gives mean figures for hewing, timbering and drilling of 2.9, 4.7 and 3.2 Cal/min., respectively. These values are so far below those obtained in other countries that it is difficult to comment on them. The men appear to have spent IO hours underground each shift and this may be in part: responsible for the low rates of energy expenditure.

Verv few data are available for other forms of mining. In South Africa measure- d

l<. I’,ESMOl<I~ AND J. V. G. A. DUKNIX

Load kg

FIG. 4. Energy expenditure carrying loads at different speeds. Data from Brezina and Holmer (x5) 0 and Cathcart et aC. (19) X.

ments of 8 non-European gold miners ‘lashing in a stope’ have been reported (136).

A large Douglas Bag (1000 1.) was used and expired air was collected over 30 minutes on each subject. Energy expenditure varied from 2.3 to 5.4 Cal/min. (mean 3.3).

There can be no doubt that most miners still, despite the increase of mechanization, carry out hard physical work. Although the basic mining processes involve a high rate of energy expenditure, over-all rates of energy expenditure may be much reduced by rest periods, which may be either voluntary or, more frequently in our experience, caused by the breakdown of essential haulage systems (49). Daily rates of energy expenditure may thus not always be high.

IRON AND STEEL INDUSTRY

Important studies have been made in Sweden (23) and in Germany (87). Table 20 shows the Swedish data. The Douglas bag technique was used. The figures give rates for limited periods of activity only and there is no record of how long such rates were kept up. There is a wide variation in the intensity of the work and some men worked very hard for some periods. This survey was carried out under normal industrial conditions in peace time.

The German survey was much more extensive, but was carried out during the war, when production was not reaching the target required by the war leaders. Many men were working up to 70 hours a week. In addition the work was affected by food shortages and in some cases by air raids. Table 21 gives a small selection of results made from the 12 original tables. The energy expenditure was calculated over the whole of a shift by a combination of time studies and indirect calorimetry. Here it is expressed as a gross over-all rate per minute. Some of these rates are not high. This

Height of Vcr tical Spwcl , Load Energy Cost, Subj. wt., kg. Step, cm. m/min. Carried, kg. Cal/min. R.P. 63 I -5 .2 49.2 s 8.0

2.3 10.4 38 14.2

D.0. 77 T.5.2 8.2 s 990 2.3 IO.7 33 13.2

65 17.2 x7.2 IO 16.2

20 I9=5 40 25.2

60 30.7

Rei.

86 86

Shrwelling S-kg. lfxul clistancc of 1 m., less than I-m. lift, I 2 throwx/min. from ~-2 m. lift, ~2 throws/An.

Shovelling &kg. load distance of 2 111.p

86 less than 1-m. lift---Io throws/tnin 8.5 86 from 1 -2 111. lift, IO throws/min. 10.5

86 Digging trenches, clay soil 8-s

34

34

34

34

34

34

57

49

49

34 86

Activity

Ill., Shovelling g-kg. load distance of 1 0.5-m. lift sand, I 2 throws/min. 0.5-m. lift, gravel, 12 throws/min. I .0-m. lift, sand, I2 throws/:nin. I .O-111. Kit, gravel 91 2 throws/min. t .5-m. lift, sand, ‘co throws/min. r.p-n. lift, p.vcl, 10 throws/n~in.

Shovelling Shovelling Hewing with pick


74 96

594

7.2 6.0

84 6.0 8.0 6.0 6.8

7*0 50

was due in part to large differences be~.wecn the times for work laid down by regula- tions and the times spent in effective tvork . Further the intensity of the work was seldom high, perhaps due to food shortages. The authors also point out that there is a natural subjective tendency to over-estimate the heaviness of the human work in an industry, where loads weighing several tons are moved, although in fact this work is done by machines. Whatever the reasons and despite long hours, the majority of men in the German steel industry during the war were not expending large amounts of energy, There were, however, many jobs involving hard work.

In both surveys there lvere wide variations in energy expenditure. Clearly gen- eralizations in the iron and steel industry are unjustified. There is both a great variety of jobs and a great variety of mechanization in different plants. In both papers details of the processes involved and the degree of mechanization are given. Undoubt- edly some steel workers arc engaged regularly in heavy work, but in most modem plants many are only doing light work.

F’:+rl;a~ ;tncI Gcldrich (42) studied in some detail the cncrgy expenditure of two

822 K. PASSMORE AND J. V. G. A. IiUKNIN I’nlrrnre 35

Tanm I;. I-hERc:Y ExPRxorruaP HY POSTMYS CI.lYBIKC STAIRS AT USUAL PACK (27)

Fnergy Cost, Subj. Age \Vt., kg. Postal Load, kg. Cal/min .

K.W. 56 82 II 9.8 AX. 46 85 16 II.5 A.R. 27 68 16 9.g J.S. 2.5 7’1 16 13.8

‘I’ARLE 1% t<NlW:Y ISXt’EXDITUI(E IS THIS RUILDING INDUSTRY

Ref. 6

55 55 42 42 4= 42 42 42 42 42 42 42 42

Subj. Wt.. kg. Activity

Av. of z

Av. of 2

62

62 62 62 62

65 65 62 65 65

65

hlaking a wall with bricks and mortar at normal rates

Mixing cement Miscellaneous work (carrying tricks, cemrut

or hoIs) Shaping stones with stone-mason’s hammer Preparing wooden straps for plastering Plastering walls Light work in laying stones or bricks IMaking road, preparing ground and laying

blocks of flint .Making road, beating blocks into grouud with

heavy wooden block weighing ao-z8 kg. One man beating alone ‘It0 men beating rlternatcly

Measuring wood Machine sawing Measuring and sawing Joining floor-boards Miscellaneous work chisellillg Sawing softwooa Drillinrr hardwood SaWiDghEUdWGGd

Planing softwood Planing hardwood

4.0 4.i

5.6

3.8

3.1

4-I

3 * 4

4.0

0.7 .j .s I.4 2.4 3.s 4.4 -l.S 5.7 6.3 7.0

-2 9.1

blacksmiths at work at a forge. When using a heavy hammer, the men were expencl- ing between 6.3 and 9.8 Cal/min. They were also employed on many lighter tic- tivities.

Measurements of the energy expenditures of peasants in agricultural tasks have been made systematically in Hungary (43,44), Russia (6S), Italy (16, sS), the Gambia (48) and Nii (112). A selection of the data is set out in tables 22 to 26. The original papers all give full details of working conditions and the type of work done. In the Hungarian survey mid-day temperatures rose up to 35’C. Here time studies were done and an estimation of total daily calorie expenditure made. This was up to 5200

Cal. by some men, who worked very long hours getting in the harvest. &I these studies the men were working with the help of little or no mechanical power. Two recent investigations in Germany (62, 63) compare the work done in hand- and machme- milking and in walking with a horse-drawn plough and sitting on a tractor while ploughing. Table 27 summarizes the data for rates of energy expenditure. Both these

D’tJR J;rjG COATS MINING

823

Type of x0. of Cal./min., ??o. r,l- Cal/min ., Rd. Kork Subj. Mean and Range Ref. ‘rjp of Work Subj. Nean and Range

49 Hewing 18 7.0(,5.0-Io.gj IO1 Timbering 7 7.r(j.6-Io.I) 191 Hewing IO 7.3(6.0- 8.8, J.or Drilling coal 2 7m2(4*9- 9G>

57 Hewing 30 5.7(2.g--IO.,;1 57 Drilling coal 30 5.8(3.8- 8.7) 49 Loading 20 7.1(6.0- Kgj 57 Drilling rock 3s s*3(3*7 -5.7)

IO1 Loading 12 7*7(6*3- 9.4) 57 Pushing tubs I 2 8.o(s.g-10.2)

37 Loading 30 6.6(5.0- 8.8) 40 Packing 3 6.8 49 Timbering 18 5=7(4J- 9.0)

Energy Cost, Cal/min. Mean and

Type of Work Range

O~pen hartlt Slag removal 11.fi(10.6--12.6)

Dolomite shovelling IO.<)( 9.p12.9)

Tipping the moulds 6.0 Heavy mill Tending the heating furnaces IO. 2 ( 6.7-16.2)

Hand rolling 8*9( u- 9-3) Tending the sawpits 6d .5*7- 7.2)

Type of Work

Wiue rod mill Roughing Wire bundling

Energy Cost, (:1al /min. Mean anrl

Range

8.2(7.0-10.4) L0.2(Q.3-12.2)

14-inch merchant mz’ll Merchant nlill rolling Forging Fettling

9.4(7.0-11.0) 6.5(6.4- 6.7)

4-9(4*8- 4-9)

papers give a detailed analysis of the changes in the work requi.red of the human operator consequent upon the introduction of mechanization.

Some data (I x7) for grooming and the care of horses by soldiers ~-e summarized in table p.

Tables 22 to 27 provide a quantitative demonstration of the fact that farming demands hard work. Time studies in several seasons of the year are necessary if com- pari.sons are to be made with urban industrial workers.

We know of no studv of the energy expenditure rates of agriculture in Asia. d

Kscellent physiological studies have been made in lumber camps in Sweden (g2), in Finland (73) and Germany (68a). Table 28 shows some of the Swedish results. There is no doubt that heavy expenditures of energy are involved. This is confirmed by dietary studies and many men in both surveys have been recorded as consuming over 5000 Cal/day and some over 6000. Lumbering is pcrl~tl~s the hardest physical work undertaken.

Kaminsky (68a) has measured the work done transporting wood by sleigh over the snow during the German winter. Pulling the sleigh uphill into the forest cost 10.5 Cal/mm. and loading the wood off and on the sleigh between 6 and 7 Cal/min. Long hours were worked and estimates of both energy expenditure and food intake i were over 6ooo Cal/day.

Gl&er (52) has devised an ingenious technique for measuring in the laboratory the efficiency of work with an axe. Table 2g shows the very high rates of energy expenditure that may be involved.

FISHING INDUSTRY

One study as yet incomplete (14) has been made on a trawler in the Netherlands fishing fleet. This showed that. \vhen bringin, q in the trawl, 11x men do hard physical

824 I<. I’ASShIOKI< ANL, J. V. G. A. DUKNIN Ibhme 35

TABLE 21. OVER-ALL RATES OF ENEIXY EXI~ENI)ITURE IN A W?LK’I‘IME STEEL INUUSTRY (Germany, 87~

Type of Work Rolling Work Bar cleaner

Furnace man Furnace man

rvagon Tvorhsllop

Smith

Striker

Wire-clralver

\Qre-wnsher Forge (mcchaniec~l)

Smith Smith’s mate

Moaldi~zg Moulcler

Sloulder Core layrr

\Veeks Working Time, hr.

72.5 70

i”

67.5

67.5

55.5 is.;

io

70

68 .j

52 52

Over-all Energy I:xpend. Rates,

Cal/mill,

3 8

.i . 2

4 . 3

3.6 4.0 A.6

j.1

2.4 2 .o

3.7 .I I

.i . 0

TABLE 22. ENIW:Y JSIPENUIUJ~~ I’: IN ACI~KU~~CUWE, IIu~~g:try, rt),;~ (+,;, .gd?

So. of Subj. No. of Exper. .r\ctivity Cal/roiu.

6 29 Mowing wheat ;.7(6,2-10.1)

2 0 Mowing barley ;.0(5.6- 8.T\

4 12 Setting up stooks 6.6(S.1- 8..+1

3 12 Ilirl<lin,rr wheat 7.:;(6.2- 8.6)

work. Manq’ measuretwxts of cncr,qy ~spcnditure up to IO Cal/nliu. \v2rc ILUC.!C,

Work at this rate was carried out for many hours on end ant1 ;t daily energy eq>cntIi-

ture of over jOO0 Cal. was rrmirltainetl for 2 or more days.

Donald and Davidson (31) have measured the oxygen consumptio~~ OF underwater divers and frogmen and table 3~ gives a summary of their results. The figures have not been converted into Calories per minute since the oxygen requirement itself is of much more practical importance. The levels of oxygen uptake CL t rest wdcr

water are remarkably low and sometimes but little above basal levels. Even when doing apparently very heavy work under water, the booted diver does not expend energy at high rates. This is presumably clue to the very great restrictions on leg movements. Finned underwater swimmers, able to move their limbs freely, have lnuch larger oxygen upt:tkrs.

Tables 31 to 34 give cln~a obtained for British soldiers at home (I ;> IS, 39, 741 and in the tropics (117)~ for Jugoslav soldiers (116) and for the TJnited States Army. (IIS). The Jugoslav paper (r16) has references to reports giving data obtained in the Russian Army, but we have not been able to see these. The military studies have been carried out with met iculorls c:are, and accurate values are available for :na.ny

standard military tasks.

825

‘FABLE 23. &ERGY EXPENDITU’RE IN AGRIC!ULT?JR.fi;, kSSia, 1933 (68)

Subj.

P s P w 4

;a1 A Sar Sar

Sex

M M M M F F F F F

Age wt., kg. 24 65 2r 67

24 65

32 76

I9 fig

I9 52

19 63

19 52

19 5 2

Activity Roughing Ploughing Thrashing rye Thrashing rye Binding oats Binding oats Binding rye Biding rq-c Weeding m.pc,

Cal/min.

6.9(6.3-7.8)

5*4(5*2--5.6) 5.0(4.8--5.2)

4*5(4*2-4.9)

.3*3(3*0-3*8)

4*1(3*6-4.7)

4*2(3-s--4.9)

4J(4-I-SJ)

3*3(3*0-3.5)

The oxygen consumption of airplane pilots has been determined under artificial conditions in a dummy cockpit by Karpovich and Ronkin (71). The mean energy expenditure for 27 pilots, average weight 73 kg., when sitting in a cockpit and manip- ulating controls, was 1.7 Cal/min., a rate similar to most sedentary occupations. This paper gives references to other American work published in service memoranda with restricted circulation.

Corey (29, in a short report, showed that the metabolism while piloting an air- craft varied from IO to about 60 per cent above the normal sitting energy rate; a range of values of from 1.5 to 2 Cal/min. probably covers the majority of activities during piloting.

APPLICATION OF ARTIFICIAL RESPIRATION

The results of one study (69) are recorded in table 35. The figures are averages for IO men and IO women operating respectively on 4 male victims (weights 48-82 kg.) and on 4 female victims (weights 41-75 kg.) at 12 respirations/min. and using five different methods.

EFFECTS OP AGE, SEX, BODY SIZE, KAC,E AND CLIMATE

The effects of these factors on basal metabolism have been extensively, perhaps exhaustively, studied (36,45, 77, II~). As already pointed out, man is only metabolizing at approximately basal rates when asleep or lying down and this contributes but a small proportion of the daily energy expenditure of active persons.

There is little evidence that the mechanical efficiency with which a standardized muscular movement is made is subject to important individual variation. The obvious differences between the energy expended by old and young and by the inhabitants of the tropics and of temperate zones are brought about mainly by variations in the economy of muscular movement and in the amount of surplus activity, The young are spendthrift of movement, whereas with increasing years unnecessary physical activity is curtailed. Consequently to compare the rates of energy expenditure by juvenile, adult and elderly persons employed at the same type of industrial work, accurate timing of their various activities would be necessary. The young will always find time for secondary energy-consuming activities, surplus to the main task.

The evidence that there are no significant metabolic differences in the performance of standardized muscular work is, however, not great. Mahadeva, Passmore and Woolf (96) investigated in 50 subjects the relationship between energy expenditure, during standardized walking and stepping, and weight, height, age, race and sex. Energy espenditurc was closely correlated with body weight, but not significantly

826 R. PASSMORE ,4ND J. V. G. A. DURNIN

TABLE 24. ENERGY ~~PEND~~RE IN AGRICULTURE, Italy, 1945

Ref. Subj. Activity

16 I 5 men, aged I 5-55 Mowing with a scythe 16 15 men, aged 15-25 Mowing with a horse-drawn reaper 16 8 WOmen,aged IS-29 Preparing bundles of cut corn T6 I I men, aged 15-g Binding bundles of corn I6 8 men, aged 19-41 Preparation of stooks 16 4 women, aged 14-2~) Preparation of stooks 16 3 - men, aged 16-41 Loading stooks onto carts 58 7 men, aged 15-41 Threshing, throwing sheaves from pile to

ground 58 7 men, aged 15-41 Threshing, throwing sheaves towards thresh-

ing machine 58 7 men, aged 15-41 Threshing, thro\ving sheaves up to threshing

machine 58 -5 women, aged 13-25 Threshing, binding sheaves 58 j women, aged 13-25 Threshing, throwing sheaves into machine

Cal/mm. (Mean)

6.8

4.3 5.0 6.8

5*5 4.8

5.6 6.0

with height, age, race or sex. The series was small, but sufficient to indicate that these other factors have no large effect on muscular efficiency.

Astrand (3) has measured the energy expenditure of children and adolescents when running on a treadmill and working on a bicycle at submaximal rates. The experiments on the bicycle ergometer showed no differences between the two sexes. On the treadmill at any given speed, the net oxygen uptake per kilogram of bodv weight fell progressively as age advanced from 5 to 15 years. The younger children were at a mechanical disadvantage owing to their shorter legs and this is suggested as a possible reason for the increased oxygen consumption.

Seltzer (122) has measured the oxygen uptake of 34 males aged 20 to 24 during moderate exercise-walking on a treadmill up a grade of 8.6 per cent at 5.6 km/hr. for 15 minutes, He also made a large number of anthropometric measurements and has attempted to correlate these with rates of energy expenditure. In moderate exercise oxygen consumption correlated best with chest circumference (o&7), then with weight (0.771) and surface area (0.724) and only very roughly with other physical measurements, height (0~363) and leg length (0.275). Seltzer calculated the mechanical efficiency of 44 different anthropometric groups within the whole sample. The lowest figure for the efficiency of any group was 15.0 per cent and the highest 16.1 per cent. He makes a case that in moderate exercise, those whose body build is ‘lateral’ rather than ‘linear’ have the greater mechanical efficiency. His argument is, however, largely a discussion of the functional significance of differences, which his previous analyses had shown to have no statistical significance. On any reckoning these differences are small and weight is the most important factor in determining individual energy expenditure.

The effect of temperature on the metabolic cost of work is also probably Vera small. Nelson et (II. (105) studied by partitional calorimetry the heat exchanges of three acclimatized men while standing still and walking in a series of seven hot environments (32c)--490C.). Metabolic heat production for a given amount r)f work remained unchanged irrespective of changes in environmental conditions. Gray, Consolazio and Kark (59) found that for men working at a Axed rate on a bicycle ergometer in standard 0utfit.s of clothes the metabolism only varied by up to 4 per cent over the temperature range -q” to +32OC. IIorvath and Golden (61) founct

x0. of Subj. Sex

4 M

5 M

4 M ‘, M

r3 F 4 F

ENERGY EXPESDITURE IN AGRKXJLTURE, The Gambia West Africa, 1953 (48)

EfffXtiW2 ‘ICT I 0. 0 f

&F Wt., kg. Temp., “F Observ. Activity Cal/min.

25-38 63(56-68) 63-70 11 Clearing shrub and 7. I (5.8-8.4)

dry grass 24-36 57 (49-W 69-76 13 Ridging (deep dig- g .s (5. s-15.2)

ging) 21-28 67(64-70) 74-80 x2 Planting groundnuts 3.7 (3. 1-4.~)

X9-33 63(61-w 63-71 9 Weeding .53(3.8-7J3) 18-30 54 (48-58) 73-81 II Hoeing 5.8(4.8-6.8) I&-28 57 (43-65) 75-84 IS Pounding rice 5*0(3*9--6.4)

the metabolic rate of five men increased by about 7 per cent w-hen performing standard work at temperatures of - 16’ to -47OC. Very cold temperatures may thus increase the energy cost of work, but, except possibly under arctic conditions, the eflect will be negligible.

At high temperatures (32OC., relative humidity 70%) Robinson (I 19) corn- pared a large man and a small man working on a treadmill at over 12 Cal/mm. The efficiency of the 2 men in performing the work was the same, but the large man had more difsculty in dissipating metabolic heat and his rectal temperature rose much more than that of the small man. This was presumably because the small man had a larger surface area relative to the metabolizing mass. This experimental observation is consistent with the view that small men might be at an advantage over large men in performing hard physical work in the tropics.

The most important observations on the effects of temperature on energy expenditure under field conditions are those of Richardson and Campbell (I I 7). They found no significant differences between the energy expended by British soldiers in India, when marching at about 3.4 mph in drill order (load about x3 kg.) during the hot weather (temperature 27OC., relative humidity 92 %) and during the cold weather (temperature IoOC., relative humidity 67 %). In fact, energy expenditure was always higher by up to IO per cent in the cold weather. This difference was attributed entirely to difficulties in tirne keeping. On the cold invigorating winter mornings, the men stepped out briskly and were always a little ahead of schedule. In the dull hot humid atmosphere during the m.onsoon, there was a constant tendency to slacken pace. These slight differences in pace, in the authors’ opinion, were alone responsible for the differences in energy expenditure. This work was carried out with meticulous care on six young soldiers.

DArLgl ENERGY EXPENDITURE RATES

The data set out in the tables presented have given rates of energy expenditure calculated per minute. For assessing energy expenditure over periods longer than xo to 15 minutes, metabolic measurements must be supplemented by time studies and accurate recording of activities. With the help of these it may be possible to build up an estimate of calorie expenditure over a longer period. Most textbooks of physiology and nutrition contain tables giving estimates of daily energy expenditure for various occupations drawn up in this way. This summation method of estimating calorie expenditure (and thus requirement) was criticized by Keys (75) in 1949, who pointed out that the assessments had usually been based on inadequate lo,rrir-al data and insuficient knowledge of the actual lvork processes. This is

physio- true of

828 R, PASSMORE AND J. V. G. A. DURNIN Volume 35

TABLE 26. ENERGY EXPENDITURE IN AGRICULTURE, Nigeria, West Africa, 1954 (x12)

Six wbjeds mean weight 55 kg. Mean Energy XIean Energy

No. of cost, A 0. 0 v f cost,

Observ. Activity Cal/min. Osberv. Activity Cal/mm.

12 Grass cutting 4 ’ 3 I2 Head planning, load 3*5 wt., 20 kg.

I2 Bush clearing 6.1 12 Log carrying 3 04 12 Hoeing 4.4 l-o Tree felling s.2

TABLE 27. ENERGY EXPENDITURE m AGRICULTURE, Germany, 1953 (62, 65)

Subj. Activity Cal/min. 7 Subj. Activity

Ages IS-39, wt.

57-86 kg. Age 28,

kg. wt. 64

Milking: by hand Machine milking I Jx2if

Machine milking z pails 3*9(3*1-4-a Cleaning milk pails 4*4(4*3-4*5)

4.7(3.5--6.3)

3 .4 (3 . 2---3 .7 )

16 observ. 6 observ.

8 observ. I 4 observ.

Horseploughing Horseploughing (an -

other type of plougll) Tractor ploughing Tractor ploughing (an-

other type of tractor)

‘,c ;.:

4.2

462

much past work, but recently in Great .Britain there have been several atten~pts to measure energy expenditure over long periods by improved summation methods (39,49, III, 132). Tables 36 and 37 are illustrative and give data which we (49) have obtained for two individuals, one a clerk with a sedentary occupation, the other a coal face miner. For each, the necessary information was collected over a whole week: a week is a minimum period. since any daily average figure which did not include data obtained over the week-end period would be misleading. These tables also give the daily average calorie intake over the same period obtained by a simultaneous diet survey. Table 38 is a summary of these surveys in Great Britain in which simultaneous assessments of energy intake and energy expenditure have been made. They were carried out by teams of experienced dietitians and of physiologists. The figures show that such teams can arrive independently at results which agree within TO per cent.

The estimation by diet-ary survey of the calorie intake of even a rekttively homo- geneous group of persons is subject to wide error, to which the use of tables of food analyses contribute. Woolf (135) has discussed the accuracy of dietary surveys and concludes that even with good technique the coefficient of variation in estimating calorie intake is at least ro per cen.t. In most circumstances, we think that estimations of energy expenditure rates can be at least as accurate. These may thus provide a~,n alternative method for indicating the calorie needs of population groups. 111 some circumstances, perhaps in industrial. communities, surveys of energy expenditure may prove simpler, less expensive and more informative than large scale dietary surveys.

In this field. of research, if experiments are designed to obtain data with a high degree of accuracy for each individual subject, inevitably onlv a limited number of persons can be studied. Carefully carried out field experiments,% which the accuracv compared favorably with that of many controlled laboratory investigations, require large numbers of experienced staff and assistants. Even then observations CM. only be made on small numbers of subjects. There is a large variation in energy expend.iture by individuals leading the same type of life. The energv expenditure of the same individual varies from day to day and from week to week f and persons in exactly similar


TABLE 28. ENERGY EXPENDITURE DURING LUMBER WORK (92)

Type of Work

Timber cutting irt the winter Tree-felling with felling saw Trimming of felled trees Barking Cross-cutting with bucksaw Fire-wood cutting in the summer Tree-felling with bucksaw Trimming of felled trees Dragging of firewood Cross-cutting in a sawhorse Barking in strips Cleaving of softwood Cleaving of birch billets Stacking of firewood

No. of Subj.

II

II

II II

Cal/min., Mean and Range

[email protected])

10.2(8.7-1x.6)

10.1(8,;-12.0)

9*0(7+-~0*5)

g.6(8.2-1x.0) 8.4(8.1- 8.6)

g.8(8.7-x0.9) 7.8(6.9- 8.7)

5*9(5=2- 6.5) 9.7(9.2-10.1)

8.g(8.6- 9.1)

6*3(57- 6891

TABLE ~~.ENERGY EXPENDITURE WORKING WITH AN AXE (52)

Subj., age 23, wt. 82 kg.

Wt. of Axe, Speed, Energy Cost, Wt. of Axe, Speed, Energy Cost, kg. Blows/min. Cal/min. Qc* Blows/min. Cal/min.

Perpendicular blows Horizontal blows 0.6; 36 11.4 0.65 34 12.0

I.25 34 11.9 I.25 34 13.2

2.00 33 13.0 2.00 33 12.3

I.25 19 6.9 I.25 35 11.0

1 l 25 51 24.1

occupations, because of differences in body weight and in activities outside waking hours, may have markedly differing values for their energy output per day. Although it may appear undesirable to advocate the use of methods which do not reduce the errors of individual observations to a minimum, nevertheless we feel it will be more profitable in the future to accumulate information over a much wider field, even at the expense of some inaccuracies in individual results, rather than to persevere with the laborious techniques which have hitherto been used.

In planning fresh surveys it is essential to consider how many measurements by indirect calorimetry on each subject are desirable and how much data from tables of energy expenditure can be utilized. Such decisions will be determined to a large extent by the length of time which each subject spends on any activity and by the experience of the observer. Many activities during work, and many recreational activities, last for only a few hours in the week. Little error is introduced by using tables to assess the energy cost of such activities. For example, if a man plays one game of football in a week, lasting go minutes, and an average value taken from tables of 6 Cal/min. is used, this gives a total expenditure of 540 Cal. If, in fact, the man were very energetic throughout the whole game and had an average energy expenditure of 8 Cal/min., or if he were in a wing position and had relatively little of the play so that his over-all metabolism was only 4 Cal/min., the deviation from the assessed total would be only =t 180 Cal. Thus in one week the use of a table to assess a single outburst of activity such as a game of football will introduce into the daily average an error no more than =tq Cal/day, a negligible amount. If it is possible to observe

830 R. Z’ASSMOICE AND J. V. G. A. DURNIN ?ToltLme 35

'hi.)'. 30. o2 UPTAKE OF DIVERS (l/min. N.T.P.), SUMMARY OF RESULTS (31)

No. of No. of state Exper. Mean Min. Max. State Exper. Mean Min. Max.

Booted Divers Finned Underwater .!fhimmers Tank SxGmming baths Sitting I3 0.25 0.20 0.32 Suit and fins Standing I3 0.27 0.22 0.30 I .3-I. 7 ft/sec. 9 2.32 1.60 2.68

Min. movement 13 047 0.40 0.73 I. 7-2.3 ft/sec. 4 3.09 2.65 3.60 Max. movement 13 I*53 1.24. I.96 No suit and fins Open water I .3-I. 7 ft/sec. 4 2.02 I.90 2.33

I ft. Mud x .7-2.3 ft/sec. 4 3.16 2.63 4.15 Min. movement 9 1.08 O-73 1.61

Max. movement 9 1.71 1.20 2.45

2 ft. Mud Min. movement g 0.98 0.61 I.65

Max. movement g I.96 1.41 2.35

TABLE 31. ENERGY EXPENDITURE OF BRK~ISH SOLDIERS

Ref. Xo. of Subj. Wt., kg.

I8

39 18

IS

18

39 39 39 I8 IS 18

I8

39 74

17 18

IS

I&

39 39 74 IS

I8

39 IS

I7 74 18

Av. of 2

Av. of 12

Av.bf 5 Av. of 6 Av. of 7 Av. of 6 Av. of 6 Av. of 5

Av.‘of 3

Av. of 8 Av. of 6

I

Av.Iof 6 Av. of 7

I

Av. of 5 Av. of 12

I

I

Av.‘of 3

Av. of 6 Av. of 2

I

I

51 70 74 68

64 71 73 66

71 79 58 69 67 68 68

71 68

73 67 70 68 68

79 78 7,3 80

68 68

Activity

i1n ti-gas drill Weapon training Kit inspection -\rms drill 3Iusketry Polishing equipment IMixed sports in gymnasium* Cleaning kit and rifle Throwing hand grenade Guarcl and sentry drill Company drill Squad and platoon drill Mixed sports outdoors* Slow march Marching (2 mph) with 27-kg. load I3 ayone t exercise Physical exercises Doing fatigues Ironing equipment Drill LMarching (3 mph) with z7-kg. load Quick marching Field operation Digging trenches Obstacle course Assault course %Iarching (4 mph) with 27-kg. load Rapid marching

* Over-all figure including rest pauses.

Cal/min.

2.0

2.2

2.3

2.4 2.7

2.7

2.7 2.7 2.9 3.2 3*4 3.7 3.8

3.8 3*9 3.9

the game, the error should be even less than this. On the other hand, it is most important to try to obtain reliable figures for the duration of each activity throughout the 24 hours. As far as possible such information should be obtained by independent observers, although inevitably for some parts of the day the subject must be responsible for recording the times spent on his activities.

In every survey it is essential that there must be facilities for making measure-


TABLE 32. ENERGY EXPENDITURE OF BRITISH SOLDIERS IN INDIA (117)

Activity Cal/min. Activity Cal/tin. Infantry, av. figures for IO men aged 24, wt. 61 kg. Horse artillery, av. figures for 8 men aged 23, wt.

Standing at ease Standing at attention Cleaning equipment Signalling with morse, semaphore and

lamp Musketry-training

-firing on range Sentry duty Squad drill-without arms

-with arms Throwing grenades Marching in drill order (load 13 kg.,

speed 3.4 mph) Bayonet exercises Field exercises in extended order Digging trenches

65 kg* I.3 Horse clipping 4.2

I*4 Cleaning harness 4.8

2.9 Cleaning guns 51 3** Trotting on horseback S-6

Cantering on horseback 6.5 3*2 Jumping on horseback 7*6

3.8 Harnessing and unharnessing 6.9 3-5 Grooming horses 8.3

4.7 4.8

4*7

6.3

6.7

7.8 8.8

TABLE 33. ENERGY EXPENDITURE OF U. S. SOLDIERS (x15)*

Activity Cal/min.

Inspection 2.4 Fatigue duties 2.4 Drill 3*s Digging foxholes (mixed with march- 4.6

ing and short rest periods) Mass games 5.2 Field march 54

Activity Cal/mine

Field march with rifle 6.5 Obstacle course with pack and rifle 6.6

Creeping and crawling with full equip- 7.9

ment Field march with rifle and 27-lb. pack

at 3 mph S . o

Field march with heavy pack 3.9

* Values applied to standard rso-lb. man.

ments by indirect calorimetry. No assessments should depend solely on the use of tables. Nevertheless tables, combined with an accurate time study, can reduce the necessity for large numbers of measurements on each subject.

In addition to the use of tables, another way of simplifying surveys of energy expenditure may be to reduce the number of gas analyses and rely in part on determinations of pulmonary ventilation. Durnin and Edwards (38a) have shown in field studies that, if a small number of measurements of energy expenditure are made on any one individual, it is then possible to use the pulmonary ventilation alone as an index of the energy cost of activities; the increase in experimental error is less than 5 per cent. Such a technique, together with a knowledgable use of the tables in this review, should make it practicable to carry out field surveys of energy expenditure on a much more extensive scale than has been possible up to the present.

Under controlled conditions with the subjects living in the laboratory or in hospital for periods as long as 2 to 3 weeks, measurements of total daily energy expenditure can be very accurate. In one study (110) in a metabolic ward of a hospital, the error appeared to be less than 5 per cent. The technique may thus be a useful tool in investigatin, 0 obesity and other metabolic disorders, in which the energy balance may be upset.

83” R. PASSMORE AND Je V. CT. A. DURNIN Volume 35

TABLE 34. ENERGY EXPENDITURE OF YUGOSLAV SOLDIERS (1x6)*

Activity

Dressing and undressing Driving a tank Adjusting caterpillar tracks CIeaning a tank Rifle exercises, lying down Rifle exercises, kneeling Taking off and putting on car tires Cleaning equipment Cleaning gun

Cal/min.

24 24 2.4 2.8

2.8

3.2 3.3 3.6 367

Activity CalJmin.

Rifle exercises, standing 3-g Horse riding, slow 4-3 Cleaning horse 4.5 Lifting car by jack 4-S Carrying boxes of ammunition 6.3 Horse riding, trotting 6.5 Digging a trench 8.0

Horse riding, galloping 8.1

* Mean age of subjects, 22 yr., mean wt., 67 kg.

TABLETS. ENERGYEXPENDITUREDURINGARTIFICIALRESPIRATION (Cal/min.) (69)

Method of Art. Resp.

Men operating on men tvomen operating on women

Holger Hip Roll Prone Schafer Silvester Nielson Pressure Hip Lift

2.7 3-s 4-6 s-1 s** 2.2 2.4 3.2 3-s 3-7

GRADING OF INDUSTRIAL WORK

A convenient grading of the physical effort required for different types of industrial work has long been needed. Industrialists use a variety of arbitrary gradings, which for the most part have little physiological support. Christensen (23) in dis- cussing the results of his measurements of energy expenditure in the Swedish steel industry, suggests the following definitions of different grades of work:

Unduly heavy, energy expenditure over 12.5 Cal/min. Very heavy, energy expenditure over 10.0 Cal/min. Heavy, energy expenditure over 7.5 Cal/min. Moderate, energy expenditure over 5 .o Cal/mm Light, energy expenditure over 2.5 Cal/min.

These figures correspond approximately to rates of oxygen consumption of 2.5, 2.0,

1.5, 1.0 and 0.5 l/min., respectively. The tables in this review indicate that these definitions correspond with common conceptions of what is and is not heavy work. In our opinion Christensen’s definitions are sensible and their introduction into general use would be helpful to both industrialists and physiologists.

The definitions, of course, only apply to rates of work which are carried on continuously for periods of a few minutes. Periods of heavy work must be punctuated by rest pauses. These will naturally reduce the over-all rates of work for a whole working shift and the definitions do not apply to average daily rates of work. How hard a man is capable of working for long periods of time, months, years or even a lifetime is another problem.

HUMAN WORKING CAPACITY

Those of us who lead for the most part sedentary lives know that on occasions we can carry out physical work for short periods at rates very much faster than the usual rates of those regularly employed as manual laborers. At a week end we can work in the garden at a rate which could not be kept up day after day and week after week. Nearly a hundred years ago Playfair (II~), Professor of Chemistry in Edin- burgh, after a study of the behavior of rural postmen and of infantrymen, suggested


TABLE 36. EKIZRGY OUTPUT AND INTAKE OF A CLERX OVER I WEEK

Ian C., Age 29, Ht., 66 in., Wt., 66 kg., Occupation, CZerk

Activity

In bed Daytime dozing

Total Time Spent hr. min.

54 4 I 43

Cal/min. Total Cal.

1.13 3,670 1937 140

Recreational aftd off work: Light sedentary activities Washing, shaving, dressing Playing with child Light domestic work Walking Gardening Standing activities Watching football

Total recreational and off work 62 32

31 14 1.48 2,810 3 18 3*0 590

30 3.2 100

7 14 3.0 1,300 8 35 6.6 3,400 d 48 4.8 810

45 1.56 630 2 IO 2.0 260

9,800

Working: Sitting activities Standing activities Walking

22 22 1.65 2,210

25 57 I.90 2,960 I 22 6.6 540

Total working 49 41 5,710

Grand total 168 19,320 Daily average 24 2,760 Food intake (daily av. determined by diet survey) 2,620

that the upper limit of useful physical work that a man can perform on 6 days of the week throughout the year was the equiva>lent of a 2o-mile walk a day or a I4-mile march with a 6o-lb. pack. Higher rates of work were likely to be associated with physical breakdowns due to cumulative fatigue.

Lehmann (86) and Miiller (102) have recently been investigating this problem again. They suggest that in order to prevent evidence of fatigue the intensity of the working rate and the length of the compensating rest pauses must be so adjusted as to give gross over-all rates of energy expenditure of not more than 5 Cal/min, This they call an ‘endurance limit.’ It represents approximately the upper limit of work that can be performed without an increasing accumulation of lactic acid and without a rise in body temperature. It corresponds approximately to walking on the level at about 3.8 mph. A man, so the German workers say, should be able to maintain an over-all working rate of this order for 6 days a week, week after week, and year after year. It is equivalent to a daily walk of about 30 miles. Playfair’s postmen in rural Scotland would have several steep hills to climb in their 20 miles and the two standards probably do not differ greatly.

Work at 5 Cal./min. for 8 hours corresponds to 2400 Cal. expended at work. If we allow 500 Cal. for 8 hours in bed and. about 1400 Cal. for the 8 hours spent off work (49, see also tables 36 and 37), the total energy expenditure for the 24 hours is 4300 Cal. This probably represents the upper rates of daily energy expenditure that can be maintained regularly in heavy industry. It is slightly higher than rates recorded in British (49) and German (87) coal miners. Food intakes corresponding to very much higher rates have on occasions been recorded. This is notably so in the

834 R. PASSMORE AND J. V. G. A. DURNIN Volume 35

TABLE 37. ENERGY OUTPUT AND INTAKE OF A COAL MINER OVER I WEEK (49)

John E., Age 32, Ht., 6g i~., Wt., 67 kg., Occupation, Stripper

Activity

In bed

Total Time Spent hr. V&Z.

58 30

CaI/min e

0.94

Total Cd.

3,690

Recreational and off work: Light sedentary activities Washing, shaving, dressing

Walking Standing Cycling Gardening

38 37 I-59 3,68o 5 3 3.3 1,000

1s 4-9 4,410 2 16 1.8 250 2 25 6.6 960 2 5-O 600

Total recreational and off work 65 21 10,900

;Vorking: Loading Hewing Timbering Walking Standing Sitting

12 6 6.3 4,570

t 14 6.7 500 51 57 2,340

6 43 6.7 2,700 2 6 I*3 230

I5 9 1.63 1,530

Total. working 44 9 11,870

Grand total 168 26,460 Daily average 24 3,780 Food intake (daily av. determined by diet survey) 3,990

TABLE 38. SIMULTANEOUS MEASUREMENTS OF DAILY EXERGY EXPENDITURE Am INTAKE

Daily Daily (Expend./ No. of Days Cal. Cal. Intake)

Ref. Subj. Obs. Nature of Activities Expend. Intake x I.00

III 5 13 Male students, 5 days hard work and 8 3, po 3,610 97 days sedentary

132 77 7 Military cadets, normal training 3,420 3,710 92 39 12 7 Military cadets, normal training 3,430 3,350 102

39 12 7 Military cadets, normal training 3,450 3,410 101

49 10 7 Male clerks in colliery office 2,800 3,040 92 49 19 7 Coal face 3,660 4,030 91

Iumber camps (68a, 73, 92). Lumbermen are, however, a carefully self-selected group with physiqaes far above the average. The figure of 5 Cal./min. given by Lehmann and Miiller is intended to apply to an average cross-section of an industrial com- munity. Lumbermen do undoubtedly work for long periods at high rates, but the accumulation of several weeks with good wages or the curtailment of opportunity because of the long hours of winter darkness in the northern forests usually result in long periods of absence from work. The lumberman does not carry on with his work regularly year-in and year-out like the coal miner.

Mtiller emphasizes that this endurance limit gives only a rough idea of what mav be expected of men in heavy industry. In light industry many oth.er factors, such as the necessity to maintain awkward postures or the excessive use of one set of muscles may limit capacity for work at much lower rates of energy expenditure.

Ociobeu rg;s’ HUMAN ENERGY EXPENDITURE 835

ENERGY EXPENDITURE AKD CALORIE REQUIREIUENTS

In this review we have attempted to collect together some of the knowledge that is available concerning the rates of energy expenditure in various human activities as determined by physiological methods. Much more information is available from dietary studies of the energy intake of different population groups, and dietary studies provide indirect information on over-all rates of energy expenditure. Both sources of information are necessary in drawing up physiological scales of calorie needs. Such scales are of great importance since they must be the basis of any form of food rationing in times when food is scarce. Probably the best modern statement of calorie needs is that published by the Food and Agricultural Organization of the United Nations (46). This report was first issued in 1950, and is undergoing revision at the moment (47).

Nutrition and industrial health are still both young sciences. In this review we have tried to gather some of the data in one branch of physiology common to these two sciences. Knowledge of the energy expenditure of an individual will usually indicate the food needs. But the energy needs can also be indicated from the dietary intake, and we feel that a comprehensive and critical review of the literature on dietary intakes would also be most useful at the present time. The study of energy expenditure and of food intake is complementary, and much information is already available. A more precise understanding of this data will increase our practical knowledge of man’s food requirements and capacity for physical work.

the We wish to

manuscrip t. thank Dr. K. Mahadeva for much help in the early stages of the preparation of

REFERENCES

1. ABBOTT, B. C., B. I~PGLA~D MD J, M. RITCHIE. Physiological cost of negative work. J. I%ysiol 117: 380-390, 1952.

2. &MUSSES, E. Experiments on positive and negative work. Ergono~~ics Society Sy?~@oshn on @f@zce (edited by W. F. Floyd and A. T. Welford). London: Lewis, 1953, pp. 77-83.

3. ASTRAND, P. 0. Experimentczl Shdies of Physica. Working Cujwcity in Relation to Sex and Age. Copenhagen: Munksgaard, 1952,

4. ATZLER, E. AND R. HERBST. Arbeitsphysiologie Studien. PJEiigev’s -4rcJz. ges. Plsysiol. 215 : 290-328, 1927.

5. ATZLER, E. AXD R. HERBST. Die (Ikonomie des Lasttragens iiber eine ebene Strecke. Arbeits- physiologic I: 54-74, 1929.

6. BAADER, E. AXD G. LEHXASX Vber die okonomie der Maurerarbeit. Arbeitsplzysiologie I:

40-53, =929* 7. BEDALE, E. M. Comparison of the energy expenditure of a woman carrying loads in eight

different positions. 111. ResearcJl cow& Indmtrial htigzce Research Board no. 29, 1924. S. BENEDICT, F. G. A study of prolonged fasting. Carnegie Inst. Wash. Pfcb. no. 203: 343-351,

1915 9. BEKEDICT, F. G. AND C. G. RENEDICT. Mental effort in relation to gaseous exchange, heart

rate and mechanics of respiration. Carnegie ht. Wash. Pzdb. no. 446, x933. IO. BEXEDICT, F. G. AKD T. M. CARPESTER. Influence of muscular and mental work on metabolism

and efficiency of the human body as a machine. U.S. Dept. Agric., O$. EX/WP. Sta. Bill. 208,

19099 I I. BEKEDICT, F. G. AND T. &I. CARPESTER. Metabolism and energy transformations of healthy

man during rest. Cumegie Inst. Wash. PA no. I 26: 179-186, 1910. I 2. BEXEDICT, F. G. AND H. ML-RSCIIHAUSER. Energy transformations during horizontal walking.

Curnegie Inst. Wash. Pub. no. 23 I, 1915. II;. BENEDICT, F. G. AND H. S. PARSEENTER. Energy metabolism of women while ascending or

descending stairs. AUK J. PJlpiol. 84: 675-698, 1928. 14. BONJER, F. H. AND J. F. DE WT~X. Personal communication, 195-s.

836 R. PASSMORE AND J. V. G. A. DURNIN Volume 35

Is. BREZINA, E. AND W. HO-R. uber den Energieverbrauch bei der Geharbeit unter dem Einflussverschiedener Geschwindigkeiten und Verschiedener Belastungen. Biochem. Ztschr. 38: 129-153, 1912.

16. BUSCA, L. AND A. GRANATI. 11 lavoro della mietitura. Boll. Sot. ital. biol. sper. 20: 30-34, 1945. 17. CATHCART, E. P., N. V. LOTXIAN AND M. GREENWOOD. A note on the rate of marching and

expenditure of energy in man. J. Roy. Army M. COY@ 34: 297-305, 1920.

18. CATIICART, E. P. AND J. B. ORR. Energy i!%@enditzlre of the Infantry Recrzcit in Training. London: Her Majesty’s Stat. Off., IgIg.

19. CATHCART, E. P., D. T. RICHARDSON AND W. CAMPBELL. Maximum load to be carried by the soldier. J. Roy. Army J&f. Corps 40: 435-443; 41: 12-24, 87-98, 161-178, 1923.

20. CATHCART, E. P. AND F. J. TRAFFORD. Energy expenditure in. minor duties. J. Physiol. 53: 99p, 19209

21. CHLOPIN, G. W., W. JAKSWENKO AND W. WOLSCHINSKY. Weitere Untersuchungen fiber den Einfluss der geistigen Tgtigkeit auf den respiratorischen Gaswechsel und auf den Energieumsstz. Arch. Hyg. 98: 158-175, 1927. ’

22. CHLOPIN, G. W. AND J, L. OKU~WSKY. Einfluss der geistigen Ttitigkeit auf den respiratorischea Gaswechsel bei Menschen. Arch. Hyg. 91: 317-331, 1922.

23. CHRISTENSEN, E. H. Physiological valuation of work in the Nykroppa iron works. EY~O~OWJ~GS

Society Symposium on Fatigue (edited by W. F. Floyd and A. T. Welford). London: Lewis, 1953, PP. 93-108.

24. CHRISTENSEN, E. H. AND P. H&BERG. Physiology of ski-ing. Arbeitsphysiologie 14: 292-303,

IOW* 25. COREY, E. L. Pilot metabolism and respiratory activity during varied flight tasks. J. A$$.

Physiol. I: 35-44, x948. 26. CROWDEN, G. P. Physiological cost of the muscular movements involved in barrow work,

M. Research Council kdustrial Fatigue Research Board no. go, 1928.

27. CROWDEN, G. P. Stair climbing by postmen. The Post, July 26th, 1941, pp. IQ-II. 28. CULLUMBINE, H. Heat production and energy requirements of tropical people. J. A$@. Physid.

2: 640-653, 1950.

29 DELCOURT-BERNARD, E. AND A. MAYER. Recherches sur le mdtabolisme de base. &zn. de physiol. I: 536-579, 1925.

30. DILL, D. B., J. C. SEED AND F. N. MARZULLI. Energy expenditure in bicycling. J. A#. Physiol. 7: 320-324, 1954.

3I. DONALD, K. W. AND ?V. M. DAVIDSON. Oxygen uptake of ‘booted’ and ‘fin swimming’ divers. J. Appl. Physiol. 7: 31-37, x954.

32. DOUGLAS, C. G. Personal communication, 1925.

33. DOUGLAS, C. 6. AND J* S. HALDANE. Capacity of the air passages under varying physical conditions. J. Physiol. 45: 235-238, 1912.

34. DRESSEL, G., K. RARRASCH AND H. SPITZER. Arbeitsphysiologische Untersuchungen bein Schaufeln, Steinetragen und Schubkarreschieben. Zentralbl. Arbeit. siz. Betrieb. 8: 33-48, I954*

35. DROESE, W., E. KOFRANYI, H. KRAUT AND L. WILDEMANN. Energetische Untersuchung der Hausfrauenarbeit. Arbeitsphysiologie 14: 63-81, 1949.

36. DU BOIS, E. F. Basal Aletabolism in Health and Disease. London: Baillihre, Tindall & Cos, =927-

37. DIJ B~Is, E. F. Energy metabolism. Ann. Rev. Physiol. 16: x25--134, 1954. 38. DURNIN, J. V. G. A. Oxygen consumption, energy expenditure and efficiency or” climbing with

loads at low altitudes. J. Physiol. 128: 294, 1955.

$a. DURNIN, J. V. G. A. AND R. G. EDWARDS. Pulmonary ven.tilation as an index of energ>- expenditure. Quart. J. Exper. Plzysiol. Oct. I, x95$.

39. EDHOLM, 0. G., J. G. FLETCHER, E. M. WIDDOWSON AND R. A. MCCANCE. Energy expenditure and food intake of individual men. Brit. J. N&r&on. 9: 286, 1955.

40. EIFF, A. W. AND H. G~~PFERT. Ausmass und Ursachen der Energieumsatz-Vcr~nderungc:n bei g&tiger Arbeit. Ztschr. f. d. ges. exper. Med. 120: 72-85, xg,<z.

41. FARKAS, G. AND J. GELDRICH. uber den Energieverbrauch b&n Orgelspiel. .4rc/:. 11yg. 99: 52-59, 1928.

42. FARKAS, G. AND J. GELDRICIT. uber den Energieverbrauch bei gewerblichcr Arbeit , /,l sir, Hyg. 104: 1-23, 1930.

43. FARKAS, G., J. GELDRICH AND S. LANG. Neuere Untersuchungen iiber den Energicvcrbrauch beim Emten. (17beitsp?2ysio~ogie 5 : 434-462, 1932.

October r955 HUMAN ENERGY EXPENDITURE 837

44* PARKAS, G., S. LANG AND F. LE~~VEY. Weitere Untersuchungen fiber den Energieverbrauch beim Ernten. Arbeitsphysiologie 5 : 569-596, 1932.

45 FLEISCH, A. Le m&abolisme basal standard et sa dbtermination au moyen du “Metabocalcu- lator.” Helvet. med. acta 18: 23-44, 1c)p.

46. Food and Agriculture Organization of the United Nations. Calorie requirements. hi0 A$&& tional Stzldies no. 5, 1950, Washington.

47. Food and Agriculture Organization of the United Nations. Joint F.&)/WHO .&pert Corrz&tee on Nutrition. 4th report, 1954.

48. FOX, R. H. Energy expenditure of Africans engaged in various rural activities. Thesis for Ph.D., London Univ., 1953.

49. GARRY, R. C., R. PASSMORE, G. M. WARNOCK AND J. V. G. A. DURNIN. Expenditure of energy

and the consumption of food by miners and clerks, Fife, Scotland, 195 2. M. Research Cowtci~

Spec Rep. Ser. No. 289. Her Majesty’s Stat. Off., 1955.

50. GELDRICH, J. Uber den Energieverbrauch beim Reiten. B&hem. Ztschr. 188: 1-14, 1927.

51. GIDDINGS, G. Motility of school children during sleep. Am. J. Physio!: 127: 480-485, 193~~.

52. GLASER, H. Untersuchungen tiber die Schlagarbeit mit Hgimmern oder Axten. Arbeitsphysiologie 14: 448-459, qw

53. GLASOW, VV. AND E. A. MUELLER. Das Gehen auf verschiedenen Boden. Arbeitsphysiologie 14: 319-321, 19%

54. GLASOW, W. AND E. A. MUELLER. Das Tragen Schwerer S%ke in der Ebene und auf einer Treppe. Arbeitsphysiolugie 14: 322-327, 1951.

5s. GRANATI, A. 11 lavoro de1 selciatore. Boll. Sot. ital. biol. sper. 20: 346-347, rgqj. 56. GRANATI, A. 11 lavoro dei muratori. Boll. Sot. ital. biol. sper. 22: 267-268, 1946. 57. GRANATI, A. AND L. BUSCA. 11 costo energetic0 de1 lavoro nelle miniere di carbone in carbonia.

Qzladerni della Nzctrizione 8: 1-34, 1941. 58. GRANATI, A. AND L. BUSCA. 11 lavoro della trebbiatura. Boll. Sot. ital. biol. sper. 20: p-53,

1945 59. GRAY, E. L., F. C. CONSOLAZIO AND R. M. KARK. Nutritional requirements for men at work

in cold, temperate and hot environments. J. Appl. Physiol. 4: 270-275, rggr. 60. GREENWOOD, M., C. HODSON AND A. E. TE~B. Report on metabolism of female munition work-

ers. Proc. Roy. Sot., London, s. B. 91: 62-82, 1919.

61. GROLLMAN, A. Physiological variations in cardiac output of man. XI. Pulse rate, blood pressure, oxygen consumption, arterio-venous oxygen difference and cardiac output of man during normal nocturnal sleep. ,471~. J. Physiol. 95: 274-284, xgp.

62. HETTINGER, TH. AND W. WIRTHS. Der Energieverbrauch beim Hand- und Motorpltigen. Arbeitsphysiologie 15: 41-46, 1953.

63. HETTINGER, TH. AND W. WIRTHS. Uber die kiirperliche Beanspruchung beim Hand- und Maschinemelken. Arbeitsphysiologie 15 : 103-1 IO, 1953.

64. HORVATH, S. M. AND H. GOLDEN, Men performing a standard amount of work in low ambient temperatures. J. cl&. Investigation 26: 31 I-319, 1947.

65. JOHANSSON, J. E. Ueber die Tagesschwankungen des Stoffwechsels und der Kiirpertemperature in niichternem Zustande und vollstgndige Muskelriihe. Skandinav. Arch. f. Physiol. 8, 85-142, 1898.

66. JOHNSON, H. M. AND G. E. WEIGAND. Measurement of sleep. Proc. Pa. Acad. SC. 2: 43-48, x927. 67, HAGAN, E. M., P. DOLGIN, P. M. KAPLAN, C. 0. LINETZKAJA, J. L. LUBARSKY, M. F. NEUMA~,

J, J, SEMERNIN, J, S. STARCH AND P. SPILBERG. Physiologische Vergleichsuntersuchung der Hand-und Fleiss-(Conveyer) Arbeit. Arch. Hyg. IOO: 335-366, 1928.

68. KAHN, J. I,., VV. IV. KOTSCIIEGINA AND T. A. ZWINOGRODSKAJA. Uber die energetische Charak- teristik der landwirt-schaftlichen Arbeiten. Arbeitsphysiologie 6: 585-594, 1933.

68a. KABONSKY, G. Untersuchungen beim Holztransport mit Schlitten im winterlichen Hoch- gebirge. Arbeitsphysiologie 15 : 47-56, 1953.

69. QRPOVICH, P. V. AND C. J. HALE. Energy expended in administering artificial respiration. J. Appl. Physiol. 4: 467-471, 1951.

70, KARPOVI~H, P, 17. ANI N. MILLMAN. Energy expenditure in swimming. Am. J. Physiol. 142:

140-144, 19440 71. KARPOVICH, P, V. AXE R. R. RONKIN. Oxygen consumption for men of various sizes in the

simulated piloting of a plane. Am. J. Physiol. 146: 394-398, 1946. 72. KARRASCH, K. Der Energieumsatz beim Lastentragen auf der Treppe. Arbeitsphysiologie 14:

492-498,1952.

838 R. PASSMORE AND J. V. G. Al. DURNIX ‘C.IoLwne 35 I

KARVONEN, M. J. AND 0. TURPEXNES. Consumption and selection of food in competitive lumber work. J. &pl. Physiol. 6: 603-612, 1954. KENNEDY, T, F. Investigation of energy expended on the exercises of the physical training tables for recuits of all arms, J. Roy. Army M. Corps 61: 1-17, 108-118, 185-192, 257-261,

“933. KEYS, A. Calorie requirement of adult man. ilTutvitian Abstr. & Rev. Ig: I-IO, 1949.

KEYS, A., J. BROZEK, A. HENSCHEL, 0. MICKELSEN AND H. L. TAYLOR. Biology of Hzw1aq2 Starvation. Minneapolis, Minn. : Univ. Minnesota Press, 1950, KLEIBER, h/z. Body size and metabolic rate. Physiol. Rev. 27 : gr 1-541, 1947. KLEITMAN, N. Sleep. Physiol. Rev. 9: 624-665, rpg. KLEITJAAN, N., N. R. COOPERMAN AND F. J. MUT,LIN. Physiology of sleep. IN. Motiliiy and body temperature during sleep. 11~. J. Plzysiol. 105: 574-584, 1933. KOFRANYI, E. AND H. F. MICHAELIS. Ein tragbarer Apparat zur Bestimmung des Gasstoff- wechsels. .4rbeitsphysiologie I I : 14S-150, r 940. K~MIVEERELL, B. Die Schaufelarbeit in gubiickter Haltung. Arbeitsphysiologie I : 278-295, 1929.

LAMBERTSEN, C. J., R..H. KOUGH, D.Y. COOPER, G.L. EMMEL, H. H. LOESCHEKE AND C. F. SCHMIDT. Oxygen toxicity. Effects in man of oxygen inhalation at I and 3.5 atmospheres upon blood gas transport, cerebral circulation and cerebral metabolism. J. &@. IV2$ol. 5 :

471-486, 1953. LANGWORTHY, C. F. AND f-f. G. BAROTT. Energy expenditure in household tasks. Am. J. Physiol. 52: 400-408, 1$20. LANGWORTHY, C. F. AKD H. G. BAROTT. Energy expenditure in sewing. Am. J. Physiol. 59: 376-380, 1922. LEGUN, A. F. AND 0. I?. XOETSCHANOWA. uber den 24 Stiindigen Energieverbrauch von Kin- dem im Schulpflchtigen Alter 8-14 Jahre. Problems of Nutrition, &foscow 4: 43-60, 1935. LEHMANN, G. Praktische Arbeitsphysiologie. Stuttgart : Thieme, 1953. LEHMAIL'N, G., E. A. MUELLER AND H. SPITZER. Der Calorien ‘bedarf bei gewerblichcr Arbeit. Arbeitsphysiologie 14: 166-235, 1950. LIEBEUANN, L. Energiebedarf und mechanisches Equivalent der geistigen Arbeit. Biochem. Ztschr. 173: ISr-189, 1926.

58~~. LILJESTRAND, G. AND J. LIXDHARD. Zur Physiologie des Ruderns. Skadnav. Arch. f. Physiol. 3g:215-235,192o.

@. LILJESTRAND, G. A&? N. STENSTR~~M. Studien iiber diePhysiologie des Schwimmens. Skandinav. Arckf. PI2ysiol. 39: 1-63, Igzo.

go, LOEWY, A. Ueber den Einfl nebst Beobachtungen tiber 1

ss einiger Schlafmittel auf die Erregbarkeit des Athemcentrums ie Intensitgt des Gaswechsels im Schlafe beim ulenschen. HZ&z.

Wchnschr. 28: 434-438, 1891. 91. LOEWY, A. AND H. SCHROETTER. uber den Energieverbrauch bei musikalischer Betgtigung.

PfEtiger’s Arch. ges. Plzysiol. 2x1: 1-63, 1926. p. LUNDGREN, N. P. V. Physiological effects of time schedule work on lumber-workers. Ada.

p?2ysiol. scandinav 13, suppl. 41~ 1946. 93. LUPTON, H. Effects of speed on the mechanical efficiency of human muscular movement.

J. PJ2ysiol. 57: 337-349, 1923. 94. MAGNUS-LEVY, A. Ueber die Griisse des respiratorischen Gaswechsels unter dem Einffuss der

Xahrungsaufnahme. Pfitiger’s Arch. ges. Physiol. 55: 1-126, 1894. 95. ~~~AD@vA, K. AND Ii. PASSMORE. Unpublished results. 95. ~~IAH'ADEVA, K., R. PASSMORX AND B. WOOLF. Individual variations in metabolic cost of stand-

ardized exercises: effects of food, age, sex and race. J. Physiol. I 21: 225-231, 1953. 97. MAISELS, L.I.,N.P. WASCHETKO,M.G.KATSCHALAAND E. A. SJELJENSKY. UberNahrungsra-

tionen und Hygienische Erntihrungsweise von Hguern, Befestigern und Maschinisten van Bohrmaschinen. Problems of N&rition, Moscow 4 : I B-30, 1935.

98. MARGARIA, R. Sulla fisiologia, e specialmente sul consumo energetico, della marcia c della corsa a varie velocita ed inclinazioni de1 terreno. A tti dei Lincei 7 : 299-368, 1938.

(jr), MARRO, F., V. MILANI AND E. C. VIGLIANI. Studio sul consurno energetic0 delle dattilografc con macchina meccanica cd elettrica. Med. Zavoro 45: I 2-28, 1954.

IQO, A&t~~~~, E. D. AND F. G. BEXEDICT. Effect of sleep on human basal metabolism with particular reference to south Indian lvotnen. An2. J. Physiol. 108: 377-383, 1934.

131. MOSS, K. N Energy expenditure of coal-miners during work, Tr. Inst. Miwbz,g EIQ$. C;* l ( 0.

I32--‘I433 x935*

October rg55 HUMd4N ENERGY EXPENDITURE 839

102.

103.

104. 105.

106. 107.

108.

109.

110.

III.

112.

113.

x 14.

115.

116. 117.

118.

119.

120.

121.

122.

123.

I 24.

125.

126.

127.

128. 129.

130.

MUELLER, E. A. Physiological basis of rest pauses in heavy work. Qwrt. J. Expw. Phy~id. $3:

205--215, 1953* MUELLER, E. A. AND H. FRANZ. Energieverbrauchsmessungen bei beruflicher Arbeit mit einer verbesserten Respirations-Gasuhr. Arbeitsphysiologie 14: 499-504, 1952.

NECHELES, H. Basal metabolism in Orientals. Am. J. Physiol. 91: 661-663, 1929. NELSON,N. A., W. B. SHELLEY,~. M. HORVATH, L. ?~.EICHNAAND T.F.Hxrm.Influenceoi clothing, work and air movement on the thermal exchanges of acclimatized men in various hot environments. J. Clin. Investigation 27: 209-216, 1948. OGASAWARA, M. Energy expenditure in walking and running. J. Physiol. 81: 255-264, 1934.

ORR, J. B. AND J. P. KINLOCH. Influence of diet on the energy expenditure in work. J. Roy. Army M. Corps 36: h-86, xgx. ORR, J. B. AND I. LEITCII. Determination of calorie requirements of man. Nutrition A&. & Rev. 7: 509-529, 1938. ORSINI, D. AND R. PASSMORE. Energy expended carryin, (J loads up and down stairs. Experi- ments using the KofranyiXichaelis calorimeter. J. Physiol. I 15: gpIoo, IgSI. PASSMORE, R., A. P. MEIKLEJOHN, A. D. DEBAR AND R. K. THOW, Analysis of the gain im

weight of overfed thin young men. B&t. J. Nutrition g: 27, rgss.

PASSMORE, R., J. G. THOMSON AND G. M. WARNOCK. Balance sheet of the estimation of energy intake and energy expenditure as measured by indirect calorimetry. BP& J. Ntitrition 6: 253-

264, WP. PHILLIPS, P. G. &Xetaholic cost of common West African agricultural activities. J. T~op. *!!ea”. 57: 12-20, 1gs4.

PICKWORTH, F. A. Basal metabolism as determined by respiratory exchange. Proc. Roy. Sot., London, s. B. IOI: 163-185, 1927. PLAYFAIR, L. The food of man in relation to his useful work. Proc. Roy. Imt. Great Britaift 3 : 43I-433,IW POLLACK, H., C. E. FREXCH AND G. H. BERRYMAN. Calnries expended in military activities. Bull. U.S. Army 1M. Dept. 74: 110-114, 1944. RAMZIN, S. Energy balance in soldiers of Yugoslav army. Voj.-san. pregled 5: 131-144, 194% RICHARDSON, D. T. A&I W. CAMPBELL. Report OH the Investigation of the Energy Expenditure q/ the British Soldier irt Indict. Calcutta : Govt. of India Press, 1927. ROBERTSON, J. M. AND D. D, REID. Standardsfor basal metabolism of normal people in Britain. Lancet 1: 940-943, x952.

ROBINSON, S. Effect of body size upon energy exchange in work. &z. J. Physiolc. 136: 363-368,

1942. ROSENBLUM, D. E. Untersuchungen iiber den respiratorischen Gastoffwechsel und Energievtlr- brauch bei geistiger Arbeit. ArbeitspJiysiologie 6: 214-234, Ig32. SCHNEIDER, E. C. AND P. V. KARPOVICH. Physiology of illzt.scular A&vi/y (3rd cd.). Phil~- delphia and London: Saunders, 1948, p. 61. SELTZER, C. C. Body build and oxygen metabolism at rest and during exercise. Anl. J. Physiol. x29: 1-13, 1940. SIMONSON, E. Rationalisierung industrieller Arbeit nach physiologischen Gesichtspunktcn. Arbeitsphysiologie I : 503-563, 1929. TAYLOR, C. M., x/I. W. LADKB, M. E. ROBERTSON AND G. MACLEOD. Energy expenditure for quiet play and cycling of boys 7 to 14 years of age. J. Nutrition 35: 511-521, 1948. TAYLOR, C. M, 0. I?. 1%~ A~TD A. B. CALDWELL. Energy expenditure of g to II year-old boys. and girls (I) standing drawing and (2) dressing and undressing. J. NtitGtion 36 : I 23- x3 I !

19489 TAYLOR, C.M.,O.F.PYE, L4. B. CALDWELLAND E.R. SOSTMAN. Energy expenditure of boys and girls g to I I years of age (I) sitting listening to the radio (phonograph), (2) sitting singing, and (3) standing singing. J. hT&%ion 38: I-IO, 1949. TIGERSTEDT, C. AND H. OLIN. Der Stoffwechsel bei einigen leichteren Berschzftigungen und Gewerben. Skandinav. Arch. f. Pltysiol. 45 : 82-94, 1924. TURNER, D. Energy cost of some industrial operations. Brit. J. Indust. Med. 12: 237, 1955. WACHHOLDER, K. Energiebedarf fiir Hijrperliche ,4rbeit untl Erhaltungsumsatz. inJli&eF’s Arch. ges. Physiot. 250: 534-551, xg48. WEATHERHEAD, E. L. AND D. B. THOWON. Energy expenditure of scrubbing. Arbeik.~p~zys~nZn.~~~ 6: jgj-606, 1933.

$40 R. PASSMORE AND J. V. G. A. DURNIN Vutzfme 35

131. WEWIG, K. Beitrgge zur Physiologie des Schaufelns. Arbeitsphysiologie I : 154-186, 1g2g.

x32. WDDOWSON, E. M., 0. G. EDHOLX AND R, A. MCCANCE. Intake and energy expenditure of cadets in training. B&t. J. Ntirition 8: 147-155, x954.

I 33. WOHLFEIL, ‘1’. uber den Energieverbrauch bei sportlicher Rorperarbeit (Kanufahren). Arch. HYg. 100:393-411, 1928.

134. WOLPERT H. Ueber die Kohlensure -und Wassendampf-Ausscheidung des Menschen bei gewerblicher Arbeit und bei Ruhe. Arch. Hyg. 26: 68-108, 1896.

x35. WOOLF, B. Statistical aspects of dietary surveys. Proc. Nutrition sot. 13: 82-94, 1954. 136. WYNDHAM, C. IX, W. v. D. M. BOUWER, M. G. DEVINE AND H. E. PATERSON. Preliminary

investigations in the efTfects of saturated air temperatures, wind velocities and rates of energy expenditure on non-European labourers. Report to consulting engineers, Rand Mines Group, Johannesburg, r gg I.

137. ZUNTZ, L. U&mtichungen i&&r delt Guswechsel tin& Energiezmsatzdes Radfohrers. Berlin: Hirsch- wald, 1899.

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