1RHR and VO2-max

RUNNING HEAD: RHR AND VO2-MAX

The Relationship between RHR and VO2-max

Brian Danley

KIN 175

4/24/2009

San Jose State University

2RHR and VO2-max

The Relationship between RHR and VO2-max

Cardiovascular health is typically assessed by measuring the heart rate and aerobic

capacity of an individual. Specifically, resting heart rate (RHR) and maximal oxygen

consumption (VO2-max) are two physiological parameters which indicate cardiovascular fitness

level. The RHR is the heart rate during a resting or sedentary state, expressed as beats per

minute (bpm). VO2-max is the maximal rate of oxygen consumption by the body during

exercise, usually expressed as milliliters of oxygen per kilogram bodyweight per minute

(ml/kg/min).

In a clinical environment, VO2-max can be determined using a graded exercise test

protocol in which exercise intensity is progressively increased. The concentration of oxygen and

carbon dioxide inspired and expired, respectively, is measured as workload incrementally

increases until maximal cardiovascular effort is induced. VO2-max is identified when the

consumption of oxygen remains static despite continual increases in exercise intensity.

However, determining VO2-max in this manner is impractical in a gym environment due to such

factors as large equipment expense, lack of floor space and high risk of subject noncompliance.

Instead, VO2-max can be determined via a sub-maximal test at reduced workload intensities, thus

significantly reducing subject noncompliance. Readily accessible gym equipment including a

heart rate monitor and treadmill can be used.

Several research studies have investigated the differences in RHR and VO2-max between

the genders. For example, some research studies have shown that females tend to have lower

VO2-max capacities than males (Harms, 2005 & Olfert et al., 2004). Additionally, other research

studies have supported the finding that VO2-max capacity declines with age (Amara et al., 2000

3RHR and VO2-max

& Shephard, 2008). But there is a lack of research that focuses on the relationship between RHR

and VO2-max. Research data has indicated that long-distance runners are characterized by low

RHR and high VO2-max (Dasqupta, Mukhopadhyay & De, 2000). Thus, this study

hypothesizes that there is a relationship between RHR and VO2-max. The purpose of this study

was to examine the nature and strength of the relationship between RHR and VO2-max.

METHODS

Subjects. The personal training fitness manager of Arrillaga Sports and Recreation

Center (ASRC) at Stanford University had advertised via posted flyers around campus the offer

of free fitness assessments (a $20 value) at ASRC during the period of March 2nd thru April 6th,

2009 for the first twenty-five people who were willing to have their RHR and VO2-max

determined. A calendar page containing multiple available time periods throughout each day

was also posted for those who were interested. Time periods consisting of 30-minute durations

were reserved by signing in whichever slot was available and/or convenient. Only one subject

could be tested at a time. The flyer indicated the data collected would be used in a research

study. Each person who wanted to participate had provided an email address for contact

purposes. In addition, each individual voluntarily signed a consent form before a fitness

assessment was performed. The participants in this study consisted of 14 males and 11 females

who were (median ± SD, N = 25) 43 ± 17 yrs of age and 184 ± 30 lbs bodyweight. Subjects

included faculty and staff members, students and people within the Stanford community.

Study design. Any person regardless of age, gender, ethnicity, motivation level, etc. was

invited to participate in the study. Sample size was chosen without knowing beforehand the

reliability of the performance measures. Each subject was provided the same pre-exercise test

4RHR and VO2-max

instructions via email. The instructions specified to: avoid food, alcohol, caffeine, and nicotine

three hours before the VO2-max test; avoid strenuous exercise on test day; wear running shoes

and comfortable sweat pants or shorts; continue taking medication as prescribed (if applicable);

bring the medication list (if applicable); and drink ample fluids within one day of the test.

A verbal interview with each subject was conducted in the fitness training office at ASRC

as part of the fitness assessment in order to record relevant demographic variables including

gender, age and bodyweight. Bodyweight was measured using a calibrated precision sensor

monitored by Microfit HealthWizard®, a computer software program designed for recording,

analyzing and tracking purposes. Data collection of RHR was obtained by utilizing an

automated blood pressure monitor. VO2-max was calculated based on exercise heart rate.

Subjects were not told what constitutes good values for RHR and VO2-max. Hence, no goals

were specified to the participants in the study.

RHR test. The RHR was assessed utilizing a clinically-validated wrist Lifesource®

digital blood pressure monitor. Each subject was directed to sit down comfortably for the

duration of five minutes before given the instruction to extend and rest the left arm with palm

facing up onto a supporting surface at approximately the level of the heart. The blood pressure

monitor was then applied one centimeter proximal to the wrist crease. The start button was then

pushed to activate the monitor as it automatically compressed to gauge RHR. The RHR data

was recorded as soon as it was displayed on the monitor.

VO2-max test. In order to assess VO2-max, exercise heart rate was measured utilizing

the world leader Polar® heart rate monitor. The monitor consists of an electrode transmitter

within a rubberized material and an elastic strap which can be adjusted to fit the torso of each

5RHR and VO2-max

subject. In addition, a wrist watch receiver, worn by the recorder, was used to monitor real-time

exercise heart rhythm. Each subject was directed to moisten the electrode-plate backing with

several drops of water (to accentuate contact conductivity with the skin) and place the monitor

underneath the shirt at the level of the sternum before tightening the elastic band.

Objective exercise heart rates were calculated and recorded for each subject prior to

beginning two trials (one at low-intensity and one at high-intensity exercise level). Calculation

involved the use of the Karvonen formula for two trials:

HRR 1=¿¿∗0.60+RHR (Low-intensity exercise)

HRR 2=¿¿∗0.80+ RHR (High-intensity exercise) where HRR is heart rate reserve

and 0.60 and 0.80 are the constant decimals for low-intensity and high-intensity exercise,

respectively as recommended by American College of Sports Medicine (ACSM) for most

individuals (ACSM, 2006).

Each subject, having the heart rate monitor on, was directed to a treadmill dedicated for

the purpose of the study. Initially, each participant was told to select whichever % grade and

speed desired with the caveat that % grades inputted must be in 2.5% increments (i.e. 0, 2.5,

5,etc.). Once grade and speed were selected, the subject’s heart rate was monitored. As the

exercise heart rate increased, the subject was told by the data recorder when to increase the

exercise intensity level. Either grade or speed was increased depending on individual preference

until the desired HRR1 for trial one and HRR2 for trial two was achieved. The duration of each

trial was between five to ten minutes. The grade and speed for each trial, designated as [GR1

and SP1] for trial one and [GR2 and SP2] for trial two was determined based on HRR1 and

HRR2. Next, the exercise intensity level of each trial was calculated using the designations of

6RHR and VO2-max

MET1 and MET2 for metabolic equivalents. METs are a way to express oxygen uptake relative

to resting values and can be calculated as:

METs = VO2 (ml*kg-1min-1) / 3.5.

Using Table 1 and the following two formulas, respective trial speeds and grades were

interpolated in order to determine MET1 and MET2:

MET 1=[SP 1−SP1 (below ) ]

[ SP1 (above )−SP 1 (below ) ]∗[ MET 1 (above )−MET 1 (below ) ]+MET 1(below)

MET 2=[SP 2−SP 2 (below ) ]

[ SP 2 ( above )−SP 2 (below ) ]∗[MET 2 ( above)−MET 2 (below ) ]+MET 2(below)

SP1 (above) and SP1 (below) refer to values within the tan area of Table 1 above and

below observed speed SP1, respectively.

SP2 (above) and SP2 (below) refer to values within the tan area of Table 1 above and

below observed speed SP2, respectively.

MET1 (above) and MET1 (below) refer to table values within the white area of Table 1

corresponding to SP1 (above) and SP1 (below) at GR1, respectively.

MET2 (above) and MET2 (below) refer to table values within the white area of Table 1

corresponding to SP2 (above) and SP2 (below) at GR2, respectively.

7RHR and VO2-max

TABLE 1. METs as a function of grade and speed (ACSM, 2006, Tables D-2 & D-3, p 292).

METS

              MPH            % GRADE 1.7 2 2.5 3 3.4 3.75 5 6 7 7.5 8 9 10

0 2.3 2.5 2.9 3.3 3.6 3.9 8.6 10.2 11.7 12.5 13.3 14.8 16.32.5 2.9 3.2 3.8 4.3 4.8 5.2 9.5 11.2 12.9 13.8 14.7 16.3 18

5 3.5 3.9 4.6 5.4 5.9 6.5 10.3 12.3 14.1 15.1 16.1 17.9 19.77.5 4.1 4.6 5.5 6.4 7.1 7.8 11.2 13.3 15.3 16.4 17.4 19.4  10 4.6 5.3 6.3 7.4 8.3 9.1 12 14.3 16.5 17.7 18.8    

12.5 5.2 6 7.2 8.5 9.5 10.4 12.9 15.4 17.7 19    15 5.8 6.6 8.1 9.5 10.6 11.7 13.8 16.4 18.9      

17.5 6.4 7.3 8.9 10.5 11.8 12.9        20 7 8 9.8 11.6 13 14.2        

22.5 7.6 8.7 10.6 12.6 14.2 15.5        

25 8.2 9.4 11.5 13.6 15.3 16.8              

Finally, VO2-max was calculated using the following linear formula:

VO 2 max=3.5∗MET 2+3.5 ( MET 2−MET 1 )(MHR−HRR 2) /(HRR 2−HRR 1)

where MHR = 220 – age.

Statistical analyses. All of the data including age, gender, bodyweight, RHR, and VO2-

max was collected and inputted on a spreadsheet using the Statistical Package for the Social

Sciences (SPSS version 17.0, SPSS, Chicago, IL, USA) statistics software program. Descriptive

statistical analyses included the following: frequency distribution tables (FDTs); central

tendency (CT) including range and standard deviation (SD); frequency distribution curve; linear

probability of RHR and VO2-max; VO2-max validity; and RHR and VO2-max reliabilities. The

nature and strength of the relationship between RHR and VO2-max was determined by using the

Pearson correlation. RHR and VO2-max were the primary variables examined for their

relationship. Age, gender and bodyweight were three additional variables considered relevant to

8RHR and VO2-max

the main investigation and the analyses are in the Tables & Figures section. Correlation

strengths were interpreted using the following thresholds:

HIGH = ±0.8 to ±1.0

MOD HIGH = ±0.6 to ±0.79

MOD = ±0.4 to ±0.59

LOW = ±0.2 to ±0.39

NO RELATION = 0 to ±0.19.

The concurrent validity of VO2-max was assessed by comparing the values from the

sample data VO2-max with those from another group. RHR and VO2-max reliabilities were

assessed by internal consistency (the original sample data set was split into even and odd cases).

Regression analysis. Regression analysis of VO2-max with respect to RHR was done to

identify the presence of any outliers (Fig 1). Two outliers at the bottom of the left graph were

located and removed as shown in the accompanying right graph.

FIGURE 1—Scatterplot of VO2-max as a function of RHR.

9RHR and VO2-max

The scatterplots of age (Fig 12) and bodyweight (Fig 13) as a function of VO2-max are in

the Tables & Figures section of this paper.

Error check. A FDT encompassing all of the variables was generated to check for any

errors or missing data. No errors were observed although two cases were coded as missing for

VO2-max (the two outliers previously discussed). The missing data is clearly indicated in Table

2 under the VO2-max column. Individual variable FDTs are in Tables 16 thru 20 in the Tables

& Figures section of this paper.

TABLE 2. Frequency distribution of all of the variables.

Statistics

age (yrs) M = 0; F = 1 bodyweight (lbs) RHR (bpm)

VO-2 max

(ml/kg/min)

VO-2 max (norm)

(ml/kg/min)

N Valid 25 25 25 25 23 25

Missing 0 0 0 0 2 0

Table 3 indicates a majority of the subjects in the study were male.

TABLE 3. Frequency distribution of genders.

M = male; F = female

Frequency Percent Valid Percent

Cumulative

Percent

Valid F 11 44.0 44.0 44.0

M 14 56.0 56.0 100.0

Total 25 100.0 100.0

Norm-reference data. Tables 4 and 5 each contain VO2-max data as a function of age

and gender [Aerobics Center Longitudinal Study (ACLS) from 1970 to 2002 at The Cooper

10RHR and VO2-max

Institute in Dallas, Texas]. The 50th percentile VO2-max values for corresponding data set ages

and genders were inputted and labeled as VO2-max normal in the SPSS spreadsheet in order to

perform a norm-reference comparison analysis.

TABLE 4. Percentile values for maximal aerobic power in men (ml*kg-1min-1) (ACSM,

2006, Table 4-8, p 79).

MALE VO2-max

        AGE (yr)     PERCENTILE 20 - 29 30 - 39 40 – 49 50 - 59 60+  90 55.1 52.1 50.6 49 44.2  80 52.1 50.6 49 44.2 41  70 49 47.4 45.8 41 37.8  60 47.4 44.2 44.2 39.4 36.2  50 44.2 42.6 41 37.8 34.6  40 42.6 41 39.4 36.2 33  30 41 39.4 36.2 34.6 31.4  20 37.8 36.2 34.6 31.4 28.3  10 34.6 33 31.4 29.9 26.7

TABLE 5. Percentile values for maximal aerobic power in women (ml*kg-1min-1) (ACSM,

2006, Table 4-8, p 79).

FEMALE VO2-max

        AGE (yr)     PERCENTILE 20 - 29 30 - 39 40 – 49 50 - 59 60+  90 49 45.8 42.6 37.8 34.6  80 44.2 41 39.4 34.6 33  70 41 39.4 36.2 33 31.4  60 39.4 36.2 34.6 31.4 28.3  50 37.8 34.6 33 29.9 26.7  40 36.2 33 31.4 28.3 25.1  30 33 31.4 29.9 26.7 23.5  20 31.4 29.9 28.3 25.1 21.9  10 28.3 26.7 25.1 21.9 20.3

11RHR and VO2-max

Study data. Table 6 contains the data set taken from SPSS that was used for analysis.

Note: Gender is coded as male = 0 and female = 1.

TABLE 6. Fitness assessment data.

subject age

gender

bodyweight RHR

VO_2_max

VO_2_max_norm

1 57 1 205 83 20.4 29.92 54 1 178 80 27.48 29.93 25 1 193 66 33.59 37.84 30 1 130 54 47.61 34.65 83 0 208 56 24.59 34.66 79 0 195 66 38.03 34.67 66 0 175 53 36.57 34.68 29 0 141 68 37.4 44.29 43 0 214 69 42.67 41

10 58 0 238 58 37.53 37.811 43 1 139 61 35.92 3312 41 0 198 65 39.9 4113 62 0 187 68 34.47 34.614 62 1 156 74 28.56 26.715 29 0 184 76 39.75 44.216 58 1 155 73 32.42 29.917 34 0 215 64 38.6 42.618 23 1 135 67 38.23 37.819 36 0 194 58 44.78 42.620 47 0 187 67 39.56 4121 43 1 166 74 35.67 3322 26 0 158 63 41.2 44.223 56 0 185 67 39.55 37.824 46 1 153 69 31.34 3325 32 1 125 72 36.35 34.6

12RHR and VO2-max

RESULTS

Descriptive statistics. Since most of the variables are continuous (e.g. age and RHR) or

categorical (e.g. gender), the descriptive statistics used to summarize the information were

percentages from FDTs and frequencies from crosstabulations. Other descriptive statistics used

to summarize were CT analyses for ratio (e.g. bodyweight) and interval (e.g. VO2-max)

variables. The frequency of each gender as a function of age is indicated in Figure 2. The bar

chart is shown rather than the crosstab table to clearly compare males and females for age

frequency distribution. The sample population is characterized by a slight majority of males

throughout the age range.

FIGURE 2—Frequency distribution of each gender as a function of age.

Note: Male=0; Female=1.

The frequency of each gender as a function of RHR is indicated in Figure 3. Again, the

bar chart is shown rather than the crosstab table to clearly compare males and females for RHR

13RHR and VO2-max

frequency distribution. The figure indicates there were more females than males within the

sample that had a RHR > median of 67 bpm.

FIGURE 3—Frequency distribution of each gender as a function of RHR.

Note: Male=0; Female=1.

Central tendency. Table 7 indicates RHR and VO2-max have a relatively normal

distribution as the mean and median of each variable are not significantly different. In addition,

VO2-maxnormal can be seen in this table having a more significant differentiation between the

average and the middle values.

14RHR and VO2-max

TABLE 7. Central tendency and variability analysis.

Statistics

age (yrs) bodyweight (lbs) RHR (bpm)

VO-2 max

(ml/kg/min)

VO-2 max (norm)

(ml/kg/min)

N Valid 25 25 25 23 25

Missing 0 0 0 2 0

Mean 46.48 176.56 66.84 37.2687 36.6000

Median 43.00 184.00 67.00 37.5300 34.6000

Std. Deviation 16.626 29.792 7.609 4.73037 5.01946

Range 60 113 30 20.13 17.50

Minimum 23 125 53 27.48 26.70

Maximum 83 238 83 47.61 44.20

Figures 4 and 5 graphically illustrate the slightly negatively-skewed (mean < median)

distribution shapes of the RHR and the VO2-max curves, respectively. The average RHR of

66.84 bpm is slightly less than the middle value of 67.00 bpm. The average VO2-max of 37.27

ml/kg/min is slightly less than the middle value of 37.53 ml/kg/min.

FIGURE 4—RHR frequency distribution.

15RHR and VO2-max

FIGURE 5—VO2-max frequency distribution.

Figure 6 graphically illustrates the slightly positively-skewed (mean > median)

distribution shape of the VO2-maxnormal curve. The average VO2-maxnormal of 36.6 ml/kg/min is

greater than the middle value of 34.60 ml/kg/min.

FIGURE 6—VO2-maxnormal frequency distribution.

16RHR and VO2-max

Linearity analysis. Figure 7 graphically illustrates the trend in linearity of RHR, VO2-

max and VO2-max normal.

FIGURE 7---Expected RHR, VO2-max and VO2-maxnormal linear probability curves.

17RHR and VO2-max

Main question: Is there a relationship between RHR and VO2-max?

The nature and strength of the relationship between RHR and VO2-max was determined

by using the Pearson correlation. The Pearson correlation between RHR and VO2-max is

indicated in Table 8 as rxy= -0.600. This value is considered to be of moderately-high strength.

The negative sign indicates the inverse relationship between the data of the two variables. That

is, as RHR increases, VO2-max decreases and vice-versa. This result supports the hypothesis

that a relationship exists between RHR and VO2-max.

TABLE 8. Correlation between RHR and VO2-max.

Correlations

RHR (bpm)

VO-2 max

(ml/kg/min)

RHR (bpm) Pearson Correlation 1 -.600**

Sig. (2-tailed) .002

N 25 23

VO-2 max (ml/kg/min) Pearson Correlation -.600** 1

Sig. (2-tailed) .002

N 23 23

**. Correlation is significant at the 0.01 level (2-tailed).

Figure 8 supports the relatively strong correlation between RHR and VO2-max.

18RHR and VO2-max

FIGURE 8---Linearity curve of RHR as a function of VO2-max.

Related question: Is there a relationship between age and VO2-max?

The Pearson correlation between age and VO2-max was found to be rxy= -0.387. This

value is considered to be of low strength. The negative sign indicates the inverse relationship

between these two variables. That is, as age increases, VO2-max decreases slightly. The

correlation table (Table 21) and figure (Figure 12) of age as a function of VO2-max is in the

Tables & Figures section of this paper.

Related question: Is there a relationship between gender and VO2-max?

The Point Biserial correlation between gender and VO2-max was found to be rxy= -0.484

(Table 9). This value is considered to be of moderate strength. The negative sign is irrelevant

here as gender is a dichotomous variable but the magnitude indicates significance of gender with

respect to VO2-max.

19RHR and VO2-max

TABLE 9. Correlation between gender and VO2-max

Correlations

M = 0; F = 1

VO-2 max

(ml/kg/min)

M = 0; F = 1 Pearson Correlation 1 -.484*

Sig. (2-tailed) .019

N 25 23

VO-2 max (ml/kg/min) Pearson Correlation -.484* 1

Sig. (2-tailed) .019

N 23 23

*. Correlation is significant at the 0.05 level (2-tailed).

Table 10 provides support for the gender-VO2-max correlation as exhibited by small SDs.

TABLE 10. Compare means between gender and VO2-max substantiates the moderate correlation due to small SDs. Report

VO-2 max (ml/kg/min)

M = 0;

F = 1 Mean N Std. Deviation

0 39.2315 13 2.66547

1 34.7170 10 5.69431

Total 37.2687 23 4.73037

Related question: Is there a relationship between bodyweight and VO2-max?

The Pearson correlation between bodyweight and VO2-max was found to be rxy= 0.120

indicating no relation between these variables. The correlation table (Table 22) and figure

20RHR and VO2-max

(Figure 13) of bodyweight as a function of VO2-max is in the Tables & Figures section of this

paper.

Validity analysis. The Pearson correlation validity between VO2-max and VO2-maxnormal

is indicated in Table 11. The correlation value of rxy= 0.673 is also considered to be of

moderately-high strength. The positive sign indicates the direct relationship between the data

of the two variables.

TABLE 11. Concurrent validity between VO2-max and VO2-maxnormal.

Correlations

VO-2 max

(ml/kg/min)

VO-2 maxnorm

(ml/kg/min)

VO-2 max (ml/kg/min) Pearson Correlation 1 .673**

Sig. (2-tailed) .000

N 23 23

VO-2 max (norm) (ml/kg/min) Pearson Correlation .673** 1

Sig. (2-tailed) .000

N 23 25

**. Correlation is significant at the 0.01 level (2-tailed).

Reliability analysis. The RHR and VO2-max reliabilities were determined by an internal

consistency test. This was done by splitting the original data set into even and odd cases before a

reliability analysis was performed on the corresponding even and odd variables. RHR and VO2-

max reliabilities were found to be of moderate strength at rxx= 0.530 and rxx= 0.401,

respectively. Tables 12 and 13 indicate the reliability statistics for RHR and VO2-max,

respectively.

21RHR and VO2-max

TABLE 12. RHR reliability is moderate strength.

Reliability Statistics

Cronbach's

Alpha N of Items

.530 2

TABLE 13. VO2-max reliability is moderate strength.

Reliability Statistics

Cronbach's

Alpha N of Items

.401 2

The standard error of measurement (SEM) was computed via a scientific calculator using

the following formula:

SEM=SD √1−¿r xx¿

Where SD = average SD between the even and odd cases and rxx = reliability coefficient. The

SD for each RHR data set is shown in Table 14. The average SDRHR = 7.701 and the rxx = 0.530.

Thus, SEMRHR = 5.280, or the range for any particular RHR is ± 5.28 bpm.

TABLE 14. SD of even and odd cases for RHR.

22RHR and VO2-max

Descriptive Statistics

N Std. Deviation

RHReven (bpm) 12 6.941

RHRodd (bpm) 13 8.460

Valid N (listwise) 12

The SD for each VO2-max data set is shown in Table 15. The average SDVO2-max = 6.205

and the rxx = 0.401. Thus, SEMVO2-max = 4.802, or the range for any particular VO2-max is ±

4.802 ml*kg-1min-1.

TABLE 15. SD of even and odd cases for VO2-max.

Descriptive Statistics

N Std. Deviation

VO-2 maxeven (ml/kg/min) 12 5.73026

VO-2 maxodd (ml/kg/min) 13 6.67875

Valid N (listwise) 12

Data profiling. Excel was used to calculate z-scores of the VO2-max raw data values

with respect to the group utilizing the following formula:

z= x−medianSD

where x = raw data value, median = 37.53, and SD = 4.730 for the VO2-max data (Table 6).

Figure 9 shows the individual VO2-max profile with respect to the group as the reference

standard. The figure shows three participants (1, 5 and 10) were scored as zero.

23RHR and VO2-max

INDIVIDUALS COMPARED TO OWN GROUP

z score

Subject VO2- max relative to own group

FIGURE 9---Individual VO2-max standardized scores compared to the group.

Excel was used to calculate z-scores of the VO2-max raw data values with respect to the

norm-reference group utilizing the following formula:

z= x−median(std)SD (std)

where x = raw data value for the VO2-max data set with median (std) = 34.60 and

SD (std) = 5.019 for the VO2-maxnorm data (Table 6). Figure 10 shows the individual VO2-max

profile with respect to the norm-reference group. The figure shows that 17 subjects scored

above the criterion, five subjects scored below the criterion, and three participants were scored as

1 3 5 7 9 11 13 15 17 19 21 23 25

-3

-2

-1

0

1

2

3

individual VO-2 max profile

each subject

24RHR and VO2-max

zero (1, 5 and 13). Thus, more individuals scored better compared to the norm-reference group

than to the sample group.

INDIVIDUALS COMPARED TO NORM-REFERENCE GROUP

z score

Subject VO2- max relative to NR group

FIGURE 10---Individual VO2-max standardized scores compared to the NR group.

Finally, a scientific calculator was used to compute the z-score of the group VO2-max

median with respect to the norm-reference group utilizing the following formula:

z=median(grp)−median(std)SD(std)

=0.584

where median (grp) = 37.53 for the VO2-max data set with median (std) = 34.6 and

1 3 5 7 9 11 13 15 17 19 21 23 25

-3

-2

-1

0

1

2

3

individual VO-2 max profile

each subject

25RHR and VO2-max

SD (std) = 5.019 for the VO2-maxnorm data (Table 6).

Figure 11 shows the group VO2-max profile with respect to the norm-reference group.

The figure shows that the group scored better overall compared to the norm-reference group.

GROUP COMPARED TO NORM-REFERENCE GROUP

z score

Group VO2-max relative to NR group

FIGURE 11---Group VO2-max standardized scores compared to the norm-reference group.

CONCLUSIONS

This study has shown that there is an inverse relationship between RHR and VO2-max.

These two inversely-related variables were found to have moderately-high correlation strength.

This may be attributed to the physiological mechanism that a lower RHR is indicative of a heart

which works more efficiently in delivering oxygen (increased VO2-max) throughout the body.

10

0.25

0.5

group VO-2 max profile

group

1

-3

-2

-1

0

1

2

3

group VO-2 max profile

group

26RHR and VO2-max

This does not necessarily mean that RHR affects VO2-max—only that there exists a strong

inverse correlation between them. Even though effect size = 0.60, it is important to note the

moderately-high correlation strength is dependent on the relatively small sample size (N=25)

within a particular community. The small sample size and the volunteer effect may limit the

external validity of this study. The participants may not be generalizable to the overall

population (e.g. fit people may be more apt to volunteer). However, because of the moderately-

high correlation validity of this data group with respect to the norm-reference group in the

ACLS, the results of this study should serve to encourage further research involving a much

larger sample size. Any compromise of internal validity of the study was minimized since

researcher influence was very limited. The study is characterized by research reliability as the

design and methodology of data collection is sound and replicable.

A relatively higher VO2-max and lower RHR is desirable since this is a measure of good

cardiovascular health and increased exercise endurance. According to a review by Carter,

Banister and Blaber (2003), endurance exercise tends to lower RHR due to an autonomic

adaptive response in heart rate. In addition, research has shown that interval training can boost

VO2-max capacity (Rozenek et al., 2007). The results of this study have practical applications.

Can the average person, who lacks the inherent trait of high oxygen capacity which characterizes

many athletes, lower his or her RHR and possibly increase VO2-max capacity by performing

regular exercise?

Intrinsic variables (e.g. gender, age, bodyweight, body composition, heart and lung size,

and having a disease such as heart disease) as well as extrinsic variables (e.g. medications and

exercise) may influence RHR as well as VO2-max capacity. Notably, this study has shown

gender to be the strongest correlating variable with respect to VO2-max capacity and RHR. This

27RHR and VO2-max

is consistent with the research findings previously cited in the introduction. The research has

shown that females generally have a lower VO2-max capacity and a higher RHR than males.

Age and bodyweight were found to be weaker correlating variables with respect to VO2-max

capacity and RHR. Further longitudinal research studies examining how RHR may affect VO2-

max capacity and how the latter can be increased as a result of exercise is necessary.

REFERENCES

ACSM’s Guidelines for Exercise Testing and Prescription (7th ed.). (2006). Baltimore, MD:

American College of Sports Medicine.

Amara, C.E., Koval, J.J., Johnson, P.J., Paterson, D.H., Winter, E.M., & Cunningham, D.A.

(Nov 2000). Modeling the influence of fat-free mass and physical activity on the decline

in maximal oxygen uptake with age in older humans. Experimental Physiology, 85(6),

877-886.

Carter, J.B., Banister, E.W. & Blaber, A.P. (2003). Effect of endurance exercise on autonomic

control of heart rate. Sports Medicine, 33(1), 33-46. Retrieved April 20, 2009, from

SPORTDiscus database.

Dasqupta, P.K., Mukhopadhyay, A.K. & De, A.K. (Apr 2000). A study of cardio-pulmonary

efficiency in different categories of runners. Indian Journal Physiological

Pharmocology, 44(2), 220-4. Retrieved April 23, 2009, from PubMed database.

Harms, C.A. (Oct 2005). Does gender affect pulmonary function and exercise capacity?

Respiratory Physiology & Neurobiology, 151(2), 124-131.

Olfert, I.M., Balouch, J., Kleinsasser, A., Knapp, A., Wagner, H., Wagner, P., et al. (Feb 2004).

Does gender affect human pulmonary gas exchange during exercise? Journal of

28RHR and VO2-max

Physiology, 557, 529-541.

Rozenek, R., Funato, K., Kubo, J., Hoshikawa, M., & Matsuo, A. (Feb 2007). Physiological

responses to interval training sessions at velocities associated with VO2max. Journal of

Strength and Conditioning Research, 21(1), 188-192.

Shephard, R.J. (Apr 2008). Maximal oxygen intake and independence in old age. British

Journal of Sports Medicine, doi: 10.1136/bjsm.2007.044800. Retrieved April 14, 2009,

from SPORTDiscus database.

29RHR and VO2-max

TABLES & FIGURES

TABLE 16. Frequency distribution of age.

age (yrs)

Frequency Percent Valid Percent

Cumulative

Percent

Valid 23 1 4.0 4.0 4.0

25 1 4.0 4.0 8.0

26 1 4.0 4.0 12.0

29 2 8.0 8.0 20.0

30 1 4.0 4.0 24.0

32 1 4.0 4.0 28.0

34 1 4.0 4.0 32.0

36 1 4.0 4.0 36.0

41 1 4.0 4.0 40.0

43 3 12.0 12.0 52.0

46 1 4.0 4.0 56.0

47 1 4.0 4.0 60.0

54 1 4.0 4.0 64.0

56 1 4.0 4.0 68.0

57 1 4.0 4.0 72.0

58 2 8.0 8.0 80.0

62 2 8.0 8.0 88.0

30RHR and VO2-max

66 1 4.0 4.0 92.0

79 1 4.0 4.0 96.0

83 1 4.0 4.0 100.0

Total 25 100.0 100.0

TABLE 17. Frequency distribution of bodyweight.

bodyweight (lbs)

Frequency Percent Valid Percent

Cumulative

Percent

Valid 125 1 4.0 4.0 4.0

130 1 4.0 4.0 8.0

135 1 4.0 4.0 12.0

139 1 4.0 4.0 16.0

141 1 4.0 4.0 20.0

153 1 4.0 4.0 24.0

155 1 4.0 4.0 28.0

156 1 4.0 4.0 32.0

158 1 4.0 4.0 36.0

166 1 4.0 4.0 40.0

175 1 4.0 4.0 44.0

178 1 4.0 4.0 48.0

184 1 4.0 4.0 52.0

185 1 4.0 4.0 56.0

187 2 8.0 8.0 64.0

193 1 4.0 4.0 68.0

194 1 4.0 4.0 72.0

31RHR and VO2-max

195 1 4.0 4.0 76.0

198 1 4.0 4.0 80.0

205 1 4.0 4.0 84.0

208 1 4.0 4.0 88.0

214 1 4.0 4.0 92.0

215 1 4.0 4.0 96.0

238 1 4.0 4.0 100.0

Total 25 100.0 100.0

TABLE 18. Frequency distribution of RHR.

RHR (bpm)

Frequency Percent Valid Percent

Cumulative

Percent

Valid 53 1 4.0 4.0 4.0

54 1 4.0 4.0 8.0

56 1 4.0 4.0 12.0

58 2 8.0 8.0 20.0

61 1 4.0 4.0 24.0

63 1 4.0 4.0 28.0

64 1 4.0 4.0 32.0

65 1 4.0 4.0 36.0

66 2 8.0 8.0 44.0

67 3 12.0 12.0 56.0

68 2 8.0 8.0 64.0

69 2 8.0 8.0 72.0

72 1 4.0 4.0 76.0

73 1 4.0 4.0 80.0

74 2 8.0 8.0 88.0

76 1 4.0 4.0 92.0

80 1 4.0 4.0 96.0

32RHR and VO2-max

83 1 4.0 4.0 100.0

Total 25 100.0 100.0

TABLE 19. Frequency distribution of VO2-max.

VO-2 max (ml/kg/min)

Frequency Percent Valid Percent

Cumulative

Percent

Valid 20.40 1 4.0 4.0 4.0

24.59 1 4.0 4.0 8.0

27.48 1 4.0 4.0 12.0

28.56 1 4.0 4.0 16.0

31.34 1 4.0 4.0 20.0

32.42 1 4.0 4.0 24.0

33.59 1 4.0 4.0 28.0

34.47 1 4.0 4.0 32.0

35.67 1 4.0 4.0 36.0

35.92 1 4.0 4.0 40.0

36.35 1 4.0 4.0 44.0

36.57 1 4.0 4.0 48.0

37.40 1 4.0 4.0 52.0

37.53 1 4.0 4.0 56.0

38.03 1 4.0 4.0 60.0

38.23 1 4.0 4.0 64.0

33RHR and VO2-max

38.60 1 4.0 4.0 68.0

39.55 1 4.0 4.0 72.0

39.56 1 4.0 4.0 76.0

39.75 1 4.0 4.0 80.0

39.90 1 4.0 4.0 84.0

41.20 1 4.0 4.0 88.0

42.67 1 4.0 4.0 92.0

44.78 1 4.0 4.0 96.0

47.61 1 4.0 4.0 100.0

Total 25 100.0 100.0

TABLE 20. Frequency distribution of VO2-maxnormal.

VO-2 max (norm) (ml/kg/min)

Frequency Percent Valid Percent

Cumulative

Percent

Valid 26.70 1 4.0 4.0 4.0

29.90 3 12.0 12.0 16.0

33.00 3 12.0 12.0 28.0

34.60 6 24.0 24.0 52.0

37.80 4 16.0 16.0 68.0

41.00 3 12.0 12.0 80.0

42.60 2 8.0 8.0 88.0

44.20 3 12.0 12.0 100.0

Total 25 100.0 100.0

TABLE 21. Correlation between age and VO2-max.

34RHR and VO2-max

Correlations

age (yrs)

VO-2 max

(ml/kg/min)

age (yrs) Pearson Correlation 1 -.387

Sig. (2-tailed) .068

N 25 23

VO-2 max (ml/kg/min) Pearson Correlation -.387 1

Sig. (2-tailed) .068

N 23 23

FIGURE 12—Scatterplot of age as a function of VO2-max. This plot indicates that VO2-max

decreases slightly with increasing age.

. TABLE 22. Correlation between bodyweight and VO2-max.

35RHR and VO2-max

Correlations

bodyweight (lbs)

VO-2 max

(ml/kg/min)

bodyweight (lbs) Pearson Correlation 1 .120

Sig. (2-tailed) .587

N 25 23

VO-2 max (ml/kg/min) Pearson Correlation .120 1

Sig. (2-tailed) .587

N 23 23

FIGURE 13—Scatterplot of bodyweight as a function of VO2-max. This plot indicates that

VO2-max only slightly increases with bodyweight.