Laboratory exercise testing: Exercise testing W170 and maximal tests

Laboratory exercise testing:

Exercise testing

W170and

maximal tests

W170Exercise test estimating theoretical physical

working capacity at hear rate of 170 beets/min.

Physiological principle:

A linear relation (positive correlation) between HR and intensity of exercise (load) in a range from 120 to 170 (180) beets/min.

Note: There is no change in systolic volume from 120–170 (180) beets/min and therefore cardiac output depends only on heart rate. Systolic volume rises till 120 beets/min, from 170–180 beets/min slightly decreases (short diastole).

The test is looking for a theoretical load (P) [W] which should be produced by tested person at his (her) HR

170 beets/min.

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W170Next characteristics:

1) It is one of the oldest sub-maximal tests evaluating fitness level, an effect of a training or impact of a rehabilitation intervention….

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2) There was a hypothesis of strong correlation of the test with an aerobic power (VO2max). However, current findings show, that the test is valid only for common population (mainly for men). It is not suitable for athletes.

3) HR 170 beets/min is approximately the value when is a healthy young man reaching his anaerobic threshold. For the elderly or ill (who has reduced HRmax and HR at AnT) is sometimes used modification of the test W150 či W130.

W170

Protocol:

1) 2(sometimes 3–4) stages. There can be 1 min long optional pause between stages.

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Equipment: - cycle ergometer- HR monitor

2) duration of each stage 4–6 min (reaching of steady state)

3) measurement of HR at the end of each stage (during last 15 s)

4) load [W] should increase HR:- at the end of the 1. stage: 120–140 bpm- at the end of the 2. stage: 140–160 bpm

W170

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Determination of the load [W] per kg of weight:

♂ ♀ and children

trained

1. stage 1,5 W/kg 1 W/kg ≥ 2 W/kg

2. stage 2 W/kg 1,5 W/kg ≥ 2,5 W/kg

Final power depends on pedal rate as well. The pedal rate should be kept in the range ±5 revolution/min.

Optimal pedal rate for sedentary is 60 rev/min (55–65), for trained higher (even 85–95). The higher is load, the higher should be pedal rate.

W170

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Protocol (♀ 60 kg):

1. stage

[min]

[W]

5 min

2. stage

5 min

60 W

90 WHR 1

125 bpmHR 2

145 bpm

Result of the test: 1) 60 W = 125 bpm 2) 90 W = 145 bpm 3) x W = 170 bpm

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Calculation of W170 (extrapolation)

×

×

140 *

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Calculation of W170 (extrapolation)

×

×

140

Result of the test: 1) 60 W = 125 bpm 2) 90 W = 145 bpm 3) 140 W = 170 bpm

Index W170: 140 W : weight (60) = 2,33 W/kg

W170

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Population norms:

(Heller, 2005)

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Comparison of a untrained (N) and a trained (T) with use of three stages

W170

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To create a line, two points are enough. It means to realize W170, two exercise stages should be enough too. There are some authors who recommend at least three stages. More stages reduce the risk of error.

××

×

W170

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If the HR at the end of the first stage is lower than 120 bpm, there may be a risk of major error. The reason is linearity from 120 to

170…..In this case it is useful to add the third stage.

Note:

W170

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W170 test can be use for indirect determination o aerobic power:

W170 test can be use for evaluation of working capacity at higher HR as well. However, by reason of above mentioned problems of linear relation… there is at HR higher than 170-180 bpm increase in error

of the evaluation.

1) Realization of standard test and determination of load at HRmax which can be calculated from formula 220-age

2) Determined load is used in formula (Bunc, 1989): VO2max (ml/min) = 10.88 × [W] + 411

- This formula can be used for load from 100 to 400 W, with considered error 10%.

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Indirect determination of VO2max for ♀ 60 kg, 20 year

×

×

140

W at HRmax?1) 220-20= 200 bpm2) 190 W = 200 bpm

VO2max = 10.88 × [W] + 411VO2max = 10.88 × 190 + 411VO2max = 2478 ml/min

190

VO2max = 41,3 ml/kg/min

2478 : weight (60 kg)

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Maximal exercise testLaboratory tests when the load is gradually

increasing till maximum.

Sometimes is called spiroergometri.

A working capacity is a load reached immediately before appearance of the signals of ischemia on EKG record, which are the reasons to stop the test. A working tolerance is

the highest load at the maximum, when the criteria for termination of the test were reached.

The main aim is to measure maximum oxygen consumption (aerobic power) - VO2max(peak). It

means to evaluate efficiency of cardiovascular system and estimate working capacity or working tolerance.

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Maximal exercise testThe sources of the load:

- cycle ergometer- treadmill- arm ergometer

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Next equipment:- HR monitors- unit for pulmonary gas exchange (PGE) measurement

- analyzers for measurement of O2 a CO2 in inspired and expired air (importance of calibration one time per day- mixture of gases: e.g. CO2 – 5 %, O2 – 15 %, rest N2)- flow sensor measuring volume of inspired and expired air (importance of calibration before every measurement)

Every devises are controlled from one PC = spiroergometrics unit

PC

Calibration pump

Spiroergometrics unit

Unit for PGE measurementEKG

Suction pump for EKG

Mixture of calibration gases

HR receiver

Suction electrodes EKG

Unite for pulmonary gas exchange measurement

Measurement of O2 consumption and CO2 production

- from difference in concentration in inspired and expired air

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Tested person wears mask or mouthpiece with clamp

Mouthpiece – discomfort, but lower death space

Maska – comfortable (breathing via nose), but bigger death space (accumulation of CO2) + leaking.

Measurement of ventilation

- calculation from breathing frequency and tidal volume

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Air sampling for CO2 a O2 analysis

Information about volume of inspired and

expired air

Mast fit.

Flow sensor working on principle different pressure in the front of and behind of membrane.

Disinfection and calibration prior to each measurement.

Maximal exercise testIncrease in the load:

- continual (ramp) test

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[min]

[W][W/kg]

There is steples increase in the load [W] till maxima.

Problem: delay in O2 consumption VO2 does not correspond with the load.

O2


- gradual (step) test

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[min]

[W][W/kg] There is gradual increase in

load [W] with use of steps from low values to maxima:

O2 consumption corresponds to the load at the end of each step (reaching steady state)

0,5; 1; 2–5 min.


Every minute (step) increase about o 1/3 W/kg of waight. VO2 should not increase between steps more than 3 METs.

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- ♂ 75 kg = 25 W/min- ♀ 60 kg = 20 W/min

Total duration of the test should be from 8–12 min.

If the test is shorter or longer, VO2max values are lower.

Generally – for sedentary, obese and elderly, tests should e longer with lower increase in load)

Maximal exercise testIncrease in the load :

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Sedentary male:

Wmax = 175 (around). If increase about 25W/min, duration will be 7 minutes.

Trained cyclist

Wmax = 550 (or more). If increase about 25W/min, duration will be 22 minutes.

Solution: higher increase (30 W) + change in exercise protocol:

1) 4–5 min warming-up at constant low intensity 2) test starts at the load corresponding with load at individual

anaerobic threshold

Maximal exercise test

Sedentary: 7 steps x 25 W = 175 W

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175 W


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Trained would need by 22 steps x 25 W = 550 W

550 W

Problem: 1) Long duration

2) Low (boring) intensity at the beginningACCORDINGLY


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Trained would need by 22 steps x 25 W = 550 W

550 W

Problem: 1) Long duration

2) Low (boring) intensity at the beginningACCORDINGLY

W at AnT

4–5 min

Test:3–8 min

Minute long brake, not necessary


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How to estimate AnT?

550 W

1) Based on population norms...

2) By using W70 test, which could serve as a warming-up at the same time

W at AnT

4–5 min

test:3–8 min

THAN


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How to estimate AnT?

550 W

Using W170 test as a warming-up before test to maximum

W 170

1. step

Test:3–8 min

2. step

Maximal exercise testChosen monitored parameters:

1) Heart rate (HRmax, HR at AnT) and saturation

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A saturation means percentage of saturation of blood bye O2 from maximum possible amount. It is at the rest about 98% and decreases during exercise. It can be lower than 90% at maximum exercise.

Saturation HR

Digital pulse oxymetere



2) Power – P (Wmax, W at AnT)

P = F × v

*[W = Nm/s]

forcespeed

Work = force acting upon a distance

power = work for time

= [N × m] = [J]

= [Nm/s] = [W]

Or…




The values of Wmax/kg:

♂ ♀ trained KVS illnesses

3,5 2,8 ≥6–9 od 0,5

See next table:

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Chosen monitored parameters:



3) Lactate – for estimation of so called metabolic AnT

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(Placheta et al, 2001) *

Invasive estimation of AnT from level of a blood lactate


Chosen monitored parameters:



3) Lactate – for estimation of so called metabolic AnT

4) Gas exchange (O2 a CO2) and ventilation

RQ =CO2

O2

RQ of fats = 0,7. RQ of carbohydrates = 1

However during maximal exercise test RQ overlap level of 1. The reason is reduction of acidity with help of bicarbonates:

HH+++ HCO+ HCO--3 3 → H→ H22COCO3 3 → H→ H22O + COO + CO22

*Note: HH22COCO3 3 - carbonic acid - carbonic acid

Maximal exercise testHowever during maximal exercise test RQ overlap level of 1. The reason is

reduction of acidity with help of bicarbonates:

HH+++ HCO+ HCO--3 3 → H→ H22COCO3 3 → H→ H22O + COO + CO22

[W]

[l]O2

CO2

Deflection point from linear trend between CO2 output and exercise intensity.

AnP*

Maximal exercise testThis deflection point represent anaerobic threshold, which is called as a respiration or ventilation AnT.

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Similar increase (deflection point) can be seen on the curve of ventilation - because increase of pCO2 in blood stimulates ventilation (due to chemoreceptors).

[W]

[l]

V

Ventilation AnT

So called „talking“ test can be used for estimation.

Determination of ventilation AnT (Tvent)

*(Heller, 2005)

V-slope method for determination of AnT

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Linear relation is disturbed for the benefit of CO2 output.

O2 consumption during maximal test

*(Heller, 2005)

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Plateau in O2 consumption:

1) It is situation when VO2max is reached and next increase in exercise intensity does not cause father increase of it.

2) It is possible to sustain for seconds (trained longer).

3) It is evident among less then 50% tested. The most of the tested finish early from reason of uncomfortable filings.

4) It is one criteria for reaching maximum exercise intensity.

O2 consumption during maximal test

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Maximal exercise test is ended when the tested feels inability to continue - reaching volitional maximum

Maximum = at lest 18.

(Borg, 1982)

Criteria of reaching maximum

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1) Plateau in VO2.

2) RQ higher than 1.

3) Lactate is 1,5 min after cessation of exercise >8mmol/l

4) HRmax >85 % from predicted maximum

VO2max x VO2peak.

Maximum test on treadmill

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The example of the set used in our laboratory:

than increase every 30 s 4 min

Tr. ♂

1 min

80

km/hour%

85

105

115

125

135

145

155

157 Than increase

in inclination about 2 %Tr. ♀ 7

0km/hour

%75

85

95

105

115

127

129

1211

Receiver of HR.

Safety belt.

Maximum test on treadmill

Example of next protocols:

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Some parameters during maximal test

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VCO2 – volume of expired CO2, RER – respiration quotient, V – ventilation, FIO2–FEO2 – utilization of O2 from ventilated air

Some parameters during maximal test

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VE – ventilationVCO2 – volume of expired CO2 VO2 – volume of inspired O2 PETO2 – partial pressure of O2 at the end of expirationPETCO2 – partial pressure of CO2 the end of expirationLA – level of lactateHCO3

- – bicarbonateR – respiration quotientpH – pHW – load

Results of maximal exercise test



VO2l/min


Measurement of VO2 in the field conditions

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A B

Determination of VO2max from regression equation (Jurča el al.)

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1. Evaluation of physical activity

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2. Filing of different parameters

Determination of VO2max from regression eguetion (Jurča el al.)

Výpočet VO2max dle regresní rovnice (Jurča el al.)

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3. Final evaluation of results

Literature:

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Heller, J. (2005). Laboratory Manual forHuman and Exercise Physiology. Charales Univeristy in Prague: The Karolinum Press.

Maud, C. Foster (Eds.). Psychological assessment of human fitness. Champaign, IL: Human Kinetics.

Placheta, Z., Siegelová, J., Štejfa, M., Jančík, J., Homolka, P., & Dobšák, P. (2001). Zátěžové vyšetření a pohybová léčba ve vnitřním lékařství. Brno: Masarykova Univerzita.

Silbernagl, S., & Despopoulos, A. (1988/1993). Atlas fyziologie člověka (E. Trávničková et al., Trans.). Praha: Grada.

Documents

Laboratory exercise testing: Exercise testing W170 and maximal tests