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Laboratory exercise testing: Exercise testing W170 and maximal tests
W170 Exercise 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. *
W170 Next 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…. * 2) There was a hypothesis of strong correlation of the test with an aerobic power (VO 2 max). 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. * 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 * Determination of the load [W] per kg of weight: and children trained 1. stage 1,5 W/kg1 W/kg 2 W/kg 2. stage 2 W/kg1,5 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 * Protocol ( 60 kg): 1. stage [min] [W] 5 min 2. stage 5 min 60 W 90 W HR bpm HR bpm Result of the test: 1) 60 W = 125 bpm 2) 90 W = 145 bpm 3) x W = 170 bpm
* Calculation of W170 (extrapolation) × × 140 *
* 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 * Population norms: (Heller, 2005)
* Comparison of a untrained (N) and a trained (T) with use of three stages
W170 * 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 * 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 * 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 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): VO 2 max (ml/min) = × [W] This formula can be used for load from 100 to 400 W, with considered error 10%.
* Indirect determination of VO 2 max for 60 kg, 20 year × × 140 W at HRmax? 1)220-20= 200 bpm 2)190 W = 200 bpm VO 2 max = × [W] VO 2 max = × VO 2 max = 2478 ml/min 190 VO 2 max = 41,3 ml/kg/min 2478 : weight (60 kg) *
Maximal exercise test Laboratory 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) - VO 2 max(peak). It means to evaluate efficiency of cardiovascular system and estimate working capacity or working tolerance. *
Maximal exercise test The sources of the load: - cycle ergometer - treadmill - arm ergometer * Next equipment: - HR monitors - unit for pulmonary gas exchange (PGE) measurement - analyzers for measurement of O 2 a CO 2 in inspired and expired air (importance of calibration one time per day- mixture of gases: e.g. CO 2 – 5 %, O 2 – 15 %, rest N 2 ) - 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 measurement EKG Suction pump for EKG Mixture of calibration gases HR receiver Suction electrodes EKG
Unite for pulmonary gas exchange measurement Measurement of O 2 consumption and CO 2 production - from difference in concentration in inspired and expired air * 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 CO 2 ) + leaking. Measurement of ventilation - calculation from breathing frequency and tidal volume
Air sampling for CO 2 a O 2 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 test Increase in the load: - continual (ramp) test * [min] [W] [W/kg] There is steples increase in the load [W] till maxima. Problem: delay in O 2 consumption VO 2 does not correspond with the load. O2O2
Maximal exercise test Increase in the load: - gradual (step) test * [min] [W] [W/kg] There is gradual increase in load [W] with use of steps from low values to maxima: O 2 consumption corresponds to the load at the end of each step (reaching steady state) 0,5; 1; 2–5 min.
Maximal exercise test Increase in the load: Every minute (step) increase about o 1/3 W/kg of waight. VO 2 should not increase between steps more than 3 METs. * - 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, VO 2 max values are lower. Generally – for sedentary, obese and elderly, tests should e longer with lower increase in load)
Maximal exercise test Increase in the load : * 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 * 175 W
Maximal exercise test * Trained would need by 22 steps x 25 W = 550 W 550 W Problem:1) Long duration 2) Low (boring) intensity at the beginning ACCORDINGLY
Maximal exercise test * Trained would need by 22 steps x 25 W = 550 W 550 W Problem:1) Long duration 2) Low (boring) intensity at the beginning ACCORDINGLY W at AnT 4–5 min Test: 3–8 min Minute long brake, not necessary
Maximal exercise test * 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
Maximal exercise test * How to estimate AnT? 550 W Using W170 test as a warming-up before test to maximum W step Test: 3–8 min 2. step
Maximal exercise test Chosen monitored parameters: 1) Heart rate (HRmax, HR at AnT) and saturation * A saturation means percentage of saturation of blood bye O 2 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
Maximal exercise test Chosen monitored parameters: 1) Heart rate (HRmax, HR at AnT) and saturation 2) Power – P (Wmax, W at AnT) P = F × v * [W = Nm/s] force speed Work = force acting upon a distance power = work for time = [N × m] = [J] = [Nm/s] = [W] Or…
Maximal exercise test Chosen monitored parameters: 1) Heart rate (HRmax, HR at AnT) and saturation 2) Power – P (Wmax, W at AnT) The values of Wmax/kg: trainedKVS illnesses 3,52,86–9 od 0,5 See next table: *
Maximal exercise test Chosen monitored parameters: 1) Heart rate (HRmax, HR at AnT) and saturation 2) Power – P (Wmax, W at AnT) 3) Lactate – for estimation of so called metabolic AnT *
(Placheta et al, 2001) * Invasive estimation of AnT from level of a blood lactate
Maximal exercise test Chosen monitored parameters: 1) Heart rate (HRmax, HR at AnT) and saturation 2) Power – P (Wmax, W at AnT) 3) Lactate – for estimation of so called metabolic AnT 4) Gas exchange (O 2 a CO 2 ) and ventilation RQ = CO 2 O2O2 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: H + + HCO - 3 H 2 CO 3 H 2 O + CO 2 * H 2 CO 3 - carbonic acid Note: H 2 CO 3 - carbonic acid
Maximal exercise test However during maximal exercise test RQ overlap level of 1. The reason is reduction of acidity with help of bicarbonates: H + + HCO - 3 H 2 CO 3 H 2 O + CO 2 [W] [l] O2O2 CO 2 Deflection point from linear trend between CO2 output and exercise intensity. AnP *
Maximal exercise test This deflection point represent anaerobic threshold, which is called as a respiration or ventilation AnT. * Similar increase (deflection point) can be seen on the curve of ventilation - because increase of pCO 2 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 * Linear relation is disturbed for the benefit of CO 2 output.
O 2 consumption during maximal test * (Heller, 2005)
* Plateau in O 2 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. O 2 consumption during maximal test
* 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 * 1) Plateau in VO 2. 2) RQ higher than 1. 3) Lactate is 1,5 min after cessation of exercise >8mmol/l 4) HRmax >85 % from predicted maximum VO 2 max x VO 2 peak.
Maximum test on treadmill * The example of the set used in our laboratory: than increase every 30 s 4 min Tr. 1 min 8080 km/hour % Than increase in inclination about 2 % Tr km/hour %
Receiver of HR. Safety belt.
Maximum test on treadmill Example of next protocols: *
Some parameters during maximal test * VCO 2 – volume of expired CO 2, RER – respiration quotient, V – ventilation, FIO 2 –FEO 2 – utilization of O 2 from ventilated air
Some parameters during maximal test * V E – ventilation VCO 2 – volume of expired CO 2 VO 2 – volume of inspired O 2 P ETO2 – partial pressure of O 2 at the end of expiration P ETCO2 – partial pressure of CO 2 the end of expiration LA – level of lactate HCO 3 - – bicarbonate R – respiration quotient pH– pH W – load
Results of maximal exercise test
VO2l/min Results of maximal exercise test
Measurement of VO 2 in the field conditions * A B
Determination of VO 2 max from regression equation (Jurča el al.) * 1. Evaluation of physical activity
* 2. Filing of different parameters Determination of VO 2 max from regression eguetion (Jurča el al.)
Výpočet VO 2 max dle regresní rovnice (Jurča el al.) * 3. Final evaluation of results
Literature: * 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.