4 Assessing Cardiorespiratory Fitness chapter 4 chapter Author name here for Edited books

Cardiorespiratory Endurance Ability to perform dynamic exercise involving large muscle groups at moderate-to-high intensity for prolonged periods (ACSM 2000) Criterion measure is VO2max VO2max is the most valid measure of the cardiorespiratory system’s functional capacity. VO2max reflects maximal ability of cardiorespiratory system to deliver O2 and nutrients to muscles and ability of muscles to use them. . (continued)

. Absolute VO2 A discrete volume of O2 consumption in reference to time Expressed in L/min or ml/min Used for nonweight-bearing modalities Directly related to body weight

Synonyms of Cardiorespiratory Fitness Maximal Aerobic Capacity Functional Capacity Physical Work Capacity Maximal Oxygen Uptake or Consumption VO2max or VO2peak Cardiovascular, Cardiorespiratory, or Cardiopulmonary Endurance, Fitness or Capacity

. Relative VO2 A volume of O2 consumption relative to unit of body mass and time Expressed as ml/kg/min Used for weight-bearing modalities Best for comparing people of different body size Can express as ml/kgFFM/min to look at O2 consumption of muscle mass

. Gross Versus Net VO2 . . Not synonymous terms Gross VO2 = caloric cost of exercise and rest (Gross = exercise + rest) Net VO2 = caloric cost of exercise only (Net = Gross – rest) Express in either absolute or relative terms Rest is 3.5 ml/kg/min or 1 MET . .

Cardiorespiratory fitness is considered health-related because: Low levels of CRF have been associated with markedly increased risk of premature death from all causes, specifically CVD Increases in CRF are associated with a reduction in death of all causes High levels of CRF are associated with higher levels of habitual physical activity, which in turn are associated with many health benefits

Factors to decide which CRF test: Time demands Expense or cost Personnel needed (i.e. qualifications) Equipment and facilities needed Physician supervision needed Population tested (i.e. safety concerns) Need for accuracy of data

CRF Pre-Test Considerations: Abstain from eating (> 4 hours) Abstain from strenuous exercise (24 hours) Abstain from caffeine (12-24 hours) Abstain from nicotine (> 3 hours) Abstain from alcohol (>24 hours) Medication considerations (if client’s meds affect resting or exercise HR, it will invalidate the test.

Graded Exercise Testing Objective assessment of functional capacity Can use maximal or submaximal tests Can observe and compare numerous variables from baseline testing to follow-up testing Instrumental for exercise programming and goal setting (continued)

Graded Exercise Testing (continued) ACSM recommends maximal exercise testing prior to start of vigorous exercise program for older, moderate-risk, or high-risk individuals. Vigorous is >60% VO2max, or >6 METs. . (continued)

Graded Exercise Testing (continued) ACSM recommends submaximal testing for low- or moderate-risk individuals prior to starting a moderate-intensity exercise program Moderate intensity is 40% to 60% VO2max, or 3 to 6 METs. .

GXT Guidelines Review contraindications to exercise testing. Use maximal or submaximal GXT as appropriate. If goal is diagnosing CAD, use max GXT. Little difference exists in danger levels (max v. submax). Use multiple stages (hence “graded”). For non-ramp protocols, stages usually last 2 to 3 minutes each. Know GXT termination criteria.

. . VO2 peak Versus VO2 max . Peak criteria are similar to criteria for VO2 max except RER is <1.15 and no plateau is attained. Children, older adults, sedentary people, and those with known disease are likely to attain VO2 peak, but not max. .

Procedures for Conducting GXTs Pretest instructions Paperwork Resting baseline data (HR, BP, EKG) Instructions and warm-up stage Periodic (and continual) monitoring Stage changes (depend on protocol) Termination (criteria depend on protocol, client, S/S) Cool-down (recovery)

Rating of Perceived Exertion (RPE) Original 6 to 20 scale was revised to 0 to 10 scale. Both highly related to HR and VO2 Subjective scales of overall exertion Moderate intensity is 12 to 14 on original scale and 6 on revised scale. OMNI pictorial scales may also be used for children through adult age groups. .

Maximal Exertion Protocols Choose protocol and modality wisely! Individualized protocol is best Highest VO2 is with uphill running; lowest is with arm ergometry Usually lasts 8 to 12 minutes long Can be a continuous or discontinuous protocol Discontinuous protocols take longer .

Submaximal Exertion Protocols Choose protocol and modality wisely! Similar to maximal exertion GXTs May or may not involve stage change(s) Monitor constantly for S/S and proper hemodynamic response Generally terminated based on predetermined criteria (e.g.,: 85% age-predicted maximal HR) Results can be used to estimate exercise tolerance

Treadmill Protocols Manipulate workload via speed (mph) and grade (%). ACSM’s TM walking and running equations estimate metabolic cost of exercise (energy expenditure). Assume steady state stages (overestimates if not) Cannot account for anaerobic component Walking equation better if walking with incline Use running equation for speeds >5mph or slow jog (3mph) (continued)

Treadmill Protocols (continued) Many treadmill protocols exist. Choose best one for your client. Many have their own equation to calculate VO2. Some use nomograms. .

. Calculating VO2 . . . . . . 70 kg woman walks at 3.5 mph at no grade VO2 = Horizontal + Vertical + Rest VO2 = (speed x 0.1) + 0 + 3.5 ml/kg/min VO2 = [(3.5mph x 26.8m/mi) x 0.1] + 0 + 3.5 VO2 = (93.8 m/min x 0.1) + 0 + 3.5 ml/kg/min VO2 = 9.38 + 0 + 3.5 ml/kg/min VO2 = 12.88 ml/kg/min . . . . . .

What’s the Energy Cost? . 70 kg woman walks at 3.5 mph at no grade VO2 = 12.88 ml/kg/min Kcal/min = . 12.88 ml kg*min 70 kg 0.005 kcal 1 ml = 4.508 kcal/min How long must she walk to expend 560 kcal? 4.508 kcal 1 min = 560 kcal X min 560 4.508 = 124 min

Second Stage of Bruce Protocol 90 kg man walks at 3.4 mph at 14% grade VO2 = Horizontal + Vertical + Rest VO2 = (speed x 0.1) + (speed x grade x 1.8) + 3.5 VO2 = [(3.4mph x 26.8m/mi) x 0.1] + (speed x grade x 1.8) + 3.5 VO2 = (91.12 m/min x 0.1) + (91.12 x .14 x 1.8) + 3.5 VO2 = 9.11 + 22.96 + 3.5 ml/kg/min VO2 = 35.57 ml/kg/min . . . . . .

Individualized Protocol 60 kg man running at 7 mph at 14% grade VO2 = Horizontal + Vertical + Rest VO2 = (speed x 0.2) + (speed x grade x 0.9) + 3.5 VO2 = [(7mph x 26.8m/mi) x 0.2] + (speed x grade x 0.9) + 3.5 VO2 = (187.60 m/min x 0.2) + (187.6 x .14 x 0.9) + 3.5 VO2 = 37.52 + 23.64 + 3.5 ml/kg/min VO2 = 64.66 ml/kg/min . . . . . .

Another Individualized Protocol 60 kg woman jogging at 3.2 mph at 2% grade VO2 = Horizontal + Vertical + Rest VO2 = (speed x 0.2) + (speed x grade x 0.9) + 3.5 VO2 = [(3.2mph x 26.8m/mi) x 0.2] + (speed x grade x 0.9) + 3.5 VO2 = (85.76 m/min x 0.2) + (85.76 x .02 x 0.9) + 3.5 VO2 = 17.15 + 1.54 + 3.5 ml/kg/min VO2 = 22.19 ml/kg/min . . . . . .

What’s the Energy Expenditure? 60 kg woman walks at 3.2 mph at 2% grade VO2 = 22.19 ml/kg/min Kcal/min = . 60 kg 22.19 ml kg*min-1 0.005 kcal 1 ml = 6.66 kcal/min How long must she walk to expend 560 kcal? 6.66 kcal 1 min = 560 kcal x min 560 6.66 = 84 min

Cycle Ergometer Protocols Manipulate workload through cadence (rpm) and resistance (kp, W). ACSM leg ergometry equations estimate metabolic cost of exercise (energy expenditure). Power = force x distance/time Power expressed as kpm/min or W. Distance is 6 m for Monark and Bodyguard ergometers. (continued)

Cycle Ergometer Protocols (continued) Electrically braked ergometers allow variable cadences for any workload. Mechanically braked ergometers require close monitoring of cadence. Cadence based on client fitness level and cycling experience. 60 rpm produces highest VO2 max compared to other specific cadences. .

What’s the Energy Expenditure? 80 kg man cycling at 100 W VO2 = Resistance pedaling + Unloaded pedaling + Rest VO2 = [(100W / 80kg)x 10.8] + 3.5 + 3.5 ml/kg/min VO2 = (1.25 x 10.8) + 3.5 + 3.5 VO2 = (13.5) + 3.5 + 3.5 ml/kg/min VO2 = 13.5 + 7 ml/kg/min VO2 = 20.5 ml/kg/min . . . . . . (continued)

What’s the Energy Expenditure? (continued) 60 kg woman cycling at 2 kp with cadence of 60 rpm VO2 = Resistance pedaling + Unloaded pedaling + Rest Power output = 2kp/min * 6m/rev * 60 rpm = 720 kpm/min VO2 = [((720/6) / 60kg)] x 10.8] + 3.5 + 3.5 ml/kg/min VO2 = [((120/60) x 10.8)] + 3.5 + 3.5 VO2 = (21.6) + 3.5 + 3.5 ml/kg/min VO2 = 21.6 + 7 ml/kg/min VO2 = 28.6 ml/kg/min . . . . . .

Tips for Using Ergometer Protocols For GXTs, confirm steady state HR attained prior to stage change. If half of terminal stage is not completed, use resistance and cadence (power output) from prior stage for VO2 calculations. .

Other Testing Protocols . Step tests: Several exist; require use of metronome; VO2 calculations are based on step height and cadence. Recumbent stepper: Alternative for testing those with neuromuscular conditions affecting gait, coordination, and balance. Stair stepper: Good for aerobic step practitioners. Rowing ergometer: One exists for noncompetitive or unskilled rowers.

Submaximal Protocols Not direct assessments of cardiorespiratory capacity May be more practical than maximal exertion protocols Can be performed on many modalities Can involve multiple stages or just one Can determine VO2 via calculations or nomograms Rely on underlying assumptions .

Submaximal Assumptions Steady-state HR is achieved and is consistent for work rate. Relationship between HR and VO2 is linear for HRs between 110 and 150 bpm. Mechanical efficiency is the same for all tested. HRmax is similar for all of same age. .

Field Tests Practical Inexpensive Expedient Easy to administer Good for assessing numerous people simultaneously Suitable for a variety of settings Generally based on postexertion HR measures Least desirable manner of assessing cardiorespiratory fitness Not for diagnosing CHD

Testing Children Treadmills are a better modality than cycles. ACSM recommends modified Balke or modified Bruce protocols with 2-minute stages. Field tests may be used.

Testing Older Adults Use an extended warm-up at a low exertion starting stage. Be ready to adjust treadmill speed for client safety. May need to adjust grade and not speed. Target a total test time of 8 to 12 minutes. Extend stage duration to allow steady-state HR achievement. Cycle ergometry may be preferable for client safety and comfort. Field tests are also a possibility.