1 Cardiorespiratory Fitness Purpose of Evaluation educate client about current fitness levels relative to age and sex Inspire individuals to take action to improve their health-related physical fitness Use data to develop an individualized exercise program identify areas of health/injury risk and possible referral to the appropriate health professional to establish goals and provide motivation to evaluate effectiveness of exercise program

2 Fig. 1. The movement continuum, illustrating the different focus of sedentary physiology and exercise physiology. METs, metabolic equivalent tasks. Prolonged uninterrupted sitting, independent of physical activity may be a risk factor for chronic disease.

3 Fig. 3. Illustration of accelerometer data portraying an active couch potato (moderate to vigorous intensity physical activity meeting guidelines considered ‘‘physically active’’ but also a high level of sedentary behaviour) versus an active non-couch potato (similar level of moderate to vigorous intensity physical activity but low level of sedentary behaviour). (From Dunstan et al. 2010a, reproduced with permission of Touch Briefings, European Endocrinology, Vol. 6, p. 21, # 2010.)

4 Fig. 4. Portrayal of significantly different patterns of breaks in sedentary time, based on accelerometer data from 2 different individuals (a ‘‘prolonger’’ and a ‘‘breaker’’). (From Dunstan et al. 2010a, reproduced with permission of Touch Briefings, European Endocrinology, Vol. 6, p. 21, # 2010.)

5 Pretest and Safety Procedures we have already discussed screening in this area (HR, BP, observation) note the very cautious stance in the USA (everyone over 45 should have physician supervised graded exercise test) written emergency procedures written consent Cardiovascular responses to Acute exercise are described on the following slides

6 Cardiac output - rises with work rate –Rest 5 L/min; Max 20 L/min

7 Heart rate increases linearly with work rate and O 2 consumption –Max HR = Age (one standard deviation is +/- 12bpm)

8 Stroke volume rises with exercise to maximum at ~50% Rest ml; exercise ml

9 Blood Pressure - Systolic increases linearly with intensity (max mmHg) -Diastolic may increase slightly (+ 10 mmHg) or not change

10 (a-v)O 2 difference - Rest 5 ml/dl; Max 15 ml/dl

11 Blood flow to working muscle increases with exercise - from 20% to 85% of Q

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13 Oxygen Consumption Maximal oxygen consumption is most widely recognized measure of cardiopulmonary fitness VO 2 Max - highest rate of O 2 use that can be achieved at maximal exertion –Fick Equation - VO 2 = HR X SV X (a-v) O 2 –Table 3.3 ACSM –Absolute VO 2 - L/min or ml/kg/min (relative to body weight) –Relative VO 2 - given as % of VO 2 max

14 Oxygen Consumption Direct measurement of maximal oxygen uptake is the most accurate - Douglas Bag –Can also be estimated from peak work rate –Treadmill speed and grade, cycle work rate

15 O 2 consumption Sub max estimates sub-maximal tests have four assumptions –Linear relationship between HR and O 2 uptake Valid between 110 and 150 bpm –Linear relationship between O 2 uptake and workload –That the max HR at a given age is uniform –That the mechanical efficiency (O 2 uptake at a given workload) is the same for everyone Not entirely accurate - can result in % error in estimating VO 2 max –Tend to overestimate in highly trained, underestimate in untrained

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17 Sub-maximal Tests We have done (or will do) the following sub-max tests YMCA sub-maximal bicycle test Sub-maximal step test (mCAFT) Rockport Fitness Walking Test Cooper test 1.5 mile test Caution client to stop if feeling dizzy, nauseous, very short of breath…

18 Metabolic Equivalent (MET) Absolute resting O 2 consumption –250 ml / min divided by body weight An MET is the average amount of oxygen consumed while at rest. It is used a lot in ACSM exercise prescription guidelines. MET = 3.5 ml / kg min Capacity to increase work rate above rest is indicated by number of METs in max test –Sedentary can increase to 10, an athlete up to 23 MET

19 Cardiorespiratory Capacities METs* VO 2 max (ml/kg/min) Athlete Active Sedentary Cardiac Patient - Class II Class III Class IV <3<11

20 Stress Tests Bruce protocol is a maximal stress test –3 min stages on treadmill Increase speed and percent grade (~3.5 MET / stage) –Used as a diagnostic test for coronary heart disease and estimating VO 2 max must be cautious as Coronary Heart Disease is the #1 killer in Canada –if client has positive PAR-Q or is over 45 in the states need physician to be present ECG (electrocardiograph) is used during stress test, as 30% with confirmed CAD have normal resting ECG –but 80% of these abnormalities will show during the stress of exercise

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23 Why Use Stress Tests? To establish, from ECG, a diagnosis of heart disease and to screen for "silent" coronary disease in seemingly healthy individuals. To reproduce and assess exercise-related chest symptoms. To screen candidates for preventive and cardiac rehabilitative exercise programs. To detect abnormal blood pressure response To define functional aerobic capacity and evaluate its degree of deviation from normal standards.

24 Exercise-Induced Indicators of CHD Angina Pectoris present 30% of time. Electrocardiographic Disorders –S-T segment depression Cardiac Rhythm Abnormalities –premature ventricular contractions –ventricular fibrillation Other Indices of CHD –blood pressure (hypertensive and hypotensive) –heart rate (tachycardia or bradycardia)

25 Blood Pressure Response normal for systolic to rise to mmHg normal for diastolic to increase by 10 mmHg (can actually drop or stay the same) systolic should not exceed 260 mmHg diastolic increase >20 mmHg = hypertensive exertional hypotensive response –failure of Systolic pressure to rise by at least mmHg, Or SBP drops (20 mmHg) –Correlated with myocardial ischemia, left ventricular dysfunction and risk of cardiac events

26 Heart Rate Response average resting HR bpm but males usually 7-8 beats/min lower than females tachycardia early in exercise is indicator of potential problems bradycardia during exercise could be sinus node malfunction or other heart disease problems - or extreme fitness Remember max HR declines with age

27 Rate Pressure Product Commonly used estimate of myocardial workload and resulting oxygen consumption. RPP = SBP x HR Where: RPP = rate pressure product SBP = systolic blood pressure HR = heart rate expect RPP to rise to > 25,000 (minimum adequate) - age, clinical status, and medications(  blockers) can influence results

28 Guidelines for Stopping a Stress Test Repeated presence of premature ventricular contractions (PVCs). Progressive angina pain regardless of the presence or absence of ECG abnormalities consistent with angina. An extremely rapid increase in heart rate may reflect a severely compromised cardiovascular response. Electrocardiograph changes that include; –S-T segment depression of 2 mm or more, –AV block, PVC Failure of heart rate or blood pressure to increase with progressive exercise –or a progressive drop in systolic blood pressure (20mmHg) with increasing work load.

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31 Guidelines for Stopping a Stress Test An increase in diastolic pressure of 20 mm Hg or more, a rise above 115 mm Hg. Rise in systolic pressure > 250 mmHg Headache, blurred vision, pale, clammy skin, or extreme fatigue. Subject requests to stop Marked dyspnea (breathlessness) or cyanosis. Dizziness or near fainting, light-headedness or confusion Nausea Failure of equipment

32 Interpretation of Bruce Prediction equations for VO 2 max available based on activity and health status and gender (see lab book) Outcomes –True positive - correctly predicts problem –False Negative - results are normal - patient has disease –True Negative - results normal - no disease –False Positive - abnormal test - no disease With any positive results secondary tests are performed to confirm diagnosis

33 CPAFLA - mCAFT mCAFT- modified Canadian Aerobic Fitness Test –Ability and efficiency of lungs, heart, bloodstream, and exercising muscles in getting oxygen to the muscles and putting it to work. Benefits of larger aerobic capacity –daily activities –reserve for recreation and emergencies decline 10 % per decade after age 20 –regular vigorous activity to deter this decline

34 mCAFT Structure Step for 3 min intervals –predetermined height and frequency (work rate) –Note - final stages use one large step up from back of steps Men stages 7 and 8, women stage 8 Take HR at end of each stage –assess if client will continue based on ceiling HR (fig 7-10) –utilize heart rate monitor, or radial pulse Take BP and HR after recovery –to determine if client is back to resting levels before release –Cuff can be attached before trial, or quickly after

35 Before Starting mCAFT Ensure Par-Q and consent completed Determine starting stage Fig’s 7-8,9 have clients practice (p. 7-26) note ceiling HR for that client (fig 7-10) Upon completion client walks around for 2 minutes Sit down and get recovery BP and HR (set times listed in CPAFLA)

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38 mCAFT Aerobic Fitness Score = 10 X [17.2 +( 1.29 X O 2 cost) - (0.09 X wt (kg)) - (0.18 X age (yrs))] –O 2 cost is determined using Fig 7-11 The final heart rate is not considered, only the stage attained in assessing benefit zone –Heart rate can be used to determine improvement upon reappraisal if client does not move zones Determine health benefit zone using fig 7-12

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