Cardiorespiratory Fitness Purpose of Evaluation - PowerPoint PPT Presentation

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Cardiorespiratory Fitness Purpose of Evaluation

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

  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 O2 consumption • Max HR =220 - Age (one standard deviation is +/- 12bpm)

  8. Stroke volume rises with exercise to maximum at ~50% • Rest 60-100ml; exercise 100-120 ml

  9. Blood Pressure - Systolic increases linearly with intensity (max 190 - 220 mmHg) -Diastolic may increase slightly (+ 10 mmHg) or not change

  10. (a-v)O2 difference - Rest 5 ml/dl; Max 15 ml/dl

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

  12. Oxygen Consumption • Maximal oxygen consumption is most widely recognized measure of cardiopulmonary fitness • VO2 Max - highest rate of O2 use that can be achieved at maximal exertion • Fick Equation - VO2 = HR X SV X (a-v) O2 • Table 3.3 ACSM • Absolute VO2- L/min or ml/kg/min (relative to body weight) • Relative VO2- given as % of VO2 max

  13. 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

  14. O2 consumption Sub max estimates • sub-maximal tests have four assumptions • Linear relationship between HR and O2 uptake • Valid between 110 and 150 bpm • Linear relationship between O2 uptake and workload • That the max HR at a given age is uniform • That the mechanical efficiency (O2 uptake at a given workload) is the same for everyone • Not entirely accurate - can result in 10-15% error in estimating VO2 max • Tend to overestimate in highly trained, underestimate in untrained

  15. 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 One Mile Walking Test • Treadmill walk test • Cooper test • 1.5 mile test Caution client to stop if feeling dizzy, nauseous, very short of breath…

  16. Metabolic Equivalent (MET) • Absolute resting O2 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

  17. Cardiorespiratory Capacities METs*VO2max (ml/kg/min) Athlete 16-20+ 56-70+ Active 10-15 35-53 Sedentary 8-10 28-35 Cardiac Patient - Class II 5-7 18-25 - Class III 3-5 11-18 - Class IV <3 <11

  18. 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 VO2 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

  19. 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.

  20. 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)

  21. Blood Pressure Response • normal for systolic to rise to 190-220 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 20-30 mmHg,Or SBP drops (20 mmHg) • Correlated with myocardial ischemia, left ventricular dysfunction and risk of cardiac events

  22. Heart Rate Response • average resting HR 60-80 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

  23. 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(b blockers) can influence results

  24. 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.

  25. 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

  26. Interpretation of Bruce • Prediction equations for VO2 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

  27. CSEP-PATH - 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

  28. 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

  29. Before Starting mCAFT • Ensure Par-Q and consent completed • Determine starting stage p 62 CSEP-PATH • have clients practice • determine ceiling HR for that client • 85% HR max = 0.85(220-age) • Supervise client during recovery

  30. mCAFT • V02 max= [17.2 +( 1.29 X O2 cost) - (0.09 X wt (kg)) - (0.18 X age (yrs))] • O2 cost is determined using table on p 63 CSEP-PATH • 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 rating p 68