Cardiorespiratory Fitness (Assessment)

Purpose of Evaluation to assess current fitness levels relative to age and sex aid in development of an exercise program identify areas of health/injury risk and possible referral to the appropriate health professional to establish goals and provide motivation to evaluate progress

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 ACSM also state that anyone over 35 with one or more major risk factor should get the physician supervised test. PAR-Q much more relaxed, even up to age 69.

Cardiovascular responses to Acute exercise Cardiac output - rises with work rate Rest 5 L/min; Max 20 L/min Heart rate increases linearly with work rate and O2 consumption (fig 4.10 - Neiman) Max HR = 220 - Age (one standard deviation is +/- 12bpm) Stroke volume rises with exercise to maximum at ~50% of aerobic capacity Rest 60-100ml; exercise 100-120 ml Blood Pressure - Systolic increases linearly with intensity (max 190 - 220 mmHg) - Diastolic may increase slightly (+ 10 mmHg) or not change A-VO2 difference - Rest 5 ml/dl; Max 15 ml/dl Blood flow to working muscle increases with exercise

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 VO2 = HR X SV + (A-V O2) Table 15.2 ACSM 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

O2 consumption Sub max estimates sub-maximal tests have three assumptions Linear relationship between HR, 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 220- age ± 15 bts/min (I have always thought ± 10 for one standard deviation) maximal heart rate stays the same each day for each individual (not true ± 15 bts/min) graph of oxygen uptake versus heart rate is linear mechanical efficiencies are similar Also note that daily variations will affect even a VO2 max test.

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…

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

Cardiorespiratory Capacities METs* VO2max Athlete 16-20+ 56-70+ Physically 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

Stress Tests Bruce protocol is a maximal stress test 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 ECG (electrocardiograph) is used as 30% with confirmed CAD have normal resting ECG but 80% of these abnormalities will show during exercise

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.

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)

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 Hypotensive response may reflect diminished cardiac reserve

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

Rate Pressure Product RPP = SBP x HR 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 - age, clinical status, and medications(b blockers) can influence results This index of relative cardiac work is highly related to directly measured myocardial oxygen consumption and coronary blood flow in healthy subjects over a wide range of exercise intensities

Guidelines for Stopping a Stress Test Repeated presence of premature ventricular contractions (PCVs). 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. Subject requests to stop

Guidelines for Stopping a Stress Test Electrocardiographic changes that include the presence of S-T segment depression of 2 mm or more, AV block - 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.

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 > 260 mmHg Headache, blurred vision, pale, clammy skin, or extreme fatigue. Marked dyspnea (breathlessness) or cyanosis. Dizziness or near fainting, light-headedness or confusion Nausea Failure of equipment

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

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

mCAFT Structure Step for 3 min intervals Take HR at end of each stage 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

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)

Modified CAFT (mCAFT) to be continued? The CAFT was too sub-max for many people.

mCAFT Aerobic Fitness Score = 10 X [17.2 +( 1.29 X O2 cost) - (0.09 X wt (kg)) - (0.18 X age (yrs))] O2 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