cardiorespiratory testing. maximal oxygen uptake aka vo 2 max criterion measure of cardiorespiratory...

Cardiorespiratory Testing

Maximal Oxygen Uptake

• AKA VO2 Max

• Criterion measure of cardiorespiratory fitness

• Product of maximal cardiac output and arterial-venous oxygen difference

• Directly related to functional capacity of the heart

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• Direct measurement– Open-circuit spirometry

• Pulmonary ventilation

• Expired O2 and CO2 fractions

• Indirect methods– Estimation techniques

– VO2 values correlated with intensities reached• Similarities in fitness levels

• Similarities in age and gender

• Regression equations used to predict VO2


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• Step tests– Little equipment or skill needed

– Short duration test – less than 5 minutes

– Requires some balance

– Difficult for extremely deconditioned



• Field tests – practical (mass testing)– Cooper 12 minute run

» Requires maximal effort & motivation

» Unmonitored – danger for at-risk?

– Rockport 1 mile walk

» Requires maximal effort & motivation

» Unmonitored but walking vs. running decreases danger



• Treadmill tests– Accommodates all fitness levels – speed changes

– Requires skill and balance for some – practice?

– Difficult to measure BP



• Cycle ergometer tests– Easy to take BP measurements

– Non weight bearing – accommodates extremely weak

– Small work rate adjustments can be made

– Familiar skill – but not a common activity

– Severe localized fatigue - motivation

– Specific pedal cadence is required - motivation


• Maximal Exercise Tests– Advantage

• True maximal capacity can be measured

• Increased sensitivity in Dx of CAD in asymptomatic

– Disadvantage• Volitional fatigue

– do they know maximum?

– risk of injury

• Physician supervision*

• Emergency equipment*


• Maximal Exercise Tests– Incremental workloads– Steady state not required

• “Quick and dirty”

• Just max is the goal

– Prolonged – other measures along the way• Ventilatory threshold

• Lactate threshold


• Submaximal Exercise Tests– Assumptions

• Steady is state reached at each work rate

• Linear relationship between HR and work rate

• Maximal HR is uniform for every age

• Predict max from slope of line


Submaximal Testing

• Keys to success– 2-3 min warm-up and equipment acquaintance– Monitor HR & BP near the end of each stage– Perceived exertion (6-20 or 1-10 scale)– Monitor subject’s/client’s appearance– Terminate at 85% of age-predicted max HR, or

70% of HR reserve, or if problems arise– Allow warm-down & monitor

• Test Termination Criteria in Low-risk adults (Box 4-5)– ***Subject requests to stop***

– **Failure of testing equipment**

– Onset of angina – pain associated with ischemia

– Significant rise or drop in BP

– Signs of poor perfusion – pallor

– Failure of HR to increase with workload increase

– Noticeable change in heart rhythm

– Severe fatigue

Submaximal Testing

• Cycle Ergometer Tests– Astrand-Rhyming Cycle Ergometer Test (page 70)

• Single stage test – target HR from 125-170

• Work Rate – (@ 50 rpm)– Men – unfit 300 or 600, fit 600 or 900 kgm/min

– Women – unfit 300 or 450, fit 450 or 600 kgm/min

• Heart rate taken @ 5th & 6th min. – average them

• Use of nomogram to estimate max VO2 (Figure 4-1)

• Correct VO2 max by multiplying correction factor for age difference in max HR

Submaximal Testing

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• Cycle Ergometer Tests– YMCA Cycle Ergometry Test (page 74)

• 2 - 4 stage continuous exercise

• Branching – if ___ Hr, then ___ intensity

• Heart rate taken @ 2nd & 3rd min. of each stage

• HR must be within 6 beats to go to next stage

• HR must be between 110 and 85% age predicted max

• Plot HRs of last min. then extrapolate to max HR

• Line to predicted work rate at max VO2

• Calculate a predicted VO2 (Appendix D)

Submaximal Testing

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Prediction Line

220-age

Work Rate

Max HR

Max Work Rate

Submax 1

Submax 2

Evaluation of Results

• Compare predicted VO2 to norm table (table 4-8)

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Example

• Male, Age = 45

• 1st stage yields HR of 98

• 2nd stage yields HR of 121

• 3rd stage yields HR of 143

• Age predicted max HR = 175

• 85% of max HR = 149

• Predicted max = ? Plot to find

Example

• Use graph to plot predicted work rate at max HR

• Used predicted max work rate for calculation of predicted max VO2

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Maximal Testing

• Purpose– Diagnosis of CAD– Prognosis of client regarding disease– Finding functional capacity for prescription

(CRF – Cardiorespiratory Function)

• Physician Supervised?– Low risk & men < 45 yr / women < 55 yr– Moderate & High risk

Maximal Testing• Personnel

– “Experienced paramedical personnel”– ACSM Exercise Specialist Certified? KSA’s

1. Exercise Physiology and Related Exercise Science2. Pathophysiology and Risk Factors3. Health Appraisal, Fitness and Clinical Exercise Testing4. Electrocardiography and Diagnostic Techniques5. Patient Management and Medications6. Medical and Surgical Management7. Exercise Prescription and Programming8. Nutrition and Weight Management9. Human Behavior and Counseling10. Safety, injury Prevention, and Emergency Procedures11. Program Administration, Quality Assurance, and Outcome

Assessment

Maximal Testing

• Work Rate Changes– Incremental Format

• 1 minute – 3 minutes• Large intensity changes• Time to reach steady state

– Ramp Format• ~ 20 sec stages• Small intensity changes• Smoother – non-steady state

Maximal Testing

• Clinical– Treadmill

• Bruce Protocol – most common

– large metabolic demand increments

– best for more fit subjects

– 3 min stages

– increases in speed & grade

Maximal Testing

• Clinical– Treadmill

• Balke-Ware – small work increments

– best for less fit subjects

– 1 min stages

– speed remains at 3.3 mph

– increases in grade only by 1% each stage

Maximal Testing

• Sequence of Measures– HR (ECG), BP, RPE, Familiarization, Termination– Box 4-4

• Pre

• Exercise

• Posttest

Maximal Testing

• Indications for Terminating Test– Absolute

• Decreased medical status• Equipment Failure• Request to stop

– Relative• Change in hemodynamic function• Change in ECG • Fatigue / Chest Pain

Maximal Testing

• Symptomatic– Angina Scale

• 1+ Light, barely noticeable

• 2+ Moderate, bothersome

• 3+ Moderately severe, very uncomfortable

• 4+ Most severe or intense pain ever experienced

– A 3+ would indicate stopping a test

Maximal Testing

• Functional Aerobic Impairment– %FAI = (Predicted VO2 – Observed VO2) x 100

Predicted VO2

. ..

Maximal Testing

• Metabolic Equivalents – METs

• Multiples of VO2 at rest - 3.5 ml/kg/min

• Predicted average max VO2 in METs

– Men= (57.5 - .445 x age) / 3.5– Women= (42.3 - .356 x age) / 3.5

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Maximal Testing

• Performance– Determine functional capacity

• Velocity at max for prescription and program assessment

• HR at max for prescription and program assessment

• Power at max for prescription and program assessment

Maximal Testing

• Performance– Methods

• Max only– “Quick & dirty” – rapid rise in intensity until max

– 8- 12 minutes of testing

– No need for steady state

– max is goal without fatigue from time

Maximal Testing

• Treadmill– Protocol

• Ramp or incremental stages

• Alternate speed and / or grade

• Limitation should be physiological not psychological

Maximal Testing

• Cycle Ergometer– Protocol

• Ramp or incremental stages

• Maintain pedal cadence

• Increase tension

• Seated & legs only – no standing or arm assistance

• Limitation should be physiological not psychological

Maximal Testing

• Max VO2 Determination Criteria

– Caveat 1. Use of large muscle groups – Caveat 2. Activity specific to “athlete’s” sport

1. No increase in VO2 with increase in work rate

2. RER > 1.15

3. HR during final stage + 10 beats of predicted HR

* Blood lactate concentration > 8 mmoles/liter

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Max VO2

Work Rate

VO

2 (m

l/kg/

min

)

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Maximal Testing

• PEAK VO2

– Highest VO2 reached without meeting caveats

– Highest VO2 reached without meeting 2 of 3 criteria

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Maximal Testing

• Threshold Determination– OBLA – rapid blood lactate accumulation– T-vent - non-linear ventilation increase– Protocol

• Smaller intensity increments – not too small!

• Even intensity increments

• Minute by minute measures – “catch” the inflection point

• May last too long to achieve max (fatigue)

Ventilatory Threshold

Work Rate

Ven

tilat

ion

(ml/m

in)

T-vent

Supra-maximal Testing

• Wingate Anaerobic Power Test– Energy supply beyond aerobic metabolism– Protocol

• Cycle ergometer• 30 second ride at maximal cadence• Load = 7.5% to 10% of body mass (kg)• Determines peak power (watts)• Determines average power• Determines %Power Decline

Supra-maximal Testing

• Wingate Anaerobic Power Test– Indices

• Phosphagen stores

• Glycolytic system

• Buffering capacity

• Motivation & capacity to tolerate discomfort

• “Kick” at the end of a race or surge during the race

• Power to weight ratio (relative power)

Questions?

cardiorespiratory testing. maximal oxygen uptake aka vo 2 max criterion measure of cardiorespiratory...

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