Aerobic Exercise Testing

Maximal laboratory measurement & estimation protocols

Learning Objectives

• Discuss the importance of test characteristics: validity, reliability and applicability in normal populations and in clinical settings.

• Explain the components of fitness and performance with reference to basic principles of physics and physiology.

• Explain the rationale of named test protocols and discuss the acute physiological responses to testing.

• Explain and use fitness testing equipment and apply the principles of quality assurance.

Outline

• Introduction

• Terminology

• Common protocols

• Exclusion criteria

• Test termination criteria

• Interpretation of results

• Practical and DAI

Terminology

• Graded Exercise Test (GXT)

• Aerobic Power

• Aerobic Capacity - (VO2max)

• Aerobic Capacity - (VO2peak)

Terminology

• Direct assessment: via pulmonary gas exchange– ‘Measurement’

• Indirect assessment– ‘Estimation’ based on work ouput

What are we testing?

What are we testing?

Protocols

• Bruce

• Modified Bruce

• Balke

• Naughton

• All incremental and continuous

• Discontinuous protocols used mainly in athletes

The Bruce Protocol (1973)

The Modified Bruce

Patient Preparation

• Par-Q

• Written Informed Consent

• Test Briefing– Protocol– RPE– Signals– What to do if things go wrong

• Practise treadmill walking

The Test

• Start– Position feedback– Hand position– Stride, gait and posture

• End of each stage– RPE– Signal– Encouragement

VO2max Achievement Criteria

• A plateau in your VO2 with increased workload.

VO2peak Achievement Criteria

• HR within 10 beats of Max-est

• BLac of 8 – 10 mmol∙l

• R > 1.15

• Failure of VO2 to increase

– Based on estimate from last stage (inappropriate)

Recovery

• Cool down – 3 to 5 minutes or when heart rate and blood pressure

has returned to recommended levels – keep subject moving and monitor condition – Be cautious, problems often occur during recovery

• Take rhythm strip at the end of each recovery minute

• Take blood pressure at 1, 3, 5 minutes into recovery – Note the condition of the patient and abnormalities on

the EKG monitor

Recovery

• Verbally ensure the subject in doing well and has recovered from the test

• Disconnect the subject

• Advise subject – showering, – daily activity, – avoiding extreme temperatures

ACSM Absolute Indications

• Suspicion of a myocardial infarction or acute myocardial infarction (heart attack)

• Onset of moderate/severe angina (chest pain)

• Drop in SBP below standing resting pressure or with increasing workload accompanied by signs or symptoms

• Signs of poor perfusion

ACSM Absolute Indications

• Severe or unusual shortness of breath • CNS (central nervous system) symptoms

– ataxia , vertigo, visual or gait problems, confusion)

• Serious arrhythmias – second / third degree AV block, atrial fibrillation with

fast ventricular response, increasing PVCs, sustained VT)

• Technical inability to monitor the ECG • Patient's request (to stop)

ACSM Relative Indications

• Any chest pain that is increasing • Physical/verbal manifestations of

– shortness of breath – severe fatigue

• Wheezing • Leg cramps or intermittent claudication

(grade 3 on a 4-point scale) • Hypertensive response

– (SBP >260 mm Hg; DBP>115 mm Hg)

ACSM Relative Indications

• Pronounced ECG changes from baseline • >2 mm of horizontal or down sloping ST-

segment depression, or >2 mm of ST-segment elevation (except in aVR)

• Exercise-induced bundle branch block that cannot be distinguished from ventricular tachycardia

• Less serious arrhythmias (abnormal heart rhythms) such as supraventricular tachycardia

Interpretation and Exercise Prescription

• Calculate VO2max and METS. Determine: exercise training intensity heart rate, RPE, or METs

• Have physician interpret ECG recordings

• Consult subject – review test results – exercise prescription – monitor outcome and behavioural changes

Measuring or Estimating VO2max

• Measurement - values• Estimation• Males & Male CHD

– VO2max = 14.76 - 1.379 (T) + 0.451 (T^2) - 0.012 (T^3)

• SEE 3.35 ml.kg-1.min-1

• With Handrail Support– VO2max = 2.282 (T) + 8.545

• SEE 4.92 ml.kg-1.min-1

Estimating VO2max

• Women:– VO2max = 4.38 (T) - 3.90

• ±2.7 ml.kg-1.min-1

• Prediction equations– http://www.exrx.net/Calculators/Treadmill.html

• Full listings:– http://www.exrx.net/Testing/CardioTests.html

Foster et al. MSSE, 28(6):752-756,1996.

Foster et al. MSSE, 28(6):752-756,1996.

Metabolic Equivalents (METs)

Calculating MET equivalents

• 1 MET = 3.5 ml.kg-1.min-1

• Useful in exercise prescription and prognosis– http://www.exrx.net/Calculators/Treadmill.html

Summary

• Protocols

• Measurement– Direct, gold standard

• Estimation– Cost vs. accuracy

• Utilisation– Prescription, Assessment and Prognosis

References.

• Myers et al. The New England Journal of Medicine 346:14:11-16, 2002.

• Sui et al. J Am Geriatr Soc 55:1940–1947, 2007.