Clinical Exercise
Testing and
Interpretation
Chapter 4 (11th Ed)
Introduction
• Clinical exercise testing, unlike health-related physical testing, typically involves diagnostic and
prognostic testing or for treatment purposes, for example ECGs (Stress or Rest ECG) while doing a
clinical exercise test
• During a clinical exercise test, individuals are monitored while performing incremental (most
common) or constant work rate exercise using standardized protocols and procedures and
typically using a treadmill or a stationary cycle ergometer.
• The clinical exercise test typically continues until the individual reaches a sign (e.g., ST-segment
depression) or symptom-limited (e.g., angina, fatigue) maximal level of exertion.
• A clinical exercise test is often referred to as a graded exercise test (GXT), an exercise stress test,
or an exercise tolerance test (ETT). When an exercise test includes the analysis of expired gases
during exercise, it is termed a cardiopulmonary exercise test or metabolic exercise test
Copyright © 2018 American College of Sports Medicine
Indications for a Clinical Exercise Test
• Three general categories
1. Diagnosis ( e.g., presence of disease or abnormal physiologic response)
2. Prognosis (e.g., risk for an adverse event)
3. Evaluation of the physiologic response to exercise (e.g., blood pressure [BP] and
peak exercise capacity).
• A symptom-limited maximal exercise test with electrocardiographic
monitoring only (i.e., without adjunctive cardiac imaging) should initially be
considered when the diagnosis of IHD is not certain, the individual has an
interpretable resting electrocardiogram (ECG) (see “Electrocardiogram”
section), and the individual is able to exercise
Copyright © 2018 American College of Sports Medicine
Indications for a Clinical Exercise Test (cont.)
Current evidence does not support the
routine use of exercise testing (with or
without imaging) to screen for IHD or the risk
of IHD-related events in asymptomatic
individuals who have a very low or low
pretest probability of IHD
Evidence also does not support the routine
use of the test among individuals with a high
pretest probability of IHD based on age,
symptoms, and gender, given that the
diagnosis is generally already known
Copyright © 2018 American College of Sports Medicine
Indications for a Clinical Exercise Test (cont.)
Additional indications that might warrant the use of a clinical exercise test include the assessment of:
• Pulmonary diseases (e.g., chronic obstructive pulmonary disease)
• Exercise intolerance and unexplained dyspnea
• Exercise-induced bronchoconstriction
• Exercise-induced arrhythmias
• Pacemaker or heart rate (HR) response to exercise
• Preoperative risk evaluation
• Claudication in peripheral arterial disease
• Disability evaluation
• Physical activity (PA) counseling
Copyright © 2018 American College of Sports Medicine
Indications for a Clinical Exercise Test (cont.)
• There is an inverse relationship between cardiorespiratory fitness
(CRF) measured from an exercise test and the risk of mortality
• Clinical exercise testing is useful in guiding recommendations for
return to work after a cardiac event as well as developing an exercise
prescription.
• Can be used to estimate peak metabolic equivalents (METs)
Copyright © 2018 American College of Sports Medicine
Conducting the Clinical Exercise Test
Prior to the exercise test
1. Informed consent and patient education on the test and what is expected of them. The results
depends on the patient exerting themselves.
2. Medical history (include current and recent symptoms) and medication should be recorded
3. Absolute and relative contra-indications to testing should be noted (page 116 ACSM 11th edition, Box
4.1 NB)
4. Interpretation of resting ECG before exercise test and ECG
Copyright © 2018 American College of Sports Medicine
Contraindications to Symptom-Limited Maximal Exercise Testing
Absolute Contraindications
Relative Contraindications
• Acute myocardial infarction within 2 d
• Ongoing unstable angina
• Uncontrolled cardiac arrhythmia with hemodynamic
compromise
• Active endocarditis
• Symptomatic severe aortic stenosis
• Decompensated heart failure
• Acute pulmonary embolism, pulmonary infarction, or
deep venous thrombosis
• Acute myocarditis or pericarditis
• Acute aortic dissection
• Physical disability that precludes safe and adequate
testing
• Known obstructive left main coronary artery stenosis
• Moderate to severe aortic stenosis with uncertain
relationship to symptoms
• Tachyarrhythmias with uncontrolled ventricular rates
• Acquired advanced or complete heart block
• Recent stroke or transient ischemia attack
• Mental impairment with limited ability to cooperate
• Resting hypertension with systolic >200 mm Hg or
diastolic >110 mm Hg
• Uncorrected medical conditions, such as significant
anemia, important electrolyte imbalance, and
hyperthyroidism
Box 4.1 in 11th edition
Copyright © 2018 American College of Sports Medicine
Skills and Competencies Needed
According to the ACC and AHA, the nonphysician allied health care professional who administers clinical exercise
tests should:
1.
Have the necessary cognitive skills required to competently supervise clinical exercise tests
•
Box 4.2 (11th edition)
2.
Perform at least 50 exercise tests with preceptor supervision
•
Up to 200 supervised exercise tests before independence has also been recommended
3.
Maintain competency by performing between 25 and 50 exercise tests per year
4.
Conduct maximal clinical tests with a physician being in the immediate vicinity
5.
Physician should provide personal supervision for high-risk patients (See Table 4.2 for the patients that will
need supervision).
Copyright © 2018 American College of Sports Medicine
Copyright © 2018 American College of Sports Medicine
Copyright © 2018 American College of Sports Medicine
Testing Mode and Protocol
• The mode selected for the exercise test can impact the results and should
be selected based on the purpose of the test and the individual being
tested.
• With sign- and symptom-limited maximal exercise tests, it is often
recommended that the selected exercise testing protocol is individualized
and results in a total exercise duration between 8 and 12 min.
• The individual’s age, medical and PA history, exercise tolerance and symptomology
should be considered.
• Examples of protocols - Cycle ergometer, Ramp test, Bruce, Modified
Bruce, Naughton, Modified Naughton.
Copyright © 2018 American College of Sports Medicine
Figure 4.1 (11th edition)
Copyright © 2018 American College of Sports Medicine
Monitoring & Test Termination
• During the test and throughout postexercise recovery, the clinician should monitor the individual for
untoward symptoms, such as light-headedness, angina, dyspnea, claudication (if suspected by history),
and fatigue
• Standardized scales to assess perceived exertion (see Table 3.6 and Figure 4.2), angina, dyspnea, and
claudication (Figure 4.3) may also be used.
• A rating of 3 out of 4 is an indication to stop the test
• A 10-point VAS scale may also be used
• Pulse oximetry provides a noninvasive, indirect measure of arterial oxygen saturation (SpO2)
• Should be used for patients with pulmonary disease
• An absolute decrease in SpO2 ≥5% during exercise is considered an abnormal response suggestive of exercise-induced
hypoxemia
• An SpO2≤80% with signs or symptoms of hypoxemia is an indication to stop a test
Copyright © 2018 American College of Sports Medicine
Monitoring & Test Termination
Copyright © 2018 American College of Sports Medicine
Monitoring & Test Termination
Copyright © 2018 American College of Sports Medicine
Indications for Terminating a Symptom-Limited
Maximal Exercise Test
Absolute Indications
•
•
•
•
•
•
•
•
ST elevation (>1.0 mm) in leads without preexisting Q waves
because of prior MI (other than aVR, aVL, or V1)
Drop in systolic blood pressure of >10 mm Hg, despite an
increase in workload, when accompanied by other evidence of
ischemia
Moderate-to-severe angina
Central nervous system symptoms (e.g., ataxia, dizziness, or
near syncope)
Signs of poor perfusion (cyanosis or pallor)
Sustained ventricular tachycardia or other arrhythmia,
including second- or third-degree atrioventricular block, that
interferes with normal maintenance of cardiac output during
exercise
Technical difficulties monitoring the ECG or systolic blood
pressure
The individual’s request to stop
Relative Indications
•
•
•
•
•
•
•
Box 4.3 (11th edition)
Copyright © 2018 American College of Sports Medicine
•
Marked ST displacement (horizontal or downsloping of >2 mm,
measured 60–80 ms after the J point in an individual with
suspected ischemia)
Drop in systolic blood pressure >10 mm Hg (persistently below
baseline) despite an increase in workload, in the absence of
other evidence of ischemia
Increasing chest pain
Fatigue, shortness of breath, wheezing, leg cramps, or
claudication
Arrhythmias other than sustained ventricular tachycardia,
including multifocal ectopy, ventricular triplets,
supraventricular tachycardia, and bradyarrhythmias that have
the potential to become more complex or to interfere with
hemodynamic stability
Exaggerated hypertensive response (systolic blood pressure
>250 mm Hg or diastolic blood pressure >115 mm Hg)
Development of bundle-branch block that cannot be
distinguished from ventricular tachycardia
SpO2 ≤80%
Post-exercise & Safety
• In conjunction with the lab’s medical director, each laboratory should develop
standardized procedures for the postexercise recovery period.
• Low intensity active recovery is often practiced in order to support venous
return and hemodynamic stability.
• Although exercise test sensitivity for the diagnosis of IHD can be
maximized in a supine position immediately following exercise, this can
result in profound hypotension and dangerous secondary ischemia.
• Although untoward events do occur, clinical exercise testing is generally safe
when performed by appropriately trained clinicians.
Copyright © 2018 American College of Sports Medicine
Interpreting the Clinical Exercise Test
Heart Rate Response
• The normal HR response to incremental exercise is to increase with
increasing workloads at a rate of ≈10 beats  min−1 per 1 MET.
• Equations exist to predict HRmax in individuals who are not taking a adrenergic blocking agent (see Table 5.3).
• HRmax decreases with age and is attenuated in individuals on -adrenergic
blocking agents. All HRmax estimates have large interindividual variability
with standard deviations of 10 beats or more.
Copyright © 2018 American College of Sports Medicine
Interpreting the Clinical Exercise Test
Heart Rate Response (cont.)
• Among individuals referred for testing secondary to IHD, and in the absence of adrenergic blocking agents, failure to achieve an age-predicted HRmax >85% in the
presence of maximal effort is an indicator of chronotropic incompetence and is
independently associated with increased risk of morbidity and mortality.
• A failure of the HR to decrease by >12 beats during the first minute or >22 beats by the
end of the second minute of active postexercise recovery is strongly associated with an
increased risk of mortality in individuals diagnosed with or at increased risk for IHD.
• The rate of decline in HR following exercise (HR recovery) provides independent
information related to prognosis
Copyright © 2018 American College of Sports Medicine
Interpreting the Clinical Exercise Test
Blood Pressure Response
• The normal systolic blood pressure (SBP) response to exercise is an increase with increasing workloads at a rate of ~10 mm Hg per
1 MET
Hypertensive response:
• An SBP >250 mm Hg is a relative indication to stop a test. An SBP ≥210 mm Hg in men and ≥190 mm Hg in women during exercise
is considered an exaggerated response. A peak SBP >250 mm Hg or an increase in SBP >140 mm Hg during exercise above the
pretest resting value is predictive of future resting hypertension.
Hypotensive response:
• A decrease of SBP below the pretest resting value or by >10 mm Hg after a preliminary increase, particularly in the presence of
other indices of ischemia, is abnormal and often associated with myocardial ischemia, left ventricular dysfunction, and an
increased risk of subsequent cardiac events.
Blunted response:
• In individuals with a limited ability to augment cardiac output, the response of SBP during exercise will be slower compared to
normal.
Postexercise response:
• SBP typically returns to preexercise levels or lower by 6 min of recovery. Studies have demonstrated that a delay in the recovery
of SBP is highly related both to ischemic abnormalities and to a poor prognosis.
Copyright © 2018 American College of Sports Medicine
Interpreting the Clinical Exercise Test
Rate Pressure Product
• Rate-pressure product (also known as double product) is calculated by multiplying the values for HR and SBP
that occur at the same time during rest or exercise.
• Rate-pressure product is a surrogate for myocardial oxygen uptake.
• There is a linear relationship between myocardial oxygen uptake and both coronary blood flow and exercise
intensity
• If coronary blood supply is impaired, which can occur in obstructive IHD, then signs or symptoms of
myocardial ischemia may be present.
• The point during exercise when this occurs is the ischemic threshold. Rate-pressure product is a repeatable
estimate of the ischemic threshold and more reliable than external workload
Copyright © 2018 American College of Sports Medicine
Interpreting the Clinical Exercise Test
Electrocardiogram
• Please read page 128 (11th edition) for theory on ECGs, as well as
Appendix B for ECG interpretation
• Will be covered in detail in the CVD submodule (end March-mid April)
Copyright © 2018 American College of Sports Medicine
Interpreting the Clinical Exercise Test
Exercise Capacity
• High exercise capacity is generally indicative of good overall cardiopulmonary health and the absence of
serious limitations in left ventricular function
• Estimating exercise capacity on a treadmill is confounded by several factors, including treadmill experience,
walking efficiency, presence of disease, the exercise protocol used, and use of the handrails for support.
• Expressing V̇O2peak as a percentage of age-predicted normal value is advantageous because exercise
capacity declines with age and is higher among men compared to women
• When expressing exercise capacity as a percentage of age-predicted normal value, it is important that the
equation used is derived from a population representative of the individual tested, that it reflects whether
exercise capacity was measured directly or estimated from the work rate, that it reflects the appropriate
exercise mode used (cycle ergometer or treadmill), and that exercise capacity is expressed appropriately.
Copyright © 2018 American College of Sports Medicine
Interpreting the Clinical Exercise Test
Exercise Capacity (cont.)
• When we are talking about about CRF, we are talking about the integrated functional
capabilities of the heart, blood vessels, lungs, and skeletal muscles to perform work.
• We use VO2max to describe our maximal aerobic abilities, in other words to provide an
indication of our CRF.
• We can describe our exercise capacity in terms of our VO2peak/VO2max or estimated
METs
• VO2max – Refers to our maximal oxygen consumption and can be described as either absolute
(L/min) or relative (ml/kg/min).
• METs – An abbreviation for Metabolic Equivalent. One MET is equivalent to the relative oxygen
consumption at rest. Therefore 1 MET = 3.5 ml/kg/min. These are calculated by dividing the
relative oxygen consumption by 3.5
• For example, if you are exercising at a VO2 of 35 ml/kg/min, you would be exercising at 10 METs.
• METs are therefore also a useful measurement in clinical settings
Copyright © 2018 American College of Sports Medicine
Regression Equations for
calculating age-predicted
VO2max based on height
& weight
Copyright © 2018 American College of Sports Medicine
Measured and Estimated VO2max
• The measurement of VO2max may not always be feasible because
metabolic measurement systems are relatively expensive and require
additional expertise to operate and interpret results
• VO2max can be estimated from exercise test time and from peak
workload
• Metabolic calculations can also be used to estimate VO2max during common
physical activities (Appendix D in 11th edition; Table 6.3 in 10th edition
Example – Calculating estimated VO2 for a
treadmill test using metabolic equations
• Treadmill speed (9km/h), gradient (10%)
• VO2 = 3.5 + (0.2 x speed) + (0.9 x speed x grade)
• VO2 = 3.5 + (0.2 x 9) + (0.9 x 9 x 0.10)
• Note: We must convert from km to m.min (meters per minute)!
• VO2 = 3.5 + (0.2 x 150) + (0.9 x 150 x 0.10)
• VO2 = 3.5 + 30 + 13.5
• VO2 = 47 ml.kg.min-1
• To convert to METs
• METs = VO2/3.5
• METs = 47/3.5
• METs = 13.42
• We can use the values we collect in our clinical exercise tests (VO2, HR, calculated METs, RPE, work rate,
speed, etc) to calculate appropriate training intensity zones for our patients (Chapter 6)
Interpreting the Clinical Exercise Test
Cardiopulmonary Exercise Testing
• A major advantage of measuring ventilatory gas exchange
during exercise is a more accurate measurement of exercise
capacity
• Data may be particularly useful in estimating prognosis and
defining the timing of advanced therapies and procedures in
individuals with heart failure
• Helpful in the differential diagnosis of individuals with
suspected cardiovascular and respiratory diseases
• Particularly useful in identifying whether the cause of
dyspnea has a cardiac or pulmonary aetiology.
Copyright © 2018 American College of Sports Medicine
Interpreting the Clinical Exercise Test
Maximal versus Peak Cardiorespiratory Stress
• Various criteria have been used to confirm that a maximal effort has been
elicited during a GXT
• A plateau in V̇O2 (or failure to increase V̇O2 by 150 mL ∙ min−1) with increased
workload.
• Fallen out of favor because a plateau is not consistently observed during maximal exercise
testing, particularly in individuals with cardiovascular or pulmonary disease (61).
• Failure of HR to increase with increases in workload.
• A postexercise venous lactate concentration >8.0 mmol ∙ L−1
• A rating of perceived exertion (RPE) at peak exercise >17 on the 6–20 scale or >7 on
the 0–10 scale
• A peak RER ≥1.10. Peak RER is perhaps the most accurate and objective noninvasive
indicator of individual effort during a GXT
Copyright © 2018 American College of Sports Medicine
Diagnostic Value of Exercise Testing for the Detection
of Ischemic Heart Disease
• The diagnostic value of the clinical exercise test for the detection of IHD is
influenced by the principles of conditional probability.
• The factors that determine the diagnostic value of exercise testing (and other
diagnostic tests) are the sensitivity, specificity, and predictive value of the test
procedure and prevalence of IHD in the population tested.
Copyright © 2018 American College of Sports Medicine
Diagnostic Value of Exercise Testing for the Detection
of Ischemic Heart Disease
Sensitivity, Specificity, and Predictive Value
• Sensitivity: the ability to positively identify individuals who truly have IHD
• Specificity: the ability to correctly identify individuals who do not have IHD
• The predictive value is a measure of how accurately a test result correctly
identifies the presence or absence of IHD and is calculated from sensitivity and
specificity.
• These calculations yield true positive and false negative results.
Copyright © 2018 American College of Sports Medicine
Diagnostic Value of Exercise Testing for the Detection
of Ischemic Heart Disease
Copyright © 2018 American College of Sports Medicine
Diagnostic Value of Exercise Testing for the Detection
of Ischemic Heart Disease
Copyright © 2018 American College of Sports Medicine
Diagnostic Value of Exercise Testing for the Detection
of Ischemic Heart Disease
Copyright © 2018 American College of Sports Medicine
Clinical Exercise Test Data and Prognosis
Duke Score/Nomogram
• Considers exercise
capacity, the magnitude
of ST-segment
depression, and the
presence and severity of
angina pectoris.
• The calculated score is
related to annual and 5-yr
survival rates
Copyright © 2018 American College of Sports Medicine
Clinical Exercise Testing with Imaging
• When the resting ECG is abnormal, exercise testing may be coupled
with other techniques designed to either augment or replace the
ECG when resting abnormalities (Box 4.4) make evaluation of
changes during exercise impossible.
• When exercise testing is coupled with myocardial perfusion imaging
(e.g., nuclear stress test) or echocardiography, all other aspects of
the exercise test should remain the same, including HR and BP
monitoring during and after exercise, symptom evaluation, rhythm
monitoring, and symptom-limited maximal exertion.
Copyright © 2018 American College of Sports Medicine
Clinical Exercise Testing with Imaging
• When the resting ECG is abnormal, exercise testing may be coupled with
other techniques designed to either augment or replace the ECG when
resting abnormalities (Box 4.4) make evaluation of changes during
exercise impossible.
• When exercise testing is coupled with myocardial perfusion imaging (e.g.,
nuclear stress test) or echocardiography, all other aspects of the exercise
test should remain the same, including HR and BP monitoring during and
after exercise, symptom evaluation, rhythm monitoring, and symptomlimited maximal exertion.
• Echocardiographic examination allows evaluation of wall motion, wall
thickness, and valve function
Copyright © 2018 American College of Sports Medicine
Field Walking Tests
• Non-laboratory-based clinical exercise tests are also frequently used in
individuals with chronic disease.
• These tests are generally classified as field or hallway walking tests and
are typically considered submaximal.
• Similar to maximal exercise tests, field walking tests are used to evaluate
exercise capacity, estimate prognosis, and evaluate response to treatment.
• Tests include 6-MWT, incremental, and endurance shuttle walk tests.
Copyright © 2018 American College of Sports Medicine
Next:
• Chapter 5 (11th edition) – General Principles of Exercise Prescription
• Please read through the whole chapter in preparation for the next
classes and activities.
Copyright © 2018 American College of Sports Medicine