Pre-exercise Screening for Minimizing Cardiovascular Risk During Testing

Exercise testing can pose a risk to the patient, so exercise testing must have clear indications, and any contraindications must be ruled out. On the other hand, earlier guidelines for exercise testing in patients, particularly those with cardiac conditions, were too conservative.¹ Patients can be exercised aggressively provided that the indications are based on a comprehensive assessment and a judiciously selected exercise test and protocol and provided that the patient is appropriately monitored throughout testing. The American College of Sports Medicine (ACSM)² has developed an algorithm (Figure 19-1, A) to determine the risk for cardiovascular events during exercise testing (Table 19-1) as well as guidelines for test selection and level of supervision required based on the risk assessment (Figure 19-1, B). As shown in Figure 19-1, A, patients with known cardiovascular, metabolic, or pulmonary disease are classified as having a high risk for sustaining a cardiovascular event during exercise. For these individuals, a comprehensive medical examination and physician-supervised exercise testing is recommended before starting a moderate or vigorous intensity exercise program (see Figure 19-1, B). For individuals who do not have the conditions listed above, the remainder of the algorithm describes how patient signs and symptoms and coronary artery disease risk factors determine the risk classification and exercise testing and supervision requirements. Physical therapists need to screen patients systematically before exercise testing or prescription.

Table 19-1

Cardiovascular Risk Factor Threshold for Risk Stratification

	Risk Factors	Defining Criteria
Positive	Age	Men ≥45 years; Women ≥55 years
	Family history	Myocardial infarction, coronary revascularization, or sudden death before 55 years of age in father or other male first-degree relative, or before 65 years of age in mother or other female first-degree relative
	Cigarette smoking	Current cigarette smoker or those who quit within the previous 6 months or exposure to environmental tobacco smoke
	Sedentary lifestyle	Not participating in at least 30 minutes of moderate intensity (40% to 60% ) physical activity on at least 3 days of the week for at least 3 months
	Obesitya	Body mass index: ≥30 kg × m2 – or – Waist girth:  >102 cm (40 inches) for men  >88 cm (35 inches) for women
	Hypertension	Systolic blood pressure ≥140 mm Hg and/or diastolic ≥90 mm Hg, confirmed by measurements on at least two separate occasions, or on antihypertensive medication
	Dyslipidemia	Low-density lipoprotein (LDL-C) cholesterol ≥130 mg × dL-1 (3.37 mmol × L-1) – or – High-density lipoprotein (HDL-C) cholesterol <40 mg × dL-1 (1.04 mmol × L-1) – or – On lipid-lowering medication If total serum cholesterol is all that is available, use ≥200 mg × dL-1 (5.18 mmol × L-1)
	Prediabetes	Impaired fasting glucose (IFG) = fasting plasma glucose ≥100 mg × dL-1 (5.50 mmol × L-1) – or – Impaired glucose tolerance (IGT) = 2-hour values in oral glucose tolerance test (OGTT) ≥140 mg × dL-1 (7.70 mmol × L-1) but <200 mg × dL-1 (11.00 mmol × L-1) confirmed by measurements on at least two separate occasions
Negative	High-serum HDL cholesterol	≥60 mg × dL-1 (1.55 mmol × L-1)

Note: It is common to sum risk factors in making clinical judgments. If HDL is high, subtract one risk factor from the sum of positive risk factors, because high HDL decreases CVD risk.

^aProfessional opinions vary regarding the most appropriate markers and thresholds for obesity; therefore allied health professionals should use clinical judgment when evaluating the risk factor.

Modified from the American College of Sports Medicine. (2010). Guidelines for exercise testing and prescription, ed 8. Philadelphia: Williams and Wilkins.

Contraindications to Exercise Testing

Contraindications to exercise testing and, in particular, maximal testing are classified as relative or absolute (Box 19-2). Absolute contraindications prohibit the safe conduction of an exercise test, whereas the presence of relative contraindications requires that the test, protocol, physiological variables monitored, or end point of the test be modified. Both the indications for the test and any contraindications must be clearly established before performing an exercise test.

The guidelines used to test and train healthy people with no disease are not directly generalizable to patients with chronic illness who are medically stable. Because of functional impairments in these patients (secondary to cardiopulmonary, cardiovascular, neuromuscular, or musculoskeletal dysfunction), exercise testing and training must be modified. Moreover, patients who are physically challenged experience more subjective symptoms in response to exercise than do healthy people, so monitoring the subjective responses to exercise is essential. The Borg scale of rating perceived exertion can be modified for clinical use to score breathlessness, discomfort, pain, and fatigue (Table 19-3).^9,10 If the end points of the scale have been well described and are understood by the patient, the ratings can be used to compare the patient’s subjective exercise responses over repeated tests. The patient’s subjective reports can be correlated with the exercise response and so can provide a basis for exercise prescription as well as avoiding adverse responses.

The functional impairments and capacities of the patient determine the nature of the exercise test; it can be one of various types, depending on the objective of testing and potential training. If exercise training is an objective of the exercise test, the activity used in the test should be comparable to that to be used in training. Physiological responses and adaptation to exercise are specific to the training stimulus (the specificity-of-exercise principle). Thus if walking is to be the training activity, the test should be a walking test, not a cycling test.

Standardization of Exercise Tests and General Procedures

There are numerous variants of standard exercise tests (Table 19-4). They are categorized as continuous tests or interrupted tests. Continuous tests include maximal and submaximal incremental tests and steady-rate tests; interrupted tests include maximal interval and submaximal interval tests. Interrupted tests are designed for patients with low functional work capacity who cannot sustain prolonged periods of aerobic exercise. These patients can perform more work over time when the workload is intermittent. Specifically, the test allows for alternating fixed periods of work and rest or of high and low intensities of exercise. The proportion of work to rest or high to low exercise intensity is set according to the patient’s level of impairment. One patient, for example, may be able to tolerate 3 to 5 minutes of relatively high-intensity work alternated with bouts of 1 to 2 minutes of low-intensity work, whereas another patient may be able to tolerate only 1 minute of low-intensity work alternated with 10 to 20 seconds of rest.

For maximal standardization and the capacity to perform comprehensive monitoring, stationary exercise modalities such as the treadmill, ergometer, or step are recommended. However, there may be indications to perform an exercise test without a modality, such as the 12-minute walk test or some variant like 6 or 3 minutes.11–13 Standardization of such tests, however, is more challenging. Practice has a significant effect on the results of the 12-minute walk test, so this test must be repeated to achieve a valid test. Also, the instructions for this test are less well standardized clinically than are those for the treadmill or ergometer; this jeopardizes stringent test control and thus must be tightly standardized.¹⁴

Like other diagnostic and testing procedures, the validity and reliability of the exercise test depend on standardization of the procedures. Test validity and reliability can easily be compromised in the absence of repeated testing and controls.15,16 Early ergometer training responses at rest along with submaximal heart rates and reduction in EMG activity in the arms and legs can reflect familiarization.¹⁷ Repeated exercise tests reflect the marked effects of practice. Practice reduces energy output, improves practice-related coordination, and reduces muscle activation.¹⁸ However, with good quality control, a test’s validity and reliability can be maximized, even in patients with severe disease such as chronic heart failure.¹⁹ The pre-exercise test conditions and the preparation and testing procedures must be standardized (Box 19-3).

The test is terminated as soon as the sign or symptom criteria for terminating the test are reached or when the criteria for prematurely terminating the test are reached (Table 19-5). Recording the test conditions and procedures in detail is essential. An example of an exercise test data sheet that can be modified to any testing protocol that includes an exercise modality is shown in Figure 19-2, A. Many patients are unable to be exercise-tested using a modality; these patients can walk on a marked circuit, and the results are recorded on an exercise test data sheet similar to the one shown in Figure 19-2, B. Systematic and detailed record keeping will maximize the test’s validity and its interpretation and will ensure that the same procedures are used in follow-up tests, thereby maximizing the comparability of the results of repeated tests. It is imperative that retests be comparable in every respect to the original test in terms of the preparation of the patient and the procedures.

Table 19-5

Criteria for Prematurely Terminating an Exercise Test

Miscellaneous	Wish of individual for any reason Failure of monitoring equipment
General signs and symptoms	Fatigue Lightheadedness, confusion, ataxia, pallor, cyanosis, dyspnea, nausea, or peripheral vascular insufficiency Onset of angina
Electrocardiogram signs	Symptomatic supraventricular tachycardia Sinus tachycardia displacement (3 mm) horizontal or downsloping from rest Ventricular tachycardia Only gold members can continue reading. Log In or Register to continue Share this: Click to share on Twitter (Opens in new window) Click to share on Facebook (Opens in new window) Related Related posts: Intensive Care Management of Individuals with Secondary Cardiovascular and Pulmonary Dysfunction Cardiovascular and Pulmonary Manifestations of Systemic Conditions Complementary Therapies as Cardiovascular and Pulmonary Physical Therapy Interventions Clinical Evaluation and Assessment of the Cardiovascular and Pulmonary System Stay updated, free articles. Join our Telegram channel Join Tags: Cardiovascular and Pulmonary Physical Therapy Evidence to Practice Jun 11, 2016 | Posted by admin in RESPIRATORY | Comments Off on Mobilization and Exercise: Testing and Training Full access? Get Clinical Tree Get Clinical Tree app for offline access Get Clinical Tree app for offline access