Exercise Prescription Methods and Attitudes in Cardiac Rehabilitation

Abstract

In a national survey of 246 cardiac rehabilitation program directors about exercise prescription in the United States, we found maximal exercise testing and interval training were uncommon. We also found substantial variability in the methods used to prescribe exercise intensity, many of which were inconsistent with current guidelines.

Among Patients Taking Beta-Adrenergic Blockade Therapy, Use Measured (Not Predicted) Maximal Heart Rate to Calculate a Target Heart Rate for Cardiac Rehabilitation

“…In the absence of a measured HR max , many CR programs today use a generalized equation (ie, 220 − age) to predict HR max and then subsequently compute a THR using a variety of methods 8. Based on our findings we strongly discourage this approach because 0 to (at best) ≤61% of patients would be prescribed a THR that falls within current guidelines using the HR reserve method (Table 2, shaded column).…”

“…If an exercise test is not available but CR staff believe information from such will help set an exercise intensity that best serves the needs of a patient, then CR programs should establish a workflow whereby a test can be completed soon after a patient starts in CR; a practice that is consistent with the guidelines for using stress testing 13,14. That said, we recognize that completing a GXT or CPX for CR purposes only is ( a ) not common today8 and ( b ) difficult to operationalize for many CR programs.…”

“…If obtaining results from a recently completed GXT or CPX is not a realistic option to gather measured HR max , then we recommend using validated subjective methods of perceived effort to guide exercise intensity in CR, such as RPE or the talk test 7–10,21–24. Regarding RPE, this method for guiding exercise intensity in CR is common,8 yet we suggest caution with its use because the method is known to be associated with its own operational challenges and a possible incorrect training stimulus 18. Specifically, care should be taken when instructing patients about how to interpret and apply RPE correctly, to be sure the biologic training stimulus imposed is commensurate with patient self-reported level of perceived effort 25.…”

“…The use of an equation to predict HR max is a potentially unsafe and incorrect practice because predicted HR max is known to differ from measured HR max 8–10. Additionally, most patients in CR take a βB, which then results in the 220 − age equation generating a prescribed THR that is above guideline recommendations (ie, too intense).…”

“…7 To be properly used in CR, this method requires the direct measurement of maximal HR (HR max ), collected during a symptom-limited graded exercise stress test (GXT) or a cardiopulmonary exercise (CPX) test performed when the patient is taking their medications as prescribed (eg, beta-adrenergic blocking agent, βB). However, only ∼16% of patients enrolled in CR have a recent GXT or CPX available, 8 leading many programs to guide exercise intensity using subjective methods-ratings of perceived exertion (RPE) or talk test-or determine a target HR (THR) based on either resting HR +20 to +30 bpm or an equation that predicts HR max (eg, 220 − age).…”