Authors

1. Keteyian, Steven J. PhD
2. Steenson, Katherina MS
3. Grimshaw, Crystal MS
4. Mandel, Noah MS
5. Koester-Qualters, Wanda MS
6. Berry, Robert MS
7. Kerrigan, Dennis J. PhD
8. Ehrman, Jonathon K. PhD
9. Peterson, Edward L. PhD
10. Brawner, Clinton A. PhD

Abstract

Purpose: Among patients in cardiac rehabilitation (CR) on beta-adrenergic blockade ([beta]B) therapy, this study describes the frequency for which target heart rate (THR) values computed using a predicted maximal heart rate (HR_max), correspond to a THR computed using a measured HR_max in the guideline-based heart rate reserve (HR_reserve) method.

Methods: Before CR, patients completed a cardiopulmonary exercise test to measure HR_max, with the data used to determine THR via the HR_reserve method. Additionally, predicted HR_max was computed for all patients using the 220 - age equation and two disease-specific equations, with the predicted values used to calculate THR via the straight percent and HR_reserve methods. The THR was also computed using resting heart rate (HR) +20 and +30 bpm.

Results: Mean predicted HR_max using the 220 - age equation (161 +/- 11 bpm) and the disease-specific equations (123 +/- 9 bpm) differed (P < .001) from measured HR_max (133 +/- 21 bpm). Also, THR computed using predicted HR_max resulted in values that were infrequently within the guideline-based HR_reserve range calculated using measured HR_max. Specifically, 0 to <=61% of patients would have had an exercise training HR that fell within the guideline-based range of 50-80% of measured HR_reserve. Use of standing resting HR +20 or +30 bpm would have resulted in 100% and 48%, respectively, of patients exercising below 50% of HR_reserve.

Conclusions: A THR computed using either predicted HR_max or resting HR +20 or +30 bpm seldom results in a prescribed exercise intensity that is consistent with guideline recommendations for patients in CR.