Heart Rate-Perceived Exertion Relationship During Exercise in Orthotopic Heart Transplant Patients

Abstract

Exercise training in orthotopic heart transplant (OHT) patients has been shown to be beneficial. However, appropriate methods effectively guiding exercise intensity are uncertain because of the altered physiologic responses of the denervated heart. This study compares ratings of perceived exertion (RPE) and heart rate (HR) responses in 19 male OHT patients during graded exercise testing (GXT) and training and retrospectively compares two HR-based methods for determining exercise intensity with actual exercise HRs. Graded exercise tests were performed before (Tl) and after (T2) exercise training, and results were compared with exercise HRs during the first (WK-1) and last (WK-F) weeks of training. From Tl to T2, a 17.2 % mean increase in VO2max was accompanied by an 11 ± 14 min-1 increase in mean peak HR. During exercise training, RPE was maintained between 12 and 14 and treadmill work load increased 39% from WK-1 to WK-F. HR increased from 116 ± 14 beats min-1 to 126 ± 16 beats min-1. Exercise training HR usually exceeded 85 % of the peak GXT HR at Tl and T2 and occasionally exceeded 100% of the peak HR measured at Tl. The maximal HR-reserve method generally was more accurate than the straight percent of peak HR method in reflecting the actual HR achieved during exercise training. The data suggest that exercise intensity can be guided by using either RPE or, if a follow-up GXT is performed, a target heart rate range computed using the HR-reserve method.