The place of perceived exertion ratings in exercise prescription for cardiac transplant patients before and after training

Abstract

Objective: Heart rate provides a poor guide to exercise prescription after cardiac transplantation. This study explores whether the rating of perceived exertion (RPE) provides useful alternative information.

Methods: Borg's original categoric scale was applied to 36 male patients [T, age 47(SD 9 years] as they performed a progressive cycle ergometer test an average of seven months (range two to 23 months) after cardiac transplantation. The test was repeated after 16(7) months of progressive exercise centred rehabilitation. Sedentary but healthy controls [C, n = 45, age 45(7) years] performed a similar progressive cycle test.

Results: Initially, 13 RPE units corresponded to 66(12)% of peak VO2 in T and 50(11)% in C. Rehabilitation augmented peak VO2 (by 19%) and estimated lean body mass (by 3.5%) in the cardiac transplant patients. The increase of heart rate (HR) at 13 RPE units [delta HR = 10(17) beats.min-1] showed moderate correlations with gains of lean mass (r = 0.72) and gains of peak VO2 (r = 0.58). The relative oxygen intake at 13 RPE units remained unchanged at 68(12)% of peak VO2.

Conclusions: Large inter-individual variations of RPE at a given VO2 limit the value of perceived exertion in exercise prescription. Ratings seem best restricted to fine tuning fixed distance/fixed speed exercise prescriptions in patients undergoing rehabilitation after cardiac transplantation.