RESUMEN
BACKGROUND: Exercise fear and low exercise self-efficacy are common in patients attending cardiac rehabilitation (CR). This study tested whether exercise prescription methods influence exercise fear and exercise self-efficacy. We hypothesized that the use of graded exercise testing (GXT) with a target heart rate range exercise prescription, relative to standard exercise prescription using rating of perceived exertion (RPE), would produce greater reductions in exercise fear and increase self-efficacy during CR. METHOD: Patients in CR (N = 32) were randomized to an exercise prescription using either RPE or a target heart rate range. Exercise fear and self-efficacy were assessed with questionnaires at three time points: baseline; after the GXT in target heart rate range group; and at session 6 for the RPE group and CR completion. Items were scored on a five-point Likert-type scale with higher mean scores reflecting higher fear of exercise and higher self-efficacy. To analyze mean differences, a mixed effects analysis was run. RESULTS: There were no significant changes in exercise self-efficacy between baseline and discharge from CR; these were not statistically significant (mean differences baseline - 0.63; end - 0.27 (p = 0.13)). Similarly, there was no change in fear between groups (baseline 0.30; end 0.51 (p = 0.37)). CONCLUSION: Patients in the RPE and target heart rate groups had non-significant changes in exercise self-efficacy over the course of CR. Contrary to our hypothesis, the use of GXT and target heart rate range did not reduce fear, and we noted sustained or increases in fear of exercise among patients with elevated baseline fear. A more targeted psychological intervention seems warranted to reduce exercise fear and self-efficacy in CR.
RESUMEN
PURPOSE: Although ratings of perceived exertion (RPE) are widely used to guide exercise intensity in cardiac rehabilitation (CR), it is unclear whether target heart rate ranges (THRRs) can be implemented in CR programs that predominantly use RPE and what impact this has on changes in exercise capacity. METHODS: We conducted a three-group pilot randomized control trial (#NCT03925493) comparing RPE of 3-4 on the 10-point modified Borg scale, 60-80% of heart rate reserve (HRR) with heart rate (HR) monitored by telemetry, or 60-80% of HRR with a personal HR monitor (HRM) for high-fidelity adherence to THRR. Primary outcomes were protocol fidelity and feasibility. Secondary outcomes included exercise HR, RPE, and changes in functional exercise capacity. RESULTS: Of 48 participants randomized, four patients dropped out, 20 stopped prematurely (COVID-19 pandemic), and 24 completed the protocol. Adherence to THRR was high regardless of HRM, and patients attended a median (IQR) of 33 (23, 36) sessions with no difference between groups. After randomization, HR increased by 1 ± 6, 6 ± 5, and 10 ± 9 bpm ( P = .02); RPE (average score 3.0 ± 0.05) was unchanged, and functional exercise capacity increased by 1.0 ± 1.0, 1.9 ± 1.5, 2.0 ± 1.3 workload METs (effect size between groups, ηp2 = 0.11, P = .20) for the RPE, THRR, and THRR + HRM groups, respectively. CONCLUSIONS: We successfully implemented THRR in an all-RPE CR program without needing an HRM. Patients randomized to THRR had higher exercise HR but similar RPE ratings. The THRR may be preferable to RPE in CR populations for cardiorespiratory fitness gains, but this needs confirmation in an adequately powered trial.