Ratings of Perceived Exertion at the Ventilatory Anaerobic Threshold in People with Coronary Heart Disease: A CARE CR study

Background: Exercise prescription guidelines for patients undertaking cardiovascular rehabilitation (CR) are based on heart rate training zones and ratings of perceived exertion (RPE). In the UK, guidelines indicate that patients should exercise at an exercise intensity between RPE 11 to 14. Objectives: We aimed to determine the accuracy of this approach by comparing this RPE range with an objectively measured marker of exercise intensity, the ventilatory anaerobic threshold (VAT), and examine whether baseline directly-determined cardiorespiratory fitness (CRF) influences the association between VAT and RPE. Methods: A maximal cardiopulmonary exercise test was conducted prior to an 8-week community-based CR programme. Peak oxygen uptake (V̇O2peak) and the VAT were recorded and the RPE at the workload in which VAT was identified was recorded. Data were then split in to tertiles, based on V̇O2peak, to determine if RPE at the VAT was different in patients with low, moderate or higher CRF. Results: Seventy patients [age 63.1 (10.0) years; BMI 29.4 (4.0) kg·m−2; 86% male] were recruited. At baseline, the mean RPE at the VAT (RPE@VAT) was 11.8 (95% CI: 11-12.6). The RPE@VAT was significantly different in low and higher CRF groups (P<0.001). The mean RPE@VAT was 10.1 (8.7-11.5), 11.8 (10.5-13.0), and 13.7 (12.5-14.9) for the low, moderate and higher CRF groups, respectively. Conclusions: When using RPE to guide exercise intensity in CR populations, it is important to consider the influence of baseline CRF. Mean RPEs of ~10, 12 and 14 correspond to the VAT in low, moderate and higher fit patients, respectively.