Cardiorespiratory exercise intensity prescription in cardiovascular rehabilitation: do updated guideline recommendations reflect real individual effort responses?

Abstract

Aims To evaluate how accurately the updated American Heart Association and the American Association of Cardiovascular and Pulmonary Rehabilitation (AHA/AACVPR) Scientific Statement prescribes moderate-intensity exercise based on percentage of heart rate reserve (%HRR), by comparing it with heart rate (HR) at venti-latory thresholds in patients with cardiometabolic disease. Methods and results This retrospective multicentre study included 2554 individuals from 12 centres across nine countries. Heart rate at the first and second ventilatory thresholds (VT1, VT2), obtained by cardiopulmonary exercise testing (CPET), was compared with HR estimated from the guideline-defined moderate-intensity range (40-59% HRR). Agreement was assessed using the Bland-Altman analysis, calibration using the Passing-Bablok regression, and prediction error using mean absolute error. Heart rate at VT 1 closely approximated the lower limit (40% HRR), with minimal bias and a mean absolute error of 6.4 b.p.m. In contrast, HR at VT 2 was substantially higher than the upper limit (59% HRR), with a negative bias (−11.4 b.p.m.) and greater prediction error (mean absolute error of 12.0 b.p.m.). Calibration analysis showed minor deviation at VT 1 but marked systematic and proportional bias at VT 2 , indicating miscalibration at higher intensities. These findings were consistent across subgroup analyses. Conclusion The AHA/AACVPR %HRR-based recommendations accurately reflect the lower boundary of moderate-intensity exercise but underestimate the transition to higher intensities. Aligning %HRR-based prescriptions with CPET-derived physiological thresholds is likely to improve the precision and effectiveness of exercise