High-intensity Interval Training In Patients With Coronary Artery Disease: A Randomized Controlled Trial

Abstract

PURPOSE: Coronary artery disease (CAD) is the leading cause of mortality worldwide, and the prevalence is increasing. Cardiac rehabilitation is essential after a cardiac event with exercise training having a central role. Exercise training improves quality of life and reduces cardiovascular mortality and hospital admissions in CAD patients. We aimed to investigate the feasibility and efficiency of high-intensity interval training (HIIT) in patients with stable CAD. METHODS: In this randomized controlled trial, 142 patients with stable CAD and a mean age of 66.7 years completed the study, 64 in the HIIT group and 78 in the control group (CON). Patients were randomized 1:1 to supervised HIIT or standard care. HIIT was performed by training on a rowing ergometer 3 x week for 12 weeks. Patients in CON did not change their usual behavior, and all patients continued medications as prescribed before inclusion. Prior to randomization (baseline) and after 12 weeks (post-intervention), maximal oxygen consumption (VO2max), maximal pulmonary ventilation (VEmax) and maximal power output (Wmax) were determined in all patients. During the intervention period, the training load was defined as power output during training in week 3, 6 and 9. The average intensity was quantified and normalized to the average power that patients could sustain during a 5-min-all-out rowing performance test completed at week 5. RESULTS: Adherence to training was 97% (range 86-100%). Three patients dropped out because of non-fatal adverse events, and three patients reported non-severe self-limiting adverse events. The average relative power output was 72 ± 19% during warm-up and 117 ± 11 % during the interval bouts. Weekly training duration was on average 54 min. Compared to standard care, HIIT resulted in a significant (p < 0.001) greater increase in VO2max, VEmax, and Wmax (197 mL/min [160;233], 13 L/min [11;16], and 23 W [19;27]). CONCLUSIONS: Low volume HIIT performed as rowing significantly upregulated cardiorespiratory fitness (VO2max, VEmax, and Wmax) in patients with stable CAD compared to standard care. The exercise training on rowing ergometers was convenient and feasible for this frail patient group.