Feasibility, Safety, Adherence and Efficacy of High-Intensity Interval Training Cardiac Rehabilitation Programs for Patients with Coronary Heart Disease

Abstract

There are reservations regarding the clinical application of high-intensity interval training (HIIT) in real-world cardiac rehabilitation settings. This study investigated HIIT compared with moderate-intensity continuous training (MICT) within a standard hospital cardiac rehabilitation program. Two hundred and sixty adults with angiographically proven coronary artery disease undergoing a standard 4-week cardiac rehabilitation program were approached. Ninety-three patients were subsequently randomised to: 1) HIIT (n = 46): 4 x 4-minute high-intensity intervals at 15–18 rating of perceived exertion (RPE, range 6–20) interspersed with 3-minute active recovery periods; or 2) MICT (n = 47): usual-care exercise involving 40-minutes of aerobic exercise at 11–13 RPE. Participants completed two supervised sessions and one home-based session per week. Feasibility was assessed using staff and participant questionnaires. The incidence and seriousness of adverse events were recorded to evaluate safety. Adherence to the exercise protocol was assessed from exercise records and self-report logs. Average training RPE was significantly higher for HIIT (16 ± 1 vs 12 ± 1) and resulted in a significant improvement in peak oxygen uptake compared to MICT (+2.9 ± 3.5 vs +1.1 ± 0.0 mL/kg/minute, p = 0.012). There was no difference in the incidence of serious adverse events between HIIT (n = 2) and MICT (n = 2). Adherence to the exercise protocol was high in both groups (HIIT 80% vs MICT 87%). Feasibility scores were equal between groups (98%) regarding desire to continue their randomised training. Staff acceptance of the HIIT program was high. Compared to usual care (MICT), HIIT was safe, feasible, and more efficacious for improving fitness without loss of exercise adherence.