The feasibility of implementing high-intensity interval training in cardiac rehabilitation settings: a retrospective analysis

151 patients with cardiovascular disease (CVD) or CVD risk factors referred to an on-site cardiac rehabilitation program, mean age 57.4, 67% male, based in Canada (University of Ottawa Heart Institute). Key inclusion: baseline exercise level ≥4 METS, able to sustain at least 30 min of aerobic exercise, no contraindications for high-intensity exercise, and able to independently self-monitor.

High-intensity interval training (HIIT) consisting of a 10-min warm-up (60-70% HRpeak), 4 x 4-min high-intensity intervals (85-95% HRpeak) interspersed with 3-min lower intensity intervals (60-70% HRpeak), and a 10-min cool-down. Administered twice weekly for 10 weeks.

Feasibility of HIIT in a cardiac rehabilitation setting, assessed by exercise attendance, compliance to prescribed heart rate ranges, patient experience (perceived effort, difficulty, satisfaction), and safety.