Greater Improvement in Cardiorespiratory Fitness Using Higher-Intensity Interval Training in the Standard Cardiac Rehabilitation Setting

In Brief PURPOSE: We tested the hypothesis that higher-intensity interval training (HIIT) could be deployed into a standard cardiac rehabilitation (CR) setting and would result in a greater increase in cardiorespiratory fitness (ie, peak oxygen uptake, ) versus moderate-intensity continuous training (MCT). METHODS: Thirty-nine patients participating in a standard phase 2 CR program were randomized to HIIT or MCT; 15 patients and 13 patients in the HIIT and MCT groups, respectively, completed CR and baseline and followup cardiopulmonary exercise testing. RESULTS: No patients in either study group experienced an event that required hospitalization during or within 3 hours after exercise. The changes in resting heart rate and blood pressure at followup testing were similar for both HIIT and MCT. at ventilatory-derived anaerobic threshold increased more (P < .05) with HIIT (3.0 ± 2.8 mL·kg·−1min−1) versus MCT (0.7 ± 2.2 mL·kg·−1min−1). During followup testing, submaximal heart rate at the end of stage 2 of the exercise test was significantly lower within both the HIIT and MCT groups, with no difference noted between groups. Peak V˙o2 improved more after CR in patients in HIIT versus MCT (3.6 ± 3.1 mL·kg.−1·min−1 vs 1.7 ± 1.7 mL·kg.−1·min−1; P < .05). CONCLUSIONS: Among patients with stable coronary heart disease on evidence-based therapy, HIIT was successfully integrated into a standard CR setting and, when compared to MCT, resulted in greater improvement in peak exercise capacity and submaximal endurance. Compared with patients in a standard phase 2 cardiac rehabilitation program undergoing moderate-intensity continuous training, patients undergoing higher-intensity interval training experienced a >2-fold increase in peak exercise capacity (peak oxygen uptake) and a >4-fold increase in submaximal endurance (oxygen uptake at ventilatoryderived anaerobic threshold).