Low-Volume, High-Intensity Interval Training in Patients with CAD

TLDR

Interval exercise training improves physiological indices in CAD patients, but the effectiveness of low‑volume high‑intensity interval training (HIT) in cardiac rehabilitation has not been established. The study compared 12‑week HIT with higher‑volume moderate‑intensity endurance exercise on brachial artery flow‑mediated dilation and cardiorespiratory fitness in patients with coronary artery disease. Twenty‑two CAD patients were randomized to HIT or END and completed two supervised sessions per week for 12 weeks, with END performing 30‑50 min of continuous cycling at 58 % peak power output and HIT performing ten 1‑min intervals at 89 % PPO interspersed with 1‑min rest at 10 % PPO. Both HIT and END produced significant improvements in flow‑mediated dilation and VO₂ peak, with no differences between groups, indicating that low‑volume HIT is an effective alternative to longer moderate‑intensity exercise.

Abstract

Isocaloric interval exercise training programs have been shown to elicit improvements in numerous physiological indices in patients with CAD. Low-volume high-intensity interval exercise training (HIT) is effective in healthy populations; however, its effectiveness in cardiac rehabilitation has not been established. This study compared the effects of 12-wk of HIT and higher-volume moderate-intensity endurance exercise (END) on brachial artery flow-mediated dilation (FMD) and cardiorespiratory fitness (VO2 peak) in patients with CAD.Twenty-two patients with documented CAD were randomized into HIT (n = 11) or END (n = 11) based on pretraining FMD. Both groups attended two supervised sessions per week for 12 wk. END performed 30-50 min of continuous cycling at 58% peak power output (PPO), whereas HIT performed ten 1-min intervals at 89% PPO separated by 1-min intervals at 10% PPO per session.Relative FMD was increased posttraining (END, 4.4% ± 2.6% vs 5.9% ± 3.6%; HIT, 4.6% ± 3.6% vs 6.1% ± 3.4%, P ≤ 0.001 pre- vs posttraining) with no differences between groups. A training effect was also observed for relative VO2 peak (END, 18.7 ± 5.7 vs 22.3 ± 6.1 mL · kg(-1) · min(-1); HIT, 19.8 ± 3.7 vs 24.5 ± 4.5 mL · kg(-1) · min(-1), P < 0.001 for pre- vs posttraining), with no group differences.Low-volume HIT provides an alternative to the current, more time-intensive prescription for cardiac rehabilitation. HIT elicited similar improvements in fitness and FMD as END, despite differences in exercise duration and intensity.