Purpose: 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

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... atory fitness (V O 2peak ) in patients with CAD. Methods: 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. Results: Relative FMD was increased posttraining (END, 4.4% T 2.6% vs 5.9% T 3.6%; HIT, 4.6% T 3.6% vs 6.1% T 3.4%, P e 0.001 pre-vs posttraining) with no differences between groups. A training effect was also observed for relative V O 2peak (END, 18.7 T 5.7 vs 22.3 T 6.1 mLIkg j1 Imin j1 ; HIT, 19.8 T 3.7 vs 24.5 T 4.5 mLIkg j1 Imin j1 , P G 0.001 for pre-vs posttraining), with no group differences. Conclusions: 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.