To evaluate the effect of increasing the maximal oxygen uptake (o2max) and the safety of maximal-intensity aerobic interval training (MAIT) compared with high-intensity aerobic interval training (HAIT).
Forty-seven patients with first-ever acute coronary syndrome were assigned to MAIT or HAIT. Subjects underwent adaptation period during the first 2 wk of cardiac rehabilitation and then MAIT at 95-100% of the heart rate reserve or HAIT at 85% of the heart rate reserve, 3 d/wk for 4 wk. The primary outcome was o2max. The secondary outcomes were major cardiovascular complications, hemodynamic responses, myocardial oxygen demand, cardiometabolic health, and echocardiographic findings.
A total of 670.5 hr of MAIT and HAIT were completed. After 6 wk of aerobic interval training, o2max was significantly increased in both groups. However, the increment of o2max was significantly greater in the MAIT group than in the HAIT group (P < .05). The percentage increases for MAIT and HAIT were 31% and 17%, respectively. No major cardiovascular or musculoskeletal complications were noted.
The results of this study indicate that 6 wk of MAIT resulted in statistically significantly better improvement in o2max than 6 wk of HAIT at a similar total work in patients with acute coronary syndrome. Moreover, both MAIT and HAIT may be safe to use in the cardiac rehabilitation setting.