The Effect and Safety of Aerobic Interval Training According to Exercise Intensity in Acute Coronary Syndrome

To evaluate the effect of increasing the maximal oxygen uptake ((Equation is included in full-text article.)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 (Equation is included in full-text article.)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, (Equation is included in full-text article.)O2max was significantly increased in both groups. However, the increment of (Equation is included in full-text article.)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 (Equation is included in full-text article.)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.