Cardiorespiratory fitness and quality of life at different exercise intensities after myocardial infarction.

BACKGROUND Studies relating physical exercises and health have contributed to elucidate the influence of sedentary habits on the incidence of cardiovascular diseases. OBJECTIVE To compare the effect of different intensities of aerobic exercises on patients' functional capacity (VO₂(peak)) and quality of life after acute myocardial infarction. METHODS Eighty-seven men (57.7 ± 6.1 years old) were enrolled in this prospective study and assigned to one of three groups: a) high-intensity physical training (n=29) at 85% maximum heart rate for 12 weeks; b) moderate-intensity training (n=29) at 75% maximum heart rate for 12 weeks; and c) control group (n=29), who were followed. The training groups did aerobic exercises five times a week in 45-minute sessions, besides muscular strengthening and stretching exercises. Maximum VO₂ was measured through a cardiopulmonary test, and quality of life was assessed through the MacNew Questionnaire. RESULTS Two-way ANOVA revealed a significant increase in VO₂(peak) (p<0.05) in the high-intensity training group (from 29.9 ± 2.2 ml/kg.min to 41.6± 3.9 ml/kg.min) compared with the moderate-intensity training group (from 32.0 ± 5.3 ml/kg.min to 37.1 ± 3.9 ml/kg.min). Additionally, both training groups showed a significant increase in this parameter compared with the control group (from 31.6 ± 3.9 ml/kg.min to 29.2 ±4.1 ml/kg.min). Quality of life improved significantly (p<0.05) in the high-intensity training group (from 5.66 to 6.80) and in the moderate-intensity training group (from 5.38 to 6.72), but not in the control group (from 5.30 to 5.15). CONCLUSION Exercises of greater intensity resulted in an increase in functional capacity and quality of life in patients after myocardial infarction.