Role of physical activity as a secondary intervention for healed myocardial infarction

Five exercise clinical trials were conducted to determine the effectiveness of physical activity on selected outcomes, especially mortality and morbidity rates, in patients recovered from myocardial infarction. Although the design of every trial differed, each evaluated the effects of medically prescribed and supervised regular physical activity. In 3 studies there were substantially lower mortality rates in the exercise patients compared with control patients, but statistically significant differences occurred in only 1 of the 3 trials. No differences between treated and control patients were observed in another trial. In the fifth trial, a slight excess mortality rate was reported for the treatment group. However, both groups in this trial were assigned to an exercise regimen in which only the frequency of attendance and intensity of regimen differed. Although regular physical activity tended to reduce mortality rates in the first 3 trials, it is apparent that it did not affect recurrence rates of nonfatal myocardial infarction. In fact, this condition generally occurred more frequently in treated than in control patients. It is clear that more clinical investigations are required before a definitive statement confirming the effectiveness of regular physical activity as a secondary intervention for myocardial infarction can be made.