Health effects of physical activity.

OBJECTIVES This article examines the potential protective effect of leisure-time physical activity on the incidence of heart disease and depression. DATA SOURCE The data are from the household longitudinal component of the 1994/95 and 1996/97 cycles of the National Population Health Survey, conducted by Statistics Canada. Results are based on two subsamples: 7,158 respondents aged 20 or older who were healthy and free of heart disease in 1994/95, and 7,593 respondents aged 12 or older who were healthy and free of depression in 1994/95. ANALYTICAL TECHNIQUES Multiple logistic regression was used to estimate the effects of leisure-time physical activity on the incidence of heart disease and depression, while controlling for selected characteristics. MAIN RESULTS Individuals who were healthy and free of heart disease or depression in 1994/95 and who engaged in regular physical activity at a moderate level of energy expenditure had lower odds of reporting a diagnosis of heart disease or an episode of depression in 1996/97 than those who were less active.