Study of coronary risk factors related to physical activity in 15 171 men.

Physical activity, both at work and during leisure, was assessed in 15 171 men aged 25-74 years. Heavy leisure activity was associated with lower mean serum cholesterol levels and blood pressure. In men under 60 years the same negative association was also noted between leisure activity and relative weight and cigarette smoking. Different degrees of physical activity at work were not associated with any differences in these risk factors, nor did the level of exercise at work seem to influence the negative association between leisure activity and risk factors. Heavy leisure activity in young and middle-aged men is associated with lower levels of certain coronary risk factors and, therefore, a lower risk of coronary heart disease. The often-reported reduction in coronary morbidity and mortality with physical exercise may not be the direct effect of the exercise itself.