Vigorous exercise in leisure-time: protection against coronary heart disease.

1138 first clinical episodes of coronary heart disease (CHD) in 17 944 middle-aged male office workers in the Civil Service are reported. Men who engaged in vigorous sports, keep-fit, and the like during an initial survey in 1968-70 had an incidence of CHD in the next 8 1/2 years somewhat less than half that of their colleagues who recorded no vigorous exercise. The CHD rates of men who took such vigorous exercise were lower in both fatal and non-fatal clinical manifestations, though more so in fatal; throughout the age-range studied, though more striking in later middle age and early old age; and in all other sub-groups examined, including men with a family history of CHD, the obese, the short of stature, cigarette smokers, and men with severe hypertension and subclinical angina, as well as in those in favourable situations for CHD or neutral. The generality of the advantage suggests that vigorous exercise is a natural defence of the body, with a protective effect on the ageing heart against ischaemia and its consequences.