Exercise in the prevention of coronary heart disease.

Epidemiological studies have left no doubt as to the existence of a strong inverse relationship between physical exercise and coronary heart disease (CHD) risk. British studies of transport workers and civil servants, together with American studies of stevedores and college alumni, have provided persuasive evidence that contemporary vigorous activity is accompanied by lower risk of both fatal and nonfatal CHD. The relationship is largely independent of influential characteristics of high risk such as cigarette smoking, hypertension, obesity, and family history of hypertensive--atherosclerotic disease. Recent studies of occupational or leisure physical exercise among residents of Framingham, Massachusetts, the state of Iowa, four residential areas of Holland, urban--rural sections of Puerto Rico, Seattle--King County, Washington, city employees in Los Angeles, and various regions of Finland and Norway support the likelihood that the inverse relationship of exercise and CHD is causal, signifying a protective effect of exercise rather than an incidental contrast due to a selective influence of precursive CHD symptoms. Experimental studies in monkeys have added laboratory evidence that endurance exercise inhibits the development of CHD. The questions we need to address are not whether exercise is a real element for cardiovascular health, but what kind of exercise is needed, and how much, i.e., with what frequency, intensity, timing, and duration. An understanding of the ways and means by which exercise alters CHD risk is only beginning to emerge, but there is wide acceptance that its benefits are vitally needed in the sedentary Western world.