Although the ancient Greeks counseled that a sound mind and a sound body went hand-in-hand, it wasn't until the early 1950s that the benefits of regular physical activity were carefully studied. Responding to epidemiologic data demonstrating a real increase in the incidence of heart disease after World War II, British investigators studied the differences in rates of coronary heart disease among persons in various occupations.1
See also p 2720.
The researchers looked at the incidence of myocardial infarction in more than 30 000 workers on the trams and trolleys of London. They found that sedentary drivers had a 50% greater incidence of coronary heart disease than did conductors who collected fares climbing up and down the stairs on double-deck vehicles. Not only did fewer physically active conductors have coronary heart disease, but what disease they did have was less severe and occurred at a later age.
The researchers also