"Don't just sit there - do something!" The measurement of sedentary behavior

In 1954, Jeremy Morris published one of many landmark studies, based on the health records of 25,000 London Transport workers (Morris & Raffle, 1954). In this report, the incidence of coronary heart disease was lower in double-decker bus conductors, who walked up and down the stairs of the bus collecting fares all day, compared to drivers, who sat in the driving seat all day. Conductors were also less likely than drivers to subsequently die, as measured over follow-up periods of 0 to 3 days, 4 days to 3 months, and 4 months to 3 years after the initial episode. In the years since Morris’s now-famous “London Bus Study,” this evidence has been cited several thousand times and is usually described as exercise epidemiology or physical activity epidemiology. More recently, scientists have come to recognize the study as also comprising sedentary epidemiology. In other words, Morris and Raffle’s evidence reflects not only the health benefits associated with regular physical activity, but also the health risks associated with prolonged sitting.