Death Rates Among Physically Active and Sedentary Employees of the Railroad Industry

Abstract

Studies have indicated that men in sedentary occupations are more liable to have coronary heart disease than those in occupations requiring moderate to heavy physical activity. To test this hypothesis a study was conducted of the death rates among clerks, switchmen, and section men employed in the railroad industry. MORRIS, et al.,1 demonstrated an association between the physical activity required by an occupation and the incidence of coronary heart disease over a period of two years among bus drivers and conductors employed by the London Transport Executive. Additional studies of postmen on the one hand, and telegraphers, telephonists, clerks, and supervisory personnel of the postal service on the other, also indicated a higher incidence of coronary heart disease among men in the more sedentary jobs than among men in the occupations requiring greater physical activity. In addition, it was found that men in sedentary occupations had less angina pectoris and a higher death rate during the first three months after an initial coronary attack than men in the more active occupations. Since that time, results of other studies in Great Britain2-5 and in the United States67 have supported the thesis proposed by Morris that men in physically active jobs have a lower incidence of coronary (ischemic)

Ten-year mortality from coronary heart disease among 172,000 men classified by occupational physical activity.

“…Such a ratio is in line with those reported by similar studies on large cohorts, like the relative risk of 1.3-1.6 found in a survey of American railroad men (22) and the value of 1.7-1.8 for Californian longshoremen (16). In our group this ratio was substantially similar in the five-and ten-year follow-up (1.65 and 1.7, respectively), a finding suggesting that ageing and the increasing proportion of retirements do not decrease the protection of physical activity against fatal CHD in the form of MI or SD.…”

“…The role of physical activity as a coronary risk factor has been debated for a long time, and opinions have contrasted due to the difficulties of classifying single individuals as more or less active and to the confounding effects between habitual physical activity and some other risk factors, which, at least in some extensive surveys, could not be measured (1,2,3,4,6,7,8,9,10,11,12,13,14,15,16,17,18,19,21,22,24 0355-3140/79/020100-9…”

Exercise Training and Cardiac Rehabilitation in Primary and Secondary Prevention of Coronary Heart Disease

“…Many studies have documented an inverse association between job-related PA and overall CHD risk. Among these studies, Taylor et al 8 evaluated PA and CHD risk in over 190,000 US railroad workers and showed that death caused by atherosclerosis was more frequent in the relatively sedentary clerks (relative risk, 2.0) and moderately active switchmen (relative risk, 1.5) than in the section men who had high PA. Morris et al 9 studied PA in 667 male London bus drivers and conductors and determined that CHD was much lower for the more active conductors than for the drivers (age-adjusted relative risk, 1.8 risk, 1.8 for light PA and 1.7 for moderate PA vs heavy PA). However, these studies are now principally of historical interest because few jobs today require the level of PA described in these studies.…”

Occupational physical activity, energy expenditure and 11-year progression of carotid atherosclerosis

“…Research in the 1950s and 1960s, comparing different occupational groups, identified sedentary work as an important cardiovascular risk factor (76)(77)(78)(79). However, these earlier studies were vulnerable to alternative explanations because of selection bias and uncontrolled confounding.…”