Demanding Physical Work Increases Risk of Cardiovascular Disease

A new study suggests that demanding physical work has a detrimental effect on an individual's risk of coronary heart disease (CHD).

Researchers at the University of Ghent (Belgium) conducted a cohort study of more than 14,337 middle-aged men who were free of CHD at outset (1994-1998). Questionnaires were used to assess sociodemographic factors, job strain, and the level of physical activity at work and during leisure time. Classical coronary risk factors were also measured through clinical examinations and questionnaires. The incidence of coronary events was monitored during a mean follow-up time of 3.15 years to assess the association between physical activity and CHD, with adjustments for age, education, occupational class, job strain, body mass index (BMI), smoking, alcohol consumption, diabetes, blood pressure, and cholesterol.

The results showed an overall beneficial effect of leisure time occupational physical activity (OPA), but an adverse effect of demanding physical work. An interaction effect was also evident in the results, with moderate-to-high physical activity during leisure time associated with a 60% reduced risk of coronary events; this protective effect was not observed in workers who were also exposed to high physical work demands. After adjusting for sociodemographic and well established coronary risk factors, men with high physical job demands were more than four times likely to have CHD when they also engaged in OPA. The study was presented at the EuroPRevent congress, held during April 2013 in Rome (Italy).

“From a public health perspective it is very important to know whether people with physically demanding jobs should be advised to engage in leisure time activity,” said lead author and study presenter Els Clays, PhD, of the department of public health. “The results of this study suggest that additional physical activity during leisure time in those who are already physically exhausted from their daily occupation does not induce a 'training' effect but rather an overloading effect on the cardiovascular system.”

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