Demanding physical work associated with an increased risk of cardiovascular disease

http://www.eurekalert.org/pub_releases/2013-04/esoc-dpw041613.php

Public release date: 18-Apr-2013
Contact: Jacqueline Partarrieu
European Society of Cardiology

Two studies presented at this year's EuroPRevent 2013 congress suggest that demanding physical work has a detrimental effect on an individual's risk of coronary heart disease.

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After adjusting for various potential confounding factors such as age, sex, body mass index, smoking, hypertension, hypercholesterolemia, diabetes, family history of cardiovascular disease and adherence to the Mediterranean diet, results confirmed that those occupied in progressively less physically demanding jobs (that is, for each unit increase of the scale) were associated with a 20% lower likelihood of acute coronary events (a statistically significant odds ratio of 0.81%) or of ischaemic stroke (odds ratio 0.83%).

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Within the context of exercise recommendations, he noted that the somewhat paradoxical results could possibly be attributed to the stress experienced by people with physically demanding jobs. Stress, he added, may be one reason why hard physical work may not be comparable to the physical exercise recommended for health and well-being, which tend to be non-stressful behaviours. In addition, he explained, such work is often not well paid, which may restrict access to the healthcare system.

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Results during follow-up showed an overall beneficial effect of leisure time physical activity, but an adverse effect of demanding physical work. However, Dr Els Clays, from the Department of Public Health at the University of Ghent, Belgium, added that an "interaction effect" was also evident in the results: while moderate-to-high physical activity during leisure time was associated with a 60% reduced risk of coronary events in men with low occupational physical activity (a statistically significant hazard rate of 0.40), this protective effect was not observed in those workers who were also exposed to high physical work demands (HR 1.67).

Dr Clays added that, after adjusting for socio-demographic and well established coronary risk factors, men with high physical job demands were more than four times likely to have coronary heart disease when they also engaged in physical activity during leisure time (HR 4.77).

Commenting on the results Dr Clays said: "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. 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.