Is the risk in active jobs or other social factors?
A study of transport workers in the 50s found conductors were healthier than the more sedentary drivers.
Flickr: Paul Townsend
Landmark research in the 1950s looked at the difference between London Transport Authority conductors, whose jobs kept them active, and drivers, whose jobs kept them relatively sedentary. The drivers were found to be at higher risk of coronary heart disease.
Since the 1950s, many physically strenuous jobs have been made superfluous by technological advances, suggested Professor Jo Salmon from Deakin University’s Institute for Physical Activity and Nutrition, who was not involved in the study.
“Times have changed and we know there’s not that many highly active occupations left,” she said.
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“While some of the studies adjusted for things that we call confounders — like smoking, alcohol intake, dietary intake, which are all independent risk factors for premature death — we do know that people who are living in disadvantage are more likely to have these clustered risk behaviours. This is all bundled up together,” Professor Salmon said.
Curtin University’s Professor Leon Straker, who co-authored the paper, agreed socioeconomic status was difficult to extricate from the physical nature of the jobs in the study, and added that these jobs often had additional risk factors, such as chemical exposure or increased sun exposure.
But he thinks the link is still there.
Some of the studies that were analysed as part of the research published today tried to control for socioeconomic status.
“Our hypothesis is that the physical activity that people do in work is different to the physical activity people do in leisure, and it’s different in ways that’s really important for how a body responds and becomes fitter, stronger and healthier,” he said.
“If you think about a lot of physically active jobs, they’re often active for really long periods of time, eight hours as a typical workday or longer, and the intensity that they’re working at isn’t necessarily as high as somebody who is going out for a 30-minute run.
“So the intensity’s lower, but it’s over a much longer period of time and you don’t have the same recovery options at work as you do in leisure.”
Professor Straker speculated it could be something about the difference in intensity or the repetitive movements of occupational exercise that might mean men don’t get the same health benefits as they do from leisure activity.
The study’s link between higher physically demanding jobs and risk of death was only found in men, not women — who got the same benefit from workplace physical activity as they’d get from leisure activity.
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“Our best guess is that it’s probably a combination of the two.”
But she said workers with physical jobs who took the time to exercise too, would likely be fitter and better able to cope with the demands of the job — as well as having the longer-term benefit of reducing the risk of premature death.
“Because probably, what will happen is you will manage your job easier and find the job less stressful.”