On-the-job exercise keeps diseases at bay
Men’s occupational activity linked to longer life in study
Is it good for our health and longevity to heave, dig, hoist, stroll or otherwise exert ourselves during working hours? Or are strenuous occupations hard on our bodies and health?
Common sense might tell us that being in motion at work should be beneficial for our hearts and health, just as going for a jog or bike ride or working out at the gym is good for us. But some recent research has suggested that manual labor often increases workers’ risks for cardiovascular disease and premature death, meaning the effects of work-related physical activity might be different and less salubrious than those of the workouts we choose to do on our own time.
Now, though, the newest and largest study to date of occupational physical activity and mortality has some good news for those with physically demanding jobs. The new study, which involved almost half a million workers, finds that people whose jobs involve frequent moving and lifting tend to live longer than those whose occupations are deskbound. The results refute the idea that work-time exertions somehow are different from other exercise and instead suggest that, whenever possible, we should be on the move while on the job.
No one disputes that exercise is beneficial, and, in general, the more, the better. But exercise is volitional; we can decide, for the most part, whether, when, where, how long, how hard and with whom we will work out. It has not been altogether clear whether mandatory physical activity affects our bodies in the same ways as workouts we choose for ourselves.
In animal studies, it does not. When mice or rats run on treadmills, where the pace, intensity, duration and mere existence of the workouts are set for them, they typically produce stress hormones and often wind up with different biological outcomes than if they skitter through the same mileage on running wheels, something rodents voluntarily seem to love to do. In an interesting
2008 study, rats running on treadmills developed higher levels of anxiety than rats running on wheels, and showed different effects on the production of new neurons in their brains.
Some exercise scientists started to wonder a few years ago if workplace physical activity, which can be compulsory, might produce different and potentially less-desirable physiological effects on people than leisure-time exercise. To find out, they checked survey data about occupational physical activity against death registries.
According to a 2018 analysis of more than a dozen relevant studies, men whose jobs demanded frequent lifting, carrying and other tiring physical labor were 18% more likely to die prematurely than men whose jobs were less physically demanding. (The studies found no associations between women’s occupational activities and longevity.)
The review’s authors and other scientists called their findings a “physical activity paradox,” in which having to move at work seemed to undermine men’s health and life spans, while choosing to exercise during off-hours improved them.
But some exercise researchers remained skeptical. These scientists suspected that any relationship between hard labor and early death might be due more to people’s lives away from the job than to their exertions at work, and that past research had not controlled adequately for lifestyle.
So for the new study, which was published in April in The Lancet Public Health, researchers at the Norwegian School of Sport Sciences in Oslo and other institutions decided to delve as deeply and broadly as possible into lifestyle, as well as workplace labor, and life spans.
They began by turning to data already gathered by Norwegian health agencies, which, as part of ongoing studies, have been measuring the health of hundreds of thousands of Norwegians for decades. That data included detailed information about their work and exercise histories, education, income and other aspects of their lives.
The researchers pulled records for 437,378 of the participants in these studies and categorized them by job types. Some, like clerks or inspectors, did some walking and lifting at work; others performed heavy manual labor; and the rest more or less sat at their desks all day. The researchers then cross-checked people’s records against decades’ worth of databases tracking diseases and deaths in Norway.
On a first pass, their results bolstered the idea that active jobs shorten
lives. Over the course of about 30 years, men in sedentary jobs outlived those who often walked or otherwise exerted themselves at work. (As before, there were no significant links between women’s professions and their longevity.)
But when the scientists scrupulously controlled for everyone’s education, income, smoking, exercise habits and weight, the associations flipped. In this fuller analysis, men who were active at work developed heart disease and cancer at lower rates than
deskbound men. Whether they tended to walk a fair amount for work or perform other, more strenuous labor, the active men lived, on average, about a year longer.
The study shows that “every movement counts, regardless of whether you are active at work or during leisure,” said Ulf Ekelund, a professor at the Norwegian School of Sport Sciences, who oversaw the new study. Conversely, the results also remind us, he said, that sitting, even at comfortable desks or on cushy couches, is
unhealthy.
What this study does not tell us is which aspects of our lives, away from work, might most affect our health and longevity, or why women’s life spans seem generally unaffected by work-time exertions. Ekelund and his colleagues hope to look into some of those issues in future research.
But for now, he said, assume “that all physical activity is beneficial, regardless of whether it’s performed during leisure, at work, at home or during transportation.”