May 12, 2021 — All exercise is not created equal, and the exercise you get during leisure time is better for your heart health than on-the-job exercise. In fact, on-the-job physical exercise may actually be harmful to heart health, according to a study published in April.

The difference in leisure-time exercise and workplace exercise is a phenomenon sometimes called the “physical activity paradox,” lead study author Andreas Holtermann, PhD, of the National Research Center for the Working Environment in Copenhagen, Denmark, tells WebMD.

“Our findings suggest that clinicians, patients, and managers ought to be aware that having a manual physical activity-demanding job might not improve fitness and health of the workers, while health-enhancing leisure-time physical activity ought to be promoted,” he says.

Do Exercise Guidelines Apply to Everyone?

According to the World Health Organization and the U.S. Department of Health and Human Services, physical activity is essential to maintain and improve health, but these guidelines do not distinguish between leisure- and work-time physical activity. But some research has suggested that physical activity required at work may not provide the same benefits and may even increase heart risk.

These previous studies weren’t robust enough to offer definite conclusions. Also, “much of the existing evidence on physical activity and health is predominantly from leisure-time physical activity among higher-educated white-collar populations,” Holtermann says. The question is whether they apply to on-the-job exercise in other groups.

To home in on the differences between manual labor and leisure-time exercise, Holtermann and his team used data from 104,046 adults (between 20 and 100 years old) who took part in the Copenhagen General Population Study from 2003 to 2014. Participants came from the greater Copenhagen area, which included high- and low-income regions.

Participants self-reported their leisure and occupational physical activity, demographic, lifestyle, medical information, and living conditions. They also had a physical exam that included height, weight, resting blood pressure, and heart rate. Participants were then followed for an average of 10 years.

Quantity vs. Quality

During the follow-up period, there were 9,846 deaths from all causes (9.5% of participants) and 7,913 major heart events, such as fatal or nonfatal heart attacks or strokes (7.6% of participants).

High levels of leisure-time activity were associated with a lower risk of heart events and a lower risk of death. But lots of physical activity at work was linked to more chances of heart attacks and strokes and a higher risk of death.

Holtermann says the findings might seem “surprising,” in light of the recommendation from the World Health Organization that “all steps count toward better health.”

However, he has had “many years of experience” measuring physical activity demands placed upon manual laborers and has “long experience discussing this topic with employees and managers, unions, workplaces, and policymakers.”

To people working in these settings, “it is nothing new that the health effects of physical activity in work differ.” But many do not “consider