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Exercise helps the heart, but can manual labor hurt?


May 12, 2021 – Not all exercise is created equal and exercise you do in your leisure time is better for your heart health than exercise at work. In fact, physical exercise at work can actually be harmful to heart health, according to a study published in April.

The difference between leisure time and workplace exercise is sometimes referred to as the “physical activity paradox,” says lead study author Andreas Holtermann, PhD, of the National Center for working environment research in Copenhagen, Denmark, explains WebMD.

“Our results suggest that clinicians, patients and managers should be aware that having manual work requiring physical activity may not improve the fitness and health of workers, while recreational physical activity improves health. should be encouraged, ”he said.

Do the exercise guidelines apply to everyone?

According to the World Health Organization and the US Department of Health and Human Services, physical activity is essential for maintaining and improving health, but these guidelines do not distinguish between recreational physical activity and of work. But some research suggests that the physical activity required at work may not offer the same benefits and may even increase heart risk.

These previous studies were not strong enough to offer definitive conclusions. Additionally, “much of the existing evidence on physical activity and health comes primarily from recreational physical activity among more educated white-collar populations,” says Holtermann. The question is whether they apply to on-the-job exercise in other groups.

To focus on the differences between manual labor and recreational exercise, Holtermann and his team used data from 104,046 adults (between 20 and 100 years old) who participated in the Copenhagen general population study of 2003 to 2014. Participants came from the greater Copenhagen region, which included high and low income regions.

The participants themselves self-declared their leisure and professional physical activity, demographics, lifestyle, medical information and living conditions. They also had a physical exam which included height, weight, resting blood pressure, and heart rate. The 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 cardiac events, such as fatal or non-fatal heart attacks or strokes (7.6 % some participants).

High levels of leisure time activities were associated with a lower risk of cardiac events and a lower risk of death. But a lot of physical activity at work was linked to a higher risk of heart attacks and strokes, and a higher risk of death.

Holtermann says the results may seem “surprising”, in light of the World Health Organization’s recommendation that “all steps count for better health.”

However, he has had “many years of experience” in measuring the physical activity demands placed on manual workers and has “a long experience of discussing this subject with employees and managers, unions, venues. work and decision makers ”.

For people working in these settings, “it is nothing new that the health effects of physical activity at work differ.” But many “don’t see the guidelines as for them, but for more educated white-collar workers,” he says.

He highlighted other differences between professional and leisure activities.

“I think the main important difference is the huge difference in dose – often 6-8 hours of physical activity at work over consecutive days, versus 30-60 minutes at leisure on some days a week,” he says.

Controversial conclusions

An accompanying editorial by Martin Halle, MD, and Melanie Heitkamp, ​​PhD, both of the Technical University of Munich in Germany, disputes the study results.

“Evidence from many populations and continents has widely and consistently shown that regular physical activity has beneficial effects on cardiovascular health and premature mortality, a scientific finding that has been widely implemented in the guidelines of the WHO. [World Health Organization] as well as the European Society of Cardiology, ”they write.

The editorial nevertheless suggests some possible explanations for the “physical activity paradox” in the present study. Leisure exercise can often be more aerobic, while professional exercise can involve “repetitive resistance exercise for short periods of time and often insufficient recovery time.”

In addition, “workers in heavy manual jobs may be particularly exposed to psychological factors (eg night shifts and environmental stressors such as noise or air pollution)”, speculate- they.

Interpret with caution

Genevieve Dunton, PhD, professor in the departments of preventive medicine and psychology at the University of Southern California, also expressed reservations about the implications of the study, saying the results “should be interpreted with caution.”

While there is “certainly a plausible argument that occupational physical activity offers fewer cardiovascular benefits than recreational physical activity … the data may not support to go so far as to state that the Professional physical activity in itself is detrimental to cardiovascular health, ”she said.

The study omits two factors that could “explain the observed association” and were not taken into account by the researchers, she says: emotional responses during physical activity and overall psychological stress.

“Individuals may experience more positive emotional responses… during leisure time compared to professional physical activity, which could lead to more mental health benefits and lower risk of cardiovascular events / mortality,” she says. .

Plus, she says, those who work by hand experience more psychological stress than those who have the time and resources to exercise in their spare time.

Without taking this emotional stress into account, “we have to be very hesitant to say that professional physical activity increases the risk of cardiovascular events and death,” says Dunton.

Triple burden

Commenting on the study for WebMD, Andrew Freeman, MD, co-chair of the American College of Cardiology Nutrition and Lifestyle Working Group, states that while physical activity – including exercise at work – Generally helpful, “Dedicated physical activity is good for your heart, mind and body, and that’s probably the most important point this study captures.

Exercise in the workplace is often stressful and also associated with work-related responsibilities. “Exercising for a dedicated period – ‘that’s for me” – and especially being outside in nature, where many people walk or jog, is good for cardiovascular health, “he says. he.

Holtermann agrees, noting that physical activity at work is controlled by work output, while recreational exercise is tailored to personal needs, motivation and context, he says.

“People with unhealthy manual labor are also those with fewer resources and possibilities, which is a triple burden that can play an important role in explaining the socio-economic gap in health”, he said.

WebMD Health News

Sources

Andreas Holtermann, PhD, National Center for Research on the Work Environment, Copenhagen, Denmark.

World Health Organization: “WHO Guidelines on Physical Activity and Sedentary Behavior”.

Andrew Freeman, MD, co-chair, Nutrition and Lifestyle Working Group, American College of Cardiology.

Genevieve Dunton, PhD, Professor, Departments of Preventive Medicine and Psychology, University of Southern California.

JAMA: “The Physical Activity Guidelines for Americans.”

European Heart Journal: “The paradox of physical activity in cardiovascular disease and all-cause mortality: the contemporary Copenhagen study of the general population of 104,046 adults”, “Prevention of cardiovascular disease:” every step counts “applies he at professional work? “


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