Occupational Physical Activity Tied To Major Adverse Cardiovascular Events, Mortality

Although leisure time physical activity is associated with a lower risk of all-cause mortality and major adverse cardiovascular events (MACE), the risk of both increases with higher levels of occupational physical activity, a new study suggests.

Researchers examined data on 104,046 adults who participated in the Copenhagen General Population Study with baseline assessments conducted from 2003 to 2014, and a median follow-up period of 10 years. During the study period, researchers identified 7,913 (7.6%) instances of MACE and 9,846 (9.5%) fatalities from all causes.

​

Compared to participants with the lowest levels of physical activity at work, people were significantly more likely to experience MACE when they had moderate (HR 1.04), high (HR 1.15), and very high (HR 1.35) occupational physical activity levels. Similarly, the risk of all-cause mortality was greater with moderate (HR 1.06), high (HR 1.13), and very high (HR 1.27) occupational physical activity levels.

In contrast, compared to participants with the lowest levels of leisure time physical activity, people were significantly less likely to experience MACE when they had moderate (hazard ratio 0.86), high (HR 0.77) or very high (HR 0.85) leisure time physical activity levels. The risk of all-cause mortality was also lower with moderate (HR 0.74), high (HR 0.59), and very high (HR 0.60) leisure time physical activity levels.

"While leisure physical activity leads to improved fitness, health and wellbeing, work physical activity may lead to fatigue, no fitness gain, and elevated heart rate and blood pressure over the day without sufficient rest," said lead study author Andreas Holtermann of the National Research Centre for the Working Environment in Copenhagen, Denmark.

"Clinicians should be aware that adults with high physical activity levels at work do not get fit or in better health from their work activities," Holtermann said by email. "Actually, it seems to be the opposite."

It's possible that workers with physically demanding jobs might benefit from getting more leisure time physical activity, but it's also likely that they may be too fatigued from strenuous labor to get sufficient exercise outside of the workplace, Holtermann said.

For this reason, employers may need to consider how to allow workers with physically demanding jobs to get sufficient variation in their activities, periods of intense exercise, and periods of rest throughout the day to achieve health benefits similar to those seen with leisure time exercise, Holtermann added.

The analyses were multivariable adjusted for lifestyle, health, living conditions, and socioeconomic factors. In addition, sensitivity analyses "with adjustments for a long list of confounding factors" did not change the main finding, the authors note in the European Heart Journal.

One limitation of the study is that both occupational and leisure time physical activity were self-reported, not objectively measured. The study sample was from the general population of Whites of Danish descent from the greater Copenhagen area, including both high- and low-income areas, and might thus not be generalizable to all other countries in Europe and elsewhere, the authors add.

While physical activity overall can be cardioprotective, the study results highlight the potential for the context of exercise to influence whether it's beneficial, said Martin Halle of the department of prevention and sports medicine at the University Hospital Klinikum in Munich, Germany, who coauthored an editorial accompanying the study.

Occupational "physical activity is different in the way that it is accompanied by environmental factors such as night shifts, stress, repetitive strain, and low recovery between exercise bouts," Halle said by email. "This seems to do more harm than the protective effects of exercise."

—Lisa Rapaport

Source