What is physical labor

Does physical work endanger the heart?

Copenhagen. Those who exercise a lot keep their cardiovascular system fit and healthy. According to a recent study from Denmark, however, this only applies to physical activity in leisure time, not at work (European Heart Journal 2021; 42 (15): 1499–1511). The occupational physician Andreas Holtermann from the National Research Center for the Working Environment in Copenhagen and his colleagues investigated the importance of physical work for heart health in over 104,000 women and men from the Copenhagen General Population Study.

Information on exercise intensity

The participants were included in the study between 2003 and 2014 and followed up for a median of ten years. In addition to socio-economic parameters and lifestyle factors, health parameters such as BMI, blood pressure, blood pressure medication, resting heart rate as well as LDL, HDL, triglyceride and blood sugar values ​​were recorded and taken into account in the evaluation. In addition, COPD was either excluded or documented according to the four GOLD stages.

The test subjects were divided into four groups (low, moderate, high, very high) based on the information on exercise intensity in their free time. A similar procedure was followed with regard to work-related physical demands.

The results: 7913 major cardiovascular events (MACE) and 9846 deaths had occurred during the observation period. It was noticeable that more men than women did intensive sport in their free time. Age, on the other hand, played a subordinate role.

As expected, there were more smokers and more overweight people in the group with little leisure time activity. In addition, the proportion of people with a short training period, lower income, unhealthy eating style, COPD GOLD stage 4 and / or diabetes was highest in this group.

Hardly physically working subjects were more likely to smoke and were overweight compared to those who worked sitting down. They also had a lower level of schooling, a less healthy diet and drank more alcohol than participants with less physically demanding jobs.

Movement is not always movement

But even when all of these influencing factors are taken into account, the picture for the health effects of physical activity in leisure and at work is contradictory. Exercise in leisure time had a consistently positive effect: Compared with the group with the least physical activity, subjects who did moderate sport in leisure time had a 14 percent lower risk of MACE. At high intensity it fell by 23 percent, at very high intensity by 15 percent. The mortality risk was 26 percent, 41 percent and 40 percent lower, respectively.

The situation is different for job-related physical activity: Compared to the participants who stated that they mainly work while sitting, the MACE risk increased by 4 percent for moderately physically strenuous work, by 15 percent for high intensity and by 35 percent for very high intensity. The mortality risk, in turn, increased by 6 percent, 13 percent and 27 percent, respectively.

Paradoxical effect in leisure and at work

The Danish scientists explain the paradoxical effect of physical activity in leisure and at work with the different characteristics of physical exertion. While exercise in leisure time is usually dynamic and carried out with high intensity over a shorter period of time, the intensity of physical stress at work is less, but the performance must be performed over a much longer period of time. In addition, the movement sequences are rather static and sometimes unnatural.

At the same time, the scientists emphasize that the negative health effects of intensive physical work cannot be offset by recreational sport. "Neither for the MACE nor for the mortality risk was there an interaction between the effects of physical work and recreational sport."