Occupational, leisure-time physical activity have opposing health effects
MedWire News: Results of a Danish study show that international recommendations for health-promoting physical activity need to distinguish between occupational and leisure-time physical activity.
The researchers found that leisure-time physical activity decreased the risk for long-term sickness absence (LTSA) - an acknowledged measure of global health - while occupational physical activity increased the risk.
"These findings highlight the detrimental effects of high occupational physical activity on general health," write the authors in the British Journal of Sports Medicine. They also support the beneficial effects of leisure-time physical activity on global health, they say.
"The hazard of sedentary lifestyle is widely acknowledged," explain Andreas Holtermann (National Research Centre for the Working Environment, Copenhagen) and colleagues. However, "the international recommendations for health-promoting physical activity do not distinguish between occupational and leisure-time physical activity."
The team therefore investigated whether occupational and leisure-time physical activities impose similar effects on the risk for LTSA in a representative sample of 7144 Danish employees, aged between 18 and 74 years.
Participants reported their levels of occupational and leisure-time activity in 2005, and LTSA, defined as receiving sickness absence compensation for a period of 3 or more consecutive weeks, was assessed using data from a social transfer payment register from 2005 through 2007.
Holtermann et al found that occupational physical activity increased the risk for LTSA in a dose-response manner. Specifically, workers with high levels of occupational physical activity had an 84% increased risk for LTSA compared with workers with low levels.
By contrast, increasing levels of leisure-time physical activity significantly reduced the risk for LTSA; workers with high levels of leisure-time physical activity had a 23% lower risk for LTSA compared with workers with low levels of leisure-time physical activity.
"These opposing effects of physical activity during work and leisure highlight the importance of type and setting of the physical activity for its influences on health," remark the authors.
Activity patterns characterizing occupational physical activity were heavy lifting, prolonged standing, highly repetitive work, working with the hands lifted to shoulder height or higher, and working with the back twisted or bent forward, explain the authors.
By contrast, the activity patterns characterizing the health-promoting physical activity at leisure were dynamic contractions of large muscle groups that increased whole-body metabolism and cardiac output with the ability to rest when feeling fatigued.
"Future studies ought to objectively measure characteristics of physical activity at work and leisure time (eg, type, intensity, variation, duration) and related physiologic responses (eg, ambulatory blood pressure and heart rate variability) for determining the underlying mechanisms for their opposite effects on global health," conclude the researchers.
By Nikki Withers