Study shows that replacing sedentary behaviour, like sitting, with an equal amount of physical activity, standing, or sleeping can reduce the risk of death by 12%
It is well accepted that physical activity and getting enough sleep are beneficial for your health, while remaining sedentary, or inactive, is associated with higher risk of death. Surprisingly, the direct association of these activities with each other has never been formally investigated with respect to health outcomes. A landmark study by a research group at the University of Sydney examined the impact of replacing sedentary behaviours for an equal amount of physical activity on mortality.
The group analyzed the responses from 200,000 subjects, aged 45 and over, from a questionnaire inquiring about the number of hours in a day they spent sitting, standing, sleeping, walking, or in moderate-to-vigorous activity. For example, sitting in front of the TV would count toward sitting hours and walking or doing light housework would contribute to physical activity hours. To examine replacement activity effects, the researchers analyzed responses using a novel statistical analysis model and followed up with subjects after 4 years to determine the number of deaths that had occurred.
Their results showed that walking instead of sitting reduced the risk of premature death by 14%, and similarly, moderate-to-vigorous activity by 12%. The researchers even discovered that replacing sitting for standing resulted in a 5% decrease in risk of death, and in individuals who were getting less than 7 hours of sleep, replacing sitting with sleeping in a 6% decrease. In contrast, replacing walking or moderate-to-vigorous physical activity with any other activity examined, like sleeping or sitting, actually increased mortality risks by 7-18%.
The research group concluded that replacing sedentary behaviours with physical activity greatly reduces the risk of death in adults who were middle-aged and older. One limitation of this study is that actual behaviours were not replaced by each other, and therefore, it would be interesting to see whether similar health outcomes would be observed to complement the statistical analysis method used here.
Stamatakis E, Rogers K, Ding D, Berrigan D, Chau J, Hamer M, and Bauman A. All-cause mortality effects of replacing sedentary time with physical activity and sleeping using an isotemporal substitution model: a prospective study of 201,129 mid-aged and older adults. International Journal of Behavioral Nutrition and Physical Activity. Issue 12, Page 121-131, 2015.
University of Sydney Press Release: http://sydney.edu.au/news-opinion/news/2015/10/01/swap-the-couch-for-a-walk-to-avoid-an-early-death-.html
Written by Fiona Wong, PhD