Sedentary time is the time that adults spend in a seated, inactive position. It is becoming more common for adults to engage in sedentary activities in Western societies. However, we know that inactive lifestyles negatively impact our health. We also know that exercise provides many health benefits, such as warding off diseases and managing weight.
Researchers wanted to examine the association between objectively measured sedentary behavior (total time and length of time sitting still) and all-cause mortality. The study, published in Annals of Internal Medicine, found that both the total volume of sedentary time and time for each session are associated with all-cause mortality. This suggests that physical activity guidelines should target reducing and interrupting sedentary time to reduce the risk of death.
About the study
The prospective cohort study pooled 7,985 black and white participants aged 45 years or older. Sedentary time was measured using a hip-mounted accelerometer. Participants wore the device for 10 or more hours a day for 4 or more days. Over a median follow-up of 4 years, 340 participants died (4.2% of participants).
Compared to the rest of the participants, the participants who died had:
- A total sedentary time of 13.3 or more hours a day compared to less than 11.5 hours a day
- An uninterrupted sedentary period of 12.4 or more minutes compared to less than 7.7 minutes
- A total sedentary time of 12.5 or more hours a day and uninterrupted sedentary period was 10 or more minutes
- A total sedentary time of 12.5 or more hours a day and uninterrupted sedentary period was less than 10 minutes
How Does This Affect You?
Cohort studies are observational studies. These studies simply observe events as they unfold, but do not interfere or introduce factors that can affect the outcome. This is a large study, which generally increases the reliability of outcome. Previous studies have relied on self-reporting to evaluate sedentary time as a risk factor for mortality. This study used a device to measure that data objectively.
Sedentary time is associated with all-cause mortality. If you life a sedentary lifestyle, start moving. Break up periods of sitting with movement. Even short walks can help. When possible walk instead of taking the car. Set aside time for physical activity. Adults should aim for at least 150 minutes a week of moderate intensity or 75 minutes a week of vigorous intensity aerobic activity.
RESOURCES
US Centers for Disease Control and Prevention http://www.cdc.gov
US Office of Disease Prevention and Health Promotion https://health.gov
References
2008 physical activity guidelines for Americans Summary. Office of Disease Prevention and Health Promotion website. Available at: https://health.gov/paguidelines/guidelines/summary.aspx. Accessed April 30, 2018.
Adult preventative health. EBSCO DynaMed Plus website. Available at: https://www.dynamed.com/topics/dmp~AN~T901928/Adult-preventative-health . Updated April 5, 2018. Accessed April 30, 2018.
Diaz KM, Howard VJ, et al. Patterns of sedentary behavior and mortality in U.S. middle-aged and older adults: a national cohort study. Ann Intern Med. 2017 Oct 3;167(7):465-475.