How Many Hours of Daily Sitting Increases CVD Risk for Women?
A sedentary lifestyle puts women at greater risk for developing cardiovascular disease (CVD), according to a new study.
To reach this conclusion, the researchers of the Objective Physical Activity and Cardiovascular Health Study (OPACH) recorded the average daily sedentary time and mean sedentary bout duration of 5638 women aged 63 to 97 years who had not had a myocardial infarction or stroke.
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Sedentary behaviors were defined as all sitting or reclining with low energy expenditure (<1.5 metabolic equivalents).
The participants wore accelerometers for 4 to 7 days and were followed for up to 4.9 years for CVD events. Overall, there were 545 CVD events during 19,350 person-years.
After adjusting for covariates, the researchers determined that women who were sedentary for 11 or more hours a day (the highest recorded quartile) were more likely to have had a CVD event compared with women who were sedentary for approximately 9 or fewer hours a day (the lowest recorded quartile).
While adjustments for potential mediators like body mass index, diabetes mellitus, hypertension, and CVD risk biomarkers reduced the association, they did not eliminate its significance.
Longer bout time was also associated with higher risk for CVD, even after adjusting for covariates. Adjusting for CVD risk biomarkers reduced the association.
Participants who had both long sedentary time and long bout durations had a significantly higher risk for CVD compared with those with short sedentary time and short bout durations.
In fact, lower sedentary time of 1 hour per day was associated with a 12% lower risk for CVD and a 26% lower risk for heart disease.
In repeating the analyses for incident coronary heart disease (myocardial infarction or CVD death), the researchers found similar associations.
“Both high sedentary time and long mean bout durations were associated in a dose-response manner with increased CVD risk in older women, which suggests that efforts to reduce CVD burden might benefit from addressing either or both components of sedentary behavior,” the researchers concluded.
—Colleen Murphy
Reference:
Bellettiere J, LaMonte MJ, Evenson KR, et al. Sedentary behavior and cardiovascular disease in older women: the OPACH study. Circulation. 2019;139(8):1036-1046. https://doi.org/10.1161/CIRCULATIONAHA.118.035312.