WEDNESDAY, Dec. 18, 2013 (HealthDay News) -- For older women, more than 65 percent of waking hours are spent in sedentary behavior, although the sedentary bouts are usually of short duration, according to a research letter published in the Dec. 18 issue of the Journal of the American Medical Association.
Eric J. Shiroma, M.Ed., from the Harvard School of Public Health in Boston, and colleagues assessed physical activity and sedentary behavior using accelerometers for 7,247 women (mean age, 71.4 years) from the Women's Health Study. Women were asked to wear an accelerometer for seven days during waking hours and to complete a wear time diary.
The researchers found that 65.5 percent of wear time was spent in sedentary behavior, which was equivalent to 9.7 hours per day. There were a mean of 85.9 sedentary bouts (defined as consecutive minutes in which the count per minute was less than 100) per day, with 9.0 breaks (at least 1 minute in which counts registered 100 or more following a sedentary bout) per sedentary hour. As age and body mass index increased, the total sedentary time increased and the number of bouts and breaks decreased, after adjustment for wear time and smoking status (P < 0.001). Most sedentary bouts were of shorter duration, with the mean percentage of bouts of 30 minutes or more being 4.8 percent, representing 31.5 percent of total sedentary time.
"We found that older women spent about two-thirds of waking time in sedentary behavior, most of which occurred in bouts lasting less than 30 minutes," the authors write.
Two authors disclosed being members of the Actigraph scientific advisory board.
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