Sedentary Time and Physical Activity in Older Women Undergoing Exercise Training

Older adults have low rates meeting the physical activity (PA) guidelines and high sedentary time. Low PA and excessive sedentary time have been linked to adverse health outcomes. Less is known about whether exercise training influences sedentary time and PA in various intensities.

This study aimed to examine the effects of a 16-wk aerobic exercise training on time spent being sedentary and on light-intensity PA (LPA) and moderate- to vigorous-intensity PA (MVPA) and step numbers in older women.

Inactive women (n = 61; age = 65.5 ± 4.3 yr) participated in moderate-intensity walking of either a low or a moderate dose (33.6 and 58.8 kJ·kg body weight per week, respectively). They wore a SenseWear Mini Armband at baseline and at end intervention to determine sedentary, LPA, and MVPA time and step numbers.

Time being sedentary, or spent on LPA and MVPA, did not change differently by exercise groups with different doses (all P values for group-time interaction >0.580). Overall, time being sedentary reduced from baseline to end intervention by approximately 39 min·d (P < 0.001), and LPA increased by 19 min·d (P = 0.003). MVPA time increased (P < 0.001), which was primarily accounted for by the supervised exercise. Interestingly, daily steps increased more in the moderate-dose than the low-dose group (P = 0.023 for group-time interaction; 33.6% and 19.8% median increase in moderate- and low-dose groups, respectively). Also, there were individual differences in these changes.

Results indicated that, on average, older women did not reduce time of LPA or MVPA outside the exercise program or increase sedentary time as a result of participating in the exercise program.