The rise of overweight/obesity (OW/OB) in active-duty military personnel impacts physical performance and military readiness. Behavioral weight management programs within the military are designed to target behavioral components related to OW/OB, including increasing physical activity (PA) and optimizing sleep. Most studies use self-reported assessments of PA and sleep efficiency, which are known to suffer from bias. The aim of the present study was to determine the impact of a behavioral weight management program on objective measures of PA and sleep efficiency among active-duty military personnel with OW/OB. We hypothesized PA and sleep efficiency would improve significantly from baseline to 6 months post-intervention.
Participants with a minimum of 4 days of valid accelerometer data were included in analyses (n = 39). PA was measured as the average percent of time daily participants were recorded engaging in light or moderate/vigorous (MVPA) activities. Sleep efficiency scores, the ratio of total sleep time to total time in bed, were derived from wrist-worn accelerometer data. Paired samples t-tests were conducted to compare PA and sleep efficiency variables before and 6 months after the behavioral weight management intervention.
Participants were 30.6±6.9 years at the start of the intervention; 60% were female and 65% were White. Sleep efficiency significantly improved from baseline (M=80.4%; SD=6.9%) to 6 months post intervention (M=86.7%; SD=5.7%, T=5.64, p < .001); however, PA did not significantly change. At six months, the mean percent of time daily that participants engaged in light PA (M=14.1%; SD=4.7%) and MVPA (M=8.5%, SD=3.1%) did not significantly differ from participants’ mean percent of time engaged in light PA (M=14.7%, SD=4.0%) or MVPA (M=9.5%, SD=3.7%) at baseline.
Participants maintained relatively high levels of PA six months post-intervention, with no significant changes in daily time engaged in light or MVPA. Importantly, results support significant improvements in sleep efficiency six months post-intervention. Sleep efficiency scores of 90%+ are considered healthy in young adults and scores of 80%+ are considered healthy in older adults, thus participants in this young to middle-aged adult sample, on average, improved their scores to fall within the healthy range. Although improvements in sleep efficiency may or may not be related to the behavioral intervention, improving sleep is critical to supporting health and well-being.