Sweat, Sit, Sleep: A Compositional Analysis of 24‐hr Movement Behaviors and Body Mass Index among Children with Autism Spectrum Disorder

This study (a) examined the daily composition of 24‐hr movement behaviors in children with ASD using objective measures, and (b) applied compositional analysis to examine the associations of the time spent in moderate‐vigorous physical activity (MVPA), light physical activity (LPA), sedentary behavior (SB), and sleep duration (SD) with body mass index (BMI), relative to the time spent in the other movement behaviors in a sample of children (aged 7–19 years) with ASD. Time spent in MVPA, LPA, SB, and SD were measured using accelerometers over a 7‐day period. BMI was calculated from measured height and weight. Participants ( n = 46) spent 40% of time in LPA ( M = 9.6 hr), 30.6% ( M = 7.34 hr) in SB, 24.9% ( M = 5.98 hr) asleep, and 4.5% ( M = 64.8 min) in MVPA. Reallocating 30 min from LPA to SD decreased BMI by 0.471 kg/m 2 ( P = 0.003). Reallocating 30 min from MVPA to SD decreased BMI by 0.658 kg/m 2 ( P = 0.051). Reallocation of 60 min in equal proportions from SB, MVPA, and SD to LPA increased BMI by 0.418 kg/m 2 ( P = 0.021), and reallocation of 60 min in equal proportions from LPA, MVPA, and SD to SB increased BMI by 0.295 kg/m 2 ( P = 0.052). Finally, reallocation of 60 min in equal proportions from SB, LPA, and MVPA to SD decreased BMI by −0.845 kg/m 2 ( P = 0.001). Lay Summary Data was collected on time spent in light physical activity (LPA), moderate‐vigorous physical activity (MVPA), sedentary behavior (SB), and sleep in 46 children with autism. The sample had insufficient sleep (a mean of 6 hr/night). We showed that replacing 30 min of LPA or MVPA with sleep decreased BMI. Also, moving 60 min to LPA or SB from the remaining movement behaviors (i.e., 20 min from each) increased BMI, and moving 60 min to sleep from the remaining behaviors decreased BMI.