Monitoring Physical Activity Levels and Sleep Pattern Relationships in Boys With Duchenne Muscular Dystrophy

PURPOSE: Duchenne muscular dystrophy (DMD) is the most prevalent and lethal of all muscular dystrophies. DMD results in degeneration of skeletal muscle and loss of function in young boys. During the course of progressive functional decline, two pervasive problems impair quality of life: (1) limitations in physical activity and (2) poor sleep. In the general population, these two problems are physiologically and behaviorally linked. Lack of appropriate and balanced physical activity throughout the day is a root cause of poor sleep at night. However, there is a dearth of information on appropriate levels of physical activity for boys with DMD, likely because of the contraindications of high-impact, resistance, or ballistic movements, which irreparably damage muscles. This study addresses a significant gap in our understanding of the just-right levels of physical activity, provides evidence on dose–response relationships between physical activity and sleep, and explores the relationship between physical activity and sleep and quality of life (QoL) in young boys with DMD.

METHOD: A quasi-experimental design was used to explore the relationship between physical activity, sleep efficiency, and QoL in young boys with DMD aged 5–9. Thirty boys with DMD were recruited through the local Muscular Dystrophy Association and the national DuchenneConnect registry. Pearson product–moment correlation was used to determine the strength and direction of the relationship between the variables physical activity, sleep, and QoL. A repeated measures analysis of variance examined change over time on each of the outcome variables. All data were collected in the natural environment.

Boys with DMD wore an activity monitor on their nondominant hand 10 hr/day and throughout the night for 30 days. A special application that captures raw data from available sensors on the activity monitor was used for data capture. On a daily basis, deidentified raw data were logged and pushed to a secure cloud service via Wi-Fi by the parent. At baseline and end of study (30 days), we collected personal demographics and the self-report Pediatric Quality of Life Inventory (PedsQL).

RESULTS: We observed strong associations between the amount of physical activity achieved during the day (specifically, step counts) and same-day sleep efficiency in these boys (r =.79, p < .000). Significant correlations also were found between PedsQL scores and physical activity (r = .62) and sleep (r = .43). Daily variations in the boys’ physical activity and sleep were significant throughout these time series data (p < .01). The boys seldom achieved optimum sleep efficiency (85%–100%). No changes in PedsQL scores occurred over the 30-day time frame. Interestingly, data for some boys demonstrated that both extremely high and low levels of physical activity equated to low sleep efficiency, whereas moderate levels equated to moderate or high sleep efficiency. This is different from typical health promotion guidelines, which generally prescribe increased amounts of physical activity for overall health.

CONCLUSION: Data gleaned provide caregivers and clinicians with important knowledge regarding just-right amounts of physical activity during the day for better sleep at night in boys with a neuromuscular disorder.

IMPACT STATEMENT: Providing parents with the objective knowledge they need to make informed decisions about levels of daily physical activity to enhance their child’s nighttime sleep and overall well-being would be a significant contribution to this and other pediatric populations. Moreover, it is possible that a directed intervention focused on just-right levels of physical activity may help improve sleep efficiency in boys with DMD. This is a novel idea and has not been studied in this population.

References

Bloetzer, C., Jeannet, P. Y., Lynch, B., & Newman, C. J. (2012). Sleep disorders in boys with Duchenne muscular dystrophy. Acta Paediatrica, 101, 1265–1269. https://doi.org/10.1111/apa.12025

Kredlow, M. A., Capozzoli, M. C., Hearon, B. A., Calkins, A. W., & Otto, M. W. (2015). The effects of physical activity on sleep: A meta-analytic review. Journal of Behavioral Medicine, 38, 427–449. https://doi.org/10.1007/s10865-015-9617-6

Schaefer, S. E., Van Loan, M., & German, B. (2014). A feasibility study of wearable activity monitors for pre-adolescent school-age children. Preventing Chronic Disease, 11, 130262. https://doi.org/10.5888/pcd11.130262

Vriend, J. L., Davidson, F. D., Corkum, P. V., Rusak, B., McLaughlin, E. N., & Chambers, C. T. (2012). Sleep quantity and quality in relation to daytime functioning in children. Children’s Health Care, 41, 204–222. https://doi.org/10.1080/02739615.2012.685039