Associations between the living environment and sleep through the mediation of the physical activity: a systematic review

Objective
To review the role of physical activity as a mediator in the association between the living environment and sleep.

Materials and methods
Observational and experimental studies in English were included regardless of participants’ age, gender, or ethnicity. Searches were conducted in Medline (via PuMed), Scopus and Embase, supplemented by manual searches. Study selection was performed by two independent reviewers on the basis of titles, abstracts, and full-text articles. Data extraction and quality assessment (using JBI critical appraisal tools) were also carried out by two reviewers. The PRISMA 2020 guidelines were followed throughout.

Results
After removing duplicates, 1147 studies were screened, of which 5 studies (4 cross-sectional and 1 longitudinal) met the inclusion criteria. These studies were of moderate methodological quality. Improved access to recreational facilities was indirectly associated with longer sleep duration, lower risk of wake after sleep onset (WASO) and later wake time through increased physical activity. Strengthened neighborhood social cohesion, and reduced neighborhood violence and problems (i.e., noise, lack of access to shops and parks, litter, etc.) were indirectly associated with longer sleep duration, a lower risk of short sleep duration and better sleep quality through increased physical activity.

Conclusion
Physical activity appears to be a potential promising mediator between the living environment and sleep, but evidence remains limited due to the small number of studies on this topic. Future studies using a rigorous mediation methodology and including household-level factors are needed