Purpose: To examine the relationship between sleep quality and duration and muscle strength among community-dwelling middle-aged and older adults.
Methods: A systematic review was conducted from March 2020 until May 2020. Searches were done for peer-reviewed and English-written articles reporting results of studies in PubMed, Embase, Scopus, Cochrane Library, and in article references lists. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses was used as well as the Newcastle-Ottawa Scale (NOS) to appraise the methodological quality.
Results: Twenty-one cross-sectional, three prospective studies and a total of 92,363 subjects were included. The majority of the included studies are classified as "high quality". Handgrip strength is the main method of muscle strength assessment. Sleep assessment is usually conducted using subjective measures, such as validated sleep scales or self-reported questionnaires. Actigraphy, as an objective measure, is used less often. Most studies support strong evidence on the association between weak muscle strength and poor sleep quality and duration among middle-aged and older adults; whereas the results for the gender-specific association and the impact of short or long sleep duration were inconclusive.
Conclusion: This review has identified strong evidence on the relationship between sleep quality and duration and muscle strength among middle-aged and older adults. Health professionals should consider this relationship as a component of geriatric assessment in community practice and geriatric settings. Future rigorous research with a combination of subjective and objective measurements is needed to explore whether gender and specific sleep duration are related to muscle strength.
Keywords: Hand strength; Knee extension; Muscle strength; Older adults; Sarcopenia; Sleep.