Alterations in the Myokine Concentrations in Relation to Sarcopenia and Sleep Disturbances: A Narrative Review

Objectives: In this study, our aim is to summarise the available data on the correlation between sarcopenia and sleep disturbances as a consequence of changes in the myokine concentrations. Methods: Our research was conducted by searching through PubMed, Mendeley and Google Scholar. In our analysis, 63 studies are included from the years 2011 to 2025. Among these studies, there are clinical trials, cross-sectional studies, reviews, systematic reviews and meta-analyses. Discussion: There is vast evidence confirming that sleep disturbances are more common among sarcopenic patients. On the other hand, sarcopenia is frequently observed among people with worse quality of sleep. It is also well documented that sarcopenia leads to changes in the myokine serum concentrations, and similar changes are observed among people suffering from sleep disturbances. Sarcopenic patients have lower levels of irisin, BDNF (brain-derived neurotrophic factor), meteorin and IL-15 (interleukin 15) and higher concentrations of FGF-21 (fibroblast growth factor 21) and interleukins 1β, 6 and 10. Lower levels of irisin, BDNF and meteorin, and higher levels of FGF-21 and interleukins 6 and 10, lead to sleep disturbances, like insomnia, reduction of REM (rapid eye movement) sleep time and lower slow-wave activity during the NREM (non-rapid eye movement) sleep phase. These changes are also observed in obstructive sleep apnea (OSA). More severe OSA is correlated with lower levels of irisin and meteorin and higher levels of FGF-21 and interleukins 6 and 8. Conclusions: Taking into account the similarities in the myokine concentration changes in sarcopenia and in sleep disturbances, it may be concluded that alterations in the myokine levels induced by sarcopenia provoke sleep disturbances. However, it is necessary to further investigate these correlations to understand them better.