The effect of exercise on daytime sleepiness in healthy individuals

The effects of exercise on daytime sleepiness remain unclear, with conflicting findings in the literature. We reviewed the existing literature on the relationship between exercise and daytime sleepiness in healthy individuals. We conducted a systematic search of PubMed and Google Scholar (1991 to present) for interventional studies that used the Epworth Sleepiness Scale (ESS) to measure change in self-reported degree of sleepiness before and after an exercise regimen. Seven studies were included in the review. Exercise significantly improved self-reported sleepiness after the intervention, as measured by ESS, in 4 of the 7 studies; the other studies indicated no significant difference. Additionally, exercise interventions enhanced sleep quality, evident in lower Pittsburgh Sleep Quality Index scores in 4 of 5 studies, thus indirectly alleviating daytime sleepiness. Results were variable and influenced by exercise type, intensity, and timing, as well as participant adherence. Factors that may contribute to the effect of exercise on daytime sleepiness include improved sleep quality, regulation of circadian rhythms, neurotransmitter release, stress reduction, increased energy levels, and weight reduction. This review suggests benefits of exercise for reducing daytime sleepiness and improving sleep quality. Future research is essential for assessing the mechanisms of these effects.