The effect of time-of-day and sleep deprivation on postural control: A systematic review

Background: Postural control (PC) can be affected by circadian rhythm and sleep deprivation, whereby it has been reported the result of PC measurement in clinical and experimental situations can be influenced by both factors. It has been suggested sleepiness can result in deficiency in PC, which in turn can lead to occupational accidents and subsequent injuries. This is while no study critically reviews or summarizes findings surrounding this topic in the literature. Research question: Is there any significant effect of sleep deprivation and circadian rhythm on PC variables among healthy individuals? Methods: PubMed, Web of Science, Scopus, and Embase were used to detect relevant studies. Only studies that examined the effect of time of day and/or sleep loss on PC among healthy individuals were included in this systematic review. Results: Forty-nine studies were included based on the inclusion criteria. Both circadian rhythm and sleep loss had a significant effect on PC, whereas there are inconsistent findings for optimal postural control regarding time of day. In terms of sleep deprivation, all investigations indicated that sleep loss deteriorates PC. Significance: The current systematic review represents a significant effect of circadian rhythm and sleep deprivation on PC, whereby it is suggested that clinicians and researchers consider these factors when measuring PC since it may affect the result of research and clinical test. Moreover, PC may be worsened through sleeplessness; however, some studies revealed there is no linear relationship between time of wakefulness and deteriorating PC due to the influence of circadian rhythm. Hence, while PC, as an objective tool, can help to detect those who are sleep deprived, which in turn can lead to prevent possible musculoskeletal injuries, further studies are needed to reveal more understanding about the effect of sleep loss and circadian rhythm on PC.