The complex interrelationship of sleep and circadian rhythmicity with falls risk and postural control in healthy adults in the field and in the laboratory: Effects of sex, sensorial feedback and work environment

Shabana, Ziad (2025) The complex interrelationship of sleep and circadian rhythmicity with falls risk and postural control in healthy adults in the field and in the laboratory: Effects of sex, sensorial feedback and work environment. Doctoral thesis, University of East Anglia.

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Abstract

Background: Postural control is fundamental for maintaining balance and stability during daily activities and work-related tasks. Impairments in postural control increase the risk of falls and accidents, particularly among aging populations and in high-risk occupational settings. Sleep and circadian rhythmicity are critical physiological processes that support neural functions underlying postural control. Disruptions in sleep and circadian rhythms, common with aging, certain health conditions, and shift work are major risk factors for adverse health outcomes, including falls. However, the specific impact of sleep propensity and circadian rhythmicity on postural control as individuals age remains unclear, as does the influence of sensory feedback and sex on this relationship. Additionally, the extent to which lengthy work hours, shift work, and insufficient sleep contribute to fall risk in hazardous occupations is not well understood. The current study aimed to address these gaps through comprehensive observational and experimental research, focusing on how sleep and circadian factors affect postural control in aging populations and high-risk occupational environments.

Methods: The first study investigated the intricate relationship between sleep and circadian rhythmicity in older men and women and consisted of an observational and an experimental phase. In the observational phase older adults (N=166) with no cognitive impairment underwent a comprehensive screening assessing sleep, lifestyle, mental health, and self-perceived risk of falls. In phase two a subgroup of the screened participants (N=38) took part in a randomized experimental laboratory-based study involving 40 hours of sleep deprivation or multiple naps to assess the effect of sleep restriction, time of the day and sensorial feedback on balance control. Subjective and objective vigilance, visuo-motor coordination, and postural control were assessed at four-hourly intervals throughout the session. Postural control was characterized by quantifying the dynamics of the body’s center of pressure using a force plate under varying visual and haptic feedback conditions.

The second study investigated the feasibility of remotely assessing sleep and postural control in a group of mariners on duty (N = 105), who completed multiple questionnaires concerning health, lifestyle, work patterns, sleep, and fall-related concerns.

Results: In the community-dwelling cognitively healthy older adult cohort, higher self-perceived risk of falls was associated with poorer reported sleep quality as well as with lower self-reported mental and physical health. There were also some sex differences, with women reporting worse sleep quality and showing a significantly stronger association between falls concerns and physical health, whereas men showed a significantly stronger association between falls concerns, age, and bedtime. Interestingly physical health was the only independent predictor of self-perceived risk of falls when all potential predictors were included in a multivariate model. In the experimental study sleep restriction did not have an independent effect on postural control but increased the subjective effort to maintain balance. Moreover, sleep deprivation disrupted postural stability substantially more in males, particularly in the eyes-open sensorial condition. The remote assessment of self-reported sleep, lifestyle and wellbeing and falls risk in mariners proved feasible and showed that longer self-reported sleep latency was associated with increased falls concerns in this population.

Conclusions: The findings provide a better mechanistic understanding of the multifaceted nature of postural control, indicating that older men with sleep disturbances are at increased risk of falls, particularly at night and in dim light conditions. Increased sleep latency, commonly associated with sleep-onset insomnia, appears to correlate with falls concerns in mariners. The current study suggests that tailored fall prevention strategies should consider the effects of sex, sensory context, sleep, and circadian disruption in both community and occupational settings.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Medicine and Health Sciences > School of Health Sciences
Depositing User:	Chris White
Date Deposited:	05 Jan 2026 11:31
Last Modified:	05 Jan 2026 11:31
URI:	https://ueaeprints.uea.ac.uk/id/eprint/101511
DOI:

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