Sex Differences in Insomnia Symptoms and Sleep Duration as Risk Factors for Walking Speed Decline in Older Adults

To examine the impact of insomnia symptoms and sleep duration on the progression of walking speed decline over time separately in men and women.

Longitudinal study.

A sample of 3208 participants aged 60 years or older from the English Longitudinal Study of Ageing (ELSA), followed for 8 years.

Participants without mobility limitations (walking speed >0.8 m/s) at baseline were included. Insomnia symptoms were assessed using a questionnaire adapted from the Jenkins questionnaire. Sleep duration was categorized as short (≤6 hours), ideal (7 to <9 hours), or long (≥9 hours). The outcome measured was the decline in walking speed (m/s). Generalized linear mixed models stratified by sex were employed to estimate the rate of decline in walking speed based on insomnia symptoms and sleep duration, while adjusting for sociodemographic, behavioral, clinical, and anthropometric factors.

No differences in walking speed were observed at baseline between men and women based on insomnia symptoms and sleep duration. After 8 years of follow-up, only men with long sleep duration (≥9 hours) experienced a greater decline in walking speed (-0.011 m/s per year; 95% CI, -0.021 to -0.001) compared with those with ideal sleep duration (-0.21 m/s over 8 years). Short sleep duration and insomnia symptoms were not associated with a decline in walking speed in either sex.

A long sleep duration (≥9 hours) is a risk factor for a decline in walking speed among men aged 60 years and older. Routine assessment of sleep duration in primary care provides a low-cost, scalable strategy to identify older adults at risk and guide early interventions aimed at maintaining mobility and independence, especially among older men.