Associations of accelerometer-measured sedentary behavior and physical activity with sleep in older adults.

BACKGROUND

Few studies have examined the non-linear relationships of objectively-measured sedentary behavior and physical activity with insomnia symptoms in older adults. We investigated such relationships of sedentary and physically-active behaviors with total sleep time and nocturnal wakefulness.

METHODS

We recruited adults aged 60 years and above who have received health check-ups or been to geriatric outpatient services from a hospital setting. Sedentary and physically-active behaviors, total sleep time, and wakefulness time after sleep onset were measured by Actigraphy, and their relationships were estimated using generalized additive models.

RESULTS

The 157 older adults receiving health-related services slept 7.5 h (20.8 min awake) on average per day. Total sleep time was negatively associated with sedentary and physically-active behaviors. By contrast, a U-shape relationship was found between sedentary behavior and wakefulness time after sleep onset, with a turning point at a daily sedentary time of 10.9 h.

CONCLUSION

Longer high-intensity physical activity time was related to a shorter wakefulness time after sleep onset. By contrast, daily sedentary time longer than 10.9 h was related to shorter total sleep time but more nocturnal wakefulness time. Future nonpharmacological strategies for sleep improvement should consider the sedentary threshold.