A new study found that sleep disturbances in older adults are associated with an increased risk of dementia and death. In this longitudinal study of 2,812 seniors aged 65+, researchers examined the relationship between sleep disturbances and the incidence of dementia and all-cause mortality over a 5-year period.
Older adults who took longer to fall asleep and got less than 5 hours of sleep per night were 2x more likely to develop dementia than those who got adequate sleep (7-8 hours/night). Additionally, study participants who had trouble staying alert during the day, took routine naps, had poor sleep quality, or got less than 5 hours of sleep per night were more likely to die of any cause.
One of the functions of sleep is to clear toxic metabolites from the brain. As such, the authors hypothesize that a shorter duration of sleep may result in a buildup of these metabolites in the brain, increasing the risk of dementia. Furthermore, when examining all-cause mortality, the authors hypothesize that underlying disease may interfere with normal sleep/wake cycles and thus increase the likelihood of dying.
Go deeper: If you are looking for resources to help you improve your sleep, check out our Sleep section here.