The Connection between Lack of Sleep and Dementia


We know that failing to get enough sleep can seriously mess with your head – and that’s not a metaphor. There’s an established link between lack of sleep and memory issues, performance issues, and even the presence of symptoms of depression and anxiety. Now, recent studies have begun adding an additional possible issue that results from sleep deprivation to the list: the development of dementia. 

Dementia is a blanket term for a wide range of symptoms associated with a decline in memory and other thinking skills. Although Alzheimer’s disease comprises roughly 60-80% of the cases, the category includes other types of dementia such as vascular dementia, which can be brought on as a result of a stroke. Regardless of the cause, this cognitive decline can eventually become severe enough to interrupt a person’s ability to perform daily activities.

The (often bad) relationship between dementia and sleep is well documented. People with dementia will frequently experience sleep issues ranging from sleep disturbances to a mood state called “sundowning,” which is a tendency to become restless or agitated in the late afternoon and early evening. Although specific causes are still unclear, one prevailing theory is that sleep disturbances and reduced sleep quality lead to sleepless nights and drowsy days. This can upset one’s internal clock and cause a biological mix-up of day and night, leading to difficulties falling or staying asleep at night and taking long naps during the day.

But lack of sleep doesn’t just plague those who have dementia; recent studies are showing that chronic sleep deprivation may contribute to the development of dementia. One possible reason for this is that during sleep, our brains clear out toxins that accumulate during the day. One such toxin is beta amyloid, which is a protein that can kill brain cells and slow information processing. Beta amyloid is strongly linked to the development of Alzheimer’s disease and dementia. Less sleep means an inability to clear out these toxins, and as the toxins add up so too does the risk of developing dementia. A study that followed adults for 12 years and documented their sleep habits and potential dementia development found that those who spent more time in REM sleep at night had a lower risk of developing dementia (and vice versa).

Before you panic, this research is still in its early stages and a true causal link has yet to be established. Researchers have referenced this as a “chicken and egg” scenario – no one is entirely sure if poor sleep causes dementia, if dementia causes poor sleep, or (most likely) some combination of both. However, given the existing research on the benefits of sleep, trying to get more sleep can help more than just your risk of dementia.

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