Is There a Link Between Sleep and Alzheimer's Disease?

One in three Americans do not get enough sleep, and 45% of the remaining world’s population doesn't either. The US Centers for Disease Control and Prevention calls that a "public health problem," because disrupted sleep is associated with a higher risk of physical and mental conditions including diabetes, stroke and cardiovascular disease. There is evidence suggesting that there is a link between lack of sleep, Alzheimer’s disease, and dementia.Last year a study published in Neurology, the journal of the American Academy of Neurology, found that people who get less REM, or dream-stage sleep, may be at higher risk for developing dementia. REM is the fifth stage of sleep when the eyes move, the body heats up, breathing and pulse quicken, and the mind dreams.  The study found that people who took longer than the typical 90 minutes to enter REM were more likely to get dementia. They also spent only about 17% of their time asleep dreaming, compared to 20% in those who did not develop dementia. No association with dementia was found for any of the other four stages of sleep.Additional studies conducted by researchers at Wheaton College in Illinois have drawn connections between sleep-disrupting breathing disorders, such as sleep apnea, and accumulated biomarkers for Alzheimer’s disease.  This article in The Washington Post outlines their findings.  According to Megan Hogan, one of the researchers, “During sleep…your brain has time to wash away all the toxins that have built up throughout the day.  Continually interrupting sleep may give it less time to do that.”  The researchers hypothesized that adults with breathing disorders might be able to reduce the risk of dementia or slow its progression by treating their breathing conditions with dental appliances or CPAP machines.It is not yet clear whether chronic sleep disruption actually causes dementia or whether it might be the other way around; it is possible that the very early stages of brain disease may be causing people to lose sleep.  Until the relationship between the conditions is understood, people with sleep disorders would be wise to play it safe by treating those conditions. Besides potentially reducing the risk of dementia, getting better sleep promotes good day-to-day cognition and reduces the risk of developing other serious health problems such as diabetes and heart disease. Getting a good night’s rest will go a long way toward supporting overall health for aging adults.Photo © Duard Van Der Westhuizen