Although people fear health problems like cancer, surveys show that one of the deepest fears is that of developing Alzheimer’s disease or another form of dementia. Here’s a fact. According to the Alzheimer’s Association, one in three seniors dies with Alzheimer’s disease. Brain health is something we shouldn’t take for granted as we age.
Unfortunately, it is not clear what causes Alzheimer’s disease. However, studies show that certain proteins build up in the brain that ultimately reduces the brain’s function and makes it harder to retrieve information. Researchers have also discovered a link between sleep, brain health, and Alzheimer’s risk. We know sleep is vital for good mental and physical health, but could not sleeping enough also raise your risk of Alzheimer’s disease?
How Lack of Sleep Disrupts the Brain
As mentioned, abnormal, misfolded proteins accumulate in the brains of those with Alzheimer’s disease. Two of these proteins are called tau protein and beta-amyloid. In people with Alzheimer’s, these proteins build up and clump together to form plaques and tangled, misshapen proteins. In fact, they accumulate around nerve cells or neurons and disrupt their function. When connections between nerve cells are blocked, the brain gradually shrinks in volume. It is common to have some brain shrinkage with age, but people with Alzheimer’s disease have a more pronounced loss of brain volume.
Alzheimer’s sufferers also have problems clearing abnormal proteins that build up. Normally, that’s the job of specialized cells called glial cells. These cells actively “eat” the amyloid and tau proteins in normal people, but people with Alzheimer’s disease have glial cells that are less efficient at clearing out these proteins. As the glial cells build-up in an attempt to clear the proteins, it leads to chronic brain inflammation.
What does this have to do with sleep? In mouse studies, lack of sleep not only slows the clearance of these brain toxic proteins, but it also speeds up the spread of the proteins throughout the brain. One study found that sleep deprivation boosted the amount of amyloid and tau protein in the spinal fluid by 30% and 50% respectively. That’s a clear sign that something’s going on in the brain of people who don’t sleep enough.
Sleep as an Early Symptom of Alzheimer’s Disease
Not only does lack of sleep slow the clearance of tau and amyloid from the brain, but sleep disturbances may also be an early sign of the disease. According to the National Sleep Foundation, sleep disturbances are common in people with Alzheimer’s disease. However, sleep problems can be an early sign of dementia and present even before memory problems develop.
In a study, researchers compared the sleep patterns of 145 individuals with spinal fluid markers of Alzheimer’s disease. What they found was that almost 20% of the participants had markers suggestive of early Alzheimer’s disease based on their spinal fluid markers. After tracking their sleep habits using wrist sensors, researchers found those with early Alzheimer’s disease tended to have less healthy sleep patterns compared to healthy individuals without preclinical Alzheimer’s disease.
Therefore, a change in sleep patterns could be an early warning signal that something’s going on in the brain. However, there are a variety of reasons people have problems sleeping ranging from medications to poor sleep hygiene. So, sleep disturbances don’t necessarily signal a high risk of developing Alzheimer’s disease.
Even One Night of Poor Sleep is Unhealthy
We know that chronically sleeping too little is harmful to overall health, but even one night of sleep can impact brain health. You’ve probably experienced some effects of sleeping poorly or not enough – fatigue, brain fog, and lack of motivation. You simply want to hit the sack and snooze! Yet even a single night of poor sleep impacts the brain. A study found that after a single night of sleep deprivation, subjects had higher levels of amyloid protein in their spinal fluid. It’s doubtful that an occasional night of missed sleep dramatically increases the risk of dementia, but it suggests that even short-term sleep deprivation has an effect on the brain.
When you sleep, your body goes through sleep stages. During the first part of the night, you normally have more non-rapid eye movement sleep. (NREM). This phase of sleep is when you consolidate memories that you formed during the day. But as the night goes on, you enter periods of rapid eye movement sleep. (REM) It’s during REM sleep that you breathe faster and your heart rate increases to a level almost as high as when you’re awake. Most dreaming occurs during REM phases of sleep. A study found that individuals with higher levels of tau protein in their brain experienced less NREM sleep. In other words, their brains aren’t getting the sleep they need to transfer memories to long-term storage.
Lower Your Risk of Alzheimer’s Disease
There’s still much to learn about Alzheimer’s disease and the role sleep plays in the risk of developing it. However, based on what we know, getting quality sleep is one thing you can do to lower your risk. Fortunately, not everyone who has high levels of amyloid and tau protein in their brain develops memory problems. It’s possible that individuals who continue to have good memory despite higher levels of these proteins built up lots of brain reserve throughout life by being socially active and learning new things. Studies show that speaking two languages, for example, is linked with a lower risk of Alzheimer’s disease. Learning a new language or a new skill later in life may help too. When you learn something new, your brain forms new connections that can bypass damaged areas of the brain. Studies also suggest that staying physically active improves brain function and may prevent or delay the onset of Alzheimer’s disease.
The Bottom Line
Sleep matters for many reasons, including the health of your brain. Don’t underestimate the importance of a good night’s sleep! You need it for a healthy brain and for overall wellness. So, don’t skimp on shut-eye!
References:
· Alzheimer’s Association. “Facts and Figures”
· National Institute of Aging. “What Happens to the Brain in Alzheimer’s Disease?”
· Mayo Clinic. “Alzheimer’s disease: Can exercise prevent memory loss?”
· Holth JK, et al “The sleep-wake cycle regulates brain interstitial fluid tau in mice and CSF tau in humans” Science 2019.
· National Sleep Foundation. “Sleep Loss Precedes Alzheimer’s Symptoms”
· de Almondes KM, Costa MV, Malloy-Diniz LF et al. (2016) Insomnia and risk of dementia in older adults: Systematic review and meta-analysis. J Psychiatr Res 77, 109-115.
· Sci Transl Med. 2019 Jan 9;11(474). pii: eaau6550. doi: 10.1126/scitranslmed.aau6550.
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