Sleep and the Alzheimer's Connection
Can a lack of sleep lead to dementia or Alzheimer’s? Despite what some news headlines might suggest, researchers don’t really know. But, there are some important things they do know – like why sleep is so critical to our health.
A lot of research in recent years has pulled back the covers, so to speak, on the role sleep plays in our health. Beyond the obvious – it helps restore us and takes away that sense of tiredness that grows the longer we’re awake – it also helps in less obvious ways and they are critically important.
Why Sleep is Important
“It helps us with consolidation of memory,” says Dr. Steven Barczi, UW Health geriatrician and one of a handful of geriatric sleep physicians in the country. “Certain aspects of sleep help us consolidate certain things from the preceding day. We learn new information, experience new things, we might have emotional events that occur. And the brain has to decide what to do with that.”
The brain processes that information in a few different ways – it can disregard it or it can store it. Dr. Barczi uses the example of breakfast – what you ate three weeks ago generally isn’t an important piece of information, so the brain will discard that. Unless it was a really memorable meal (or you eat the same thing every day) chances are you can’t recall exactly what you had. But if you learn that someone has a baby, or receives a medical diagnosis, or you experience an emotionally charged situation – those events usually imprint on us. They are reinforced through deep or slow wave sleep.
“Sleep has a way of pruning out what’s not important and storing or reinforcing the neural networks for more important information,” he adds.
Sleep also plays an important role in our emotional and physical health. If you experience a bad night of sleep or hardly sleep at all, Dr. Barczi says, you may notice that you’re a little more prone to react or perhaps say things you wouldn’t – or shouldn’t – normally say. Sleep helps us regulate that.
Similarly, it helps the whole body. People who experience poor sleep may have difficulty regulating their blood pressure, for example.
What Happens When You Don’t Get Enough Sleep
For most people, 7 to 8 hours is enough. There are those who may need as little as 6, while others may require 10 to 11 to avoid feeling exhausted and tired all day. If you’re feeling tired and fatigued the next day, chances are you’re not getting enough, or you’re not getting enough quality sleep.
When we experience poor sleep, it could lead to physical factors we may not immediately notice – headaches, feeling foggy, short attention spans or even difficulty remembering things.
A number of things can contribute to poor sleep – and not just having infants and young children. Anxiety, caffeine, medications and sleep disorders like sleep apnea are just a few common ones. Even aging.
“Sleep is a biological rhythm – a circadian rhythm. It tries to maintain regularity and rhythm, including sleep and waking. But as we age, those internal clocks can become desynchronized – and this is important when we start to talk about individuals with health problems, like those with memory illness or dementia,” says Barczi.
Because sleep can be disrupted in those with dementia and memory problems, their emotional state can become more labile, or easily altered. And that “sleep debt” can make them more prone to acting out or saying things. They may not be as attentive, and as a result, more prone to falls or accidents. And it can be even more challenging for them to recall information or learn something new.
The Connection Between Sleep and Dementia and Alzheimer’s
But back to that original question - what about that connection between lack of sleep and dementia or Alzheimer’s?
First a brief clarification – it’s important to understand that Alzheimer’s and dementia are not the same thing. Dementia is a syndrome - or an umbrella term used to describe a group of symptoms that may lead to problems with different thinking abilities, including memory, Dr. Nathaniel Chin, UW Health geriatrician, explains. Eventually, the thinking problems impact a person’s function, or their ability to do routine day-to-day tasks, including driving, cooking, cleaning and managing medications.
“Alzheimer’s disease is the number one cause of dementia – causing up to 80 percent of dementia cases,” he says. “However, there are other causes of dementia, too, including vascular disease and Parkinson’s.”
In Alzheimer’s disease, an abnormal process occurs in the brain that leads to brain cells dying. That process can lead to memory or thinking problems, because the cells responsible for those brain functions are no longer there to do their job. Because of what’s happening in the brain, people with Alzheimer’s may experience disrupted sleep. And medications and supplements commonly used in managing Alzheimer’s disease may contribute to poor sleep, as well. But at this point, it’s not known how much chronic lack of sleep leads to Alzheimer’s.
Common side effects of poor sleep – including high blood pressure or depression – can be risk factors for developing Alzheimer’s disease, but there are several risk factors - including one we have no control over: age.
“Anyone can develop Alzheimer’s disease. There are factors which can increase our risk, including diabetes and obesity, and in late onset Alzheimer’s disease – roughly defined as the development of dementia due to Alzheimer’s disease after the age of 65 – there is a genetic component that increases a person’s risk,” says Dr. Chin.
Dr. Chin, who is also a researcher with the Wisconsin Alzheimer's Disease Research Center, adds that there is a gene called APOE and while having APOE4 increases your risk of developing Alzheimer’s, it doesn’t mean you’re guaranteed to develop it.
“Of all the people who have dementia due to Alzheimer’s disease, 40 percent have the APOE4 gene, which means the majority do not,” he says. In mice studies, APOE has been shown to be involved in the brain’s ability to clear out a protein called beta-amyloid during sleep. A build up of beta-amyloid is often present in the brain of those who have Alzheimer’s. In studies, those who have the higher-risk gene may not be able to “clean out” the brain of the protein when they experience poor sleep. However, Dr. Chin stresses that more studies are needed before any conclusions can be made.
As for dementia, studies have shown associations between developing dementia and sleeping less than 6 hours or more than 9 each day. But again, these studies did not show sleep issues as causing dementia – only that there was a relationship between the two, Dr. Chin says.
“It’s also important to remember that the diagnosis of dementia requires marked changes in thinking as well as poorer performance on brain testing. Both of these can be influenced by poor sleep, particularly if the poor sleep is longstanding,” he adds.
So the takeaway at this point is: the best thing you can do is make sleep a priority, both in terms of quality and quantity – and talk with your primary care provider about your concerns.
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Date Published: 06/12/2018