The Connection Between Sleep and Alzheimer’s Disease

Sleep is critical to your health. If you don’t spend enough quality time on your sobakawa pillow at night, you’ll find yourself foggy-headed, lethargic, unmotivated, and reaching for unhealthy foods. Research has also found that quantity and quality of sleep affects our risk for Alzheimer’s disease. It’s what USA Today dubbed the ‘sweet spot’ when referencing a recent study that revealed that too little or too much sleep could increase the risk for Alzheimer’s.


Alzheimer’s disease is the most common type of dementia that begins with mild memory loss and progressively gets more severe. In some cases, a person with advanced Alzheimer’s can no longer speak or respond to their environment. It destroys cognitive skills and memory, making it difficult to carry out simple tasks. Currently, over 6 million Americans are living with the disease, and it is said to kill more people each year than breast cancer and prostate cancer combined. Another concerning statistic is that Alzheimer-related deaths have increased by 16% during the pandemic.


Research has identified various factors that increase one’s risk of acquiring Alzheimer’s, including lifestyle, environment, and genetics. A recent study also revealed that sleep plays a role. On August 30, the journal JAMA Neurology published a peer revied study that set out to discover the association between sleep duration, cognitive performance, and healthy aging.  


The study has been making headlines for many reasons, one being its size. The team of researchers had one of the largest sample sizes in a study of its kind, with 4417 men and women between the ages of 65 and 85 in the U.S., Canada, Japan, and Australia. This is a significant departure from your typical Alzheimer’s study that consists of less than 100 people in one geometric area.


The researchers found that those who slept less than 6 hours a night had higher levels of a protein called beta-amyloid. This protein accumulates, forming amyloid plaques which is one of the first markers of Alzheimer’s disease. Joseph Winer, a postdoctoral fellow at Stanford University and head of research for the study, told USA Today that this study “suggests there’s something happening in short sleeps that looks like Alzheimer’s disease.”


This doesn’t mean the more you sleep, the less your chance of acquiring Alzheimer’s disease. The same study found that those who slept more than 9 hours a night were also at risk – but for different reasons. Individuals who slept longer than nine hours had an increased body mass index, depressive symptoms, and cognitive decline. This revealed the sleep sweet spot, greater than 6 hours but less than 9, which compliments other sleep research that suggests 8 hours a night is ideal (check out our blog post on why we should sleep 8 hours here).


Winer said that more evidence is needed in younger adults to see if better sleep would also decrease the chance of Alzheimer’s and concluded that “it is important to maintain healthy sleep, especially as you get older.”


Alzheimer’s Disease and Sleep


The unfortunate reality for many older adults is that getting more than 6 hours a night isn’t easy. As we age, our sleep patterns change, and it can be more challenging to sleep. It is even more challenged for those with existing Alzheimer’s, who are more likely to experience sleep troubles or fragmented sleep.


The relationship between the two is complex, but researchers believe that Alzheimer’s causes cellular changes in the brain, which impact a person’s sleep-wake cycle. This results in changes in melatonin production and circadian rhythm. An area of the brain known as the suprachiasmatic nucleus (SCN) acts as an internal clock and responds to light, determining when it is time to be awake and when it’s time to feel sleepy. Scientists suspect that those with Alzheimer’s have damaged SCN cells.


The recent JAMA study shows that individuals who get less than 6 hours of sleep a night have more beta-amyloid. This is also seen in those diagnosed with Alzheimer’s.  Beta-amyloid is linked with brain function. When beta-amyloid stick together, it causes plaques which make it difficult for brain cells to communicate. Some studies have found that excess beta-amyloid is removed from the brain during restorative sleep.


A 2018 study looked at the brains of 20 healthy individuals between 22 and 72 using a PET scan. The scans were taken after a full night's sleep and again after 31 hours of sleep deprivation. Upon reviewing the scans, the researchers found that beta-amyloid levels were 5% higher following a night of sleep deprivation. Further, these changes occurred specifically in the hippocampus and thalamus, an area prone to Alzheimer-related damage. At the time of the study, the researchers suggested that a lack of sleep may contribute to Alzheimer’s.


In addition to making it more difficult for individuals to sleep, Alzheimer’s can make some individuals sleep longer. Long periods of sleep are relatively common in those with dementia and are believed to be caused by the weakening of the brain. The damage caused by Alzheimer’s makes tasks that were once simple much more challenging and mentally fatiguing. As a result, a person can quickly become exhausted and feel they need more sleep, and as the symptoms worsen, they sleep more. Further, many medications that are prescribed to help with these symptoms can cause drowsiness.


Although they may be sleeping more, it isn’t necessarily quality sleep. Many with Alzheimer’s experienced a reduced quality of sleep that can make symptoms worse. When symptoms are severe, it can make it challenging to communicate, and they may be unable to express their difficulties or if something like pain is keeping them up. Research has found that those with Alzheimer’s get less deep sleep and REM (rapid eye movement) sleep, which is critical for memory preservation.


If you have a loved one with Alzheimer’s who has trouble sleeping or getting quality sleep, suggest they sleep on their side rather than their back or stomach. Some preliminary research has found that sleeping position can impact the brain. For example, in 2015, a study performed on rats found that when they slept on their side, their brain was able to remove waste more effectively. An MRI scan showed that the rats who slept on their side cleared out the excess beta-amyloid and metabolic waste products.  


Though further research on humans is needed, this is an exciting discovery. There is no harm in trying, as this is the most common sleeping position. To help them get a good sleep while on their side, ensure they have a supportive pillow that fills the space between their neck and the mattress. An adjustable pillow like a sobakawa pillow will allow you to get the perfect size for their body, ensuring they maintain alignment while on their side. Additionally, a supportive pillow that promotes alignment can help reduce shoulder, neck, or head pain that may be keeping them up at night.  


Caregivers of those with Alzheimer’s can help make other adjustments to manage sleep better.

First, it is best to rule out any other medical conditions that may be impacting their sleep, like sleep apnea or restless leg syndrome. You can also speak with their doctors to see if any of their medications are causing excess drowsiness or making it difficult for them to fall asleep. Sometimes a simple modification in the time the medication is taken can make a big difference.

Once you have spoken with the doctor, you can make some adjustments to their sleep routine and bedroom. For example, a room with a cooler temperature and darkening blinds will help them know when it is time for bed. You can also keep a clock in the room so they can distinguish between day and night. A bedtime routine is also very important. For example, every night, having a glass of warm milk or a cup of sleep tea will help them recognize what time of the day it is.


Your sleep quality is also important, so you should take measures to ensure you get a quality night's rest as well. Caregivers of individuals with Alzheimer's often experience interrupted sleep and reduced quantities of deep and REM sleep. One of the reasons for this is because a caregiver may fear the individual will get up in the night and put themselves in danger. So, they try to sleep with one eye open, ready to hear any sound or indication they are up. If this sounds familiar, you should consider a bed exit pad. This is a wireless pad that will signal when a person has left their bed. It can provide you with an alert, so you know when to get up. This can give you peace of mind, so you aren’t jumping at any noise or sound, unsure if they are up or not.


The recent research on the connection between sleep and Alzheimer’s disease further highlights the importance of sleep. To keep our brains healthy, especially as we age, we must prioritize sleep quality and aim to get a solid 7 to 8 hours each night.   

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