What to know about Alzheimer's and sleep

Share on Pinterest

People with Alzheimer’s may not sleep well at night but sleep excessively during the day. Experts do not fully understand why Alzheimer’s affects sleep. The relationship between the two is complex, and sleep disturbances may precede the cognitive decline that occurs in people with Alzheimer’s.

Circadian rhythm

Researchers think that Alzheimer’s causes cellular changes in the brain, disrupting the sleep-wake cycle, which is a type of circadian rhythm. Changes in the production of melatonin, the sleep hormone, also contribute.

The suprachiasmatic nucleus (SCN) is an area of the brain that serves as an internal body clock. The SCN responds to light cues that help determine when people are awake and alert and when they feel sleepy. Experts believe that individuals with Alzheimer’s disease may have damaged cells in their SCN. This damage affects the activity in this area, leading to difficulty following a typical sleep-wake cycle.

Learn more about circadian rhythms here.

Brain proteins

The sleep changes in people with Alzheimer’s may relate to a protein called beta-amyloid. Beta-amyloid is a waste product that can build up in the fluid between brain cells, or neurons. Doctors link increases in this protein with impaired brain function. If an individual has Alzheimer’s disease, beta-amyloid sticks together and causes amyloid plaques that negatively affect communication between brain cells.

Some studies suggest that when someone sleeps, the brain clears excess beta-amyloid from the brain. Research on mice shows that sleep deprivation causes elevated brain beta-amyloid levels. However, at present, there is a lack of research involving people.

In a 2018 study, researchers looked at the link between beta-amyloid and sleep in human subjects. They used PET scans to look at the brains of 20 participants aged 22–72 years with a good health status.

The researchers took scans after the participants had had a full night’s sleep and after about 31 hours without sleep. They found that beta-amyloid levels in the brain increased by about 5% following sleep deprivation. The changes happened in the thalamus and hippocampus, which are particularly vulnerable to damage from Alzheimer’s disease. A lack of sleep may, therefore, contribute to Alzheimer’s.

Alzheimer’s also involves a brain protein called tau, which helps regulate healthy signaling between neuronal cells. People with Alzheimer’s disease have tangles of tau protein in their brains, indicating damage to nerve cells. As little as 1 night’s sleep deprivation can increase tau levels by as much as 50% in cerebrospinal fluid.

The relationship between beta-amyloid, tau, and Alzheimer’s is complex, and experts understand that high quality sleep allows an individual to clear excess brain proteins. Still, they remain unsure whether sleep disruption prompts Alzheimer’s, aggravates symptoms, and causes disease progression or whether sleep disruption is a consequence of the disease.

People with Alzheimer’s and other forms of dementia often sleep for long periods and may need to sleep during the day.

As Alzheimer’s progresses, it causes an increasing amount of damage to the brain, and the individual becomes weaker. A person may feel exhausted after everyday tasks, such as communicating, eating, or trying to make sense of the world around them. People may sleep more during the day as the symptoms worsen.

Additionally, medications that doctors prescribe to treat Alzheimer’s can contribute to sleepiness. These medications may include antipsychotics, antidepressants, antihistamines, and sleeping pills.

Some of the challenges that Alzheimer’s poses can result in an individual having reduced sleep quality, which may, in turn, worsen other symptoms of Alzheimer’s. For example, a lack of sleep can increase delusions, restlessness, and wandering, making sleeping more challenging.

People with Alzheimer’s may have difficulty communicating to their caregivers that something is wrong. For example, they may be unable to tell someone that they are experiencing pain. In this case, the pain may impair their sleep.

Having sufficient deep sleep and rapid eye movement (REM) sleep is necessary for memory preservation, and memory loss is the leading Alzheimer’s symptom. People with Alzheimer’s progressively experience less deep sleep and REM sleep.

Other potential effects of Alzheimer’s on sleep include decreased physical activity and spending less time in natural sunlight.

People with Alzheimer’s may wish to try sleeping on their side rather than on their back or stomach.

A 2015 study using rats found that sleeping laterally may remove brain waste more effectively. The researchers used dynamic contrast MRI scans to examine how the rats’ brains cleared excess beta-amyloid and other metabolic waste products.

They concluded that body posture while sleeping affected the clearance of damaging brain proteins that could contribute to or cause brain diseases. However, further research is necessary to confirm that this finding is applicable to humans.

Caregivers of people with Alzheimer’s can take steps to help them manage their sleep. These include:

• Identifying any other medical conditions: Caregivers can watch the individual to see whether they have a condition that results in them waking up. For example, sleep apnea causes short pauses in breathing, and restless leg syndrome involves moving or twitching the legs uncontrollably.
• Reviewing their medication: The side effects of some prescription medications that treat Alzheimer’s may contribute to sleepless nights. A doctor can advise on the best time of day to take medications to ease these effects.
• Keeping the time visible: It may be beneficial for the individual to be able to see a clock that distinguishes between nighttime and daytime.
• Talking to them: If the individual gets up in the night, a caregiver can talk to them to try to find out why. It is then best to keep the person relaxed and prepare them for returning to sleep with low lighting and relaxing music that they enjoy.
• Using a bed exit pad: These wireless pads signal if the individual wanders from their bed during the night. Once a caregiver receives the alert, they can assist the individual in getting back into bed as soon as possible.
• Establishing a routine: Keeping to the same bedtime and wake time each day and putting a routine in place — such as a relaxing bath or a hot, milky drink before bed — can help the individual recognize the time of day.

Alzheimer’s disease is the sixth leading cause of death in the United States, contributing to more deaths than both breast cancer and prostate cancer together.

Alzheimer’s is a progressive condition, and a person’s life expectancy depends on various factors. Following an Alzheimer’s diagnosis, the average life expectancy is 4–8 years, but an individual may live for longer.

Various treatments can address Alzheimer’s symptoms and help an individual manage their sleeping problems. The individual with Alzheimer’s and their family members or caregivers will need medical and emotional support to help them navigate the condition.

Learn more about the stages of Alzheimer’s here.

Alzheimer’s disease is a form of dementia that can lead to sleeping issues. Experts also think that sleeping issues could contribute to an individual developing Alzheimer’s.

The relationship between Alzheimer’s and sleep issues is complex and may encompass cellular changes in the brain that upset the typical circadian rhythm. Sleep issues may also involve changes in melatonin production and a buildup of the proteins beta-amyloid and tau in the brain.

Although sleep issues can be challenging to manage, caregivers can take various steps to help an individual with Alzheimer’s sleep better. These include putting a nighttime routine in place and discussing with a doctor the best time of day to take medications.