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Why Are Sleep Disturbances So Common in Dementia?

Sleep cycle and sleep hygiene issues are often the problem.

Sleep disturbances are incredibly common in dementia. If your loved one is having trouble falling asleep, waking up in the middle of the night and wandering around, or sleeping in the middle of the day, the question to be answered is why these sleep disruptions are occurring. Once we understand why they are occurring, we can work on improving the situations. In this post, we will consider sleep disruption caused by sleep cycle and sleep hygiene issues; in the next blog we will consider sleep disorders.

Sleep is governed by two main drives: sleep pressure and circadian rhythm

Two processes work together to determine when we are asleep and awake:

  • Sleep pressure (also called sleep debt) builds up while we are awake; the longer we are awake, the greater the pressure we feel to sleep. Sleep pressure is related to the accumulation of certain chemicals in the brain, whose levels return to normal when we sleep.
  • Circadian rhythm governs our normal, daily patterns of sleep and wakefulness; it is why we may wake up before the alarm goes off and why we suffer from jet lag. Our circadian rhythm is set by the light that we see during the day, which triggers the release of melatonin hours later. Melatonin is a hormone that our body produces that makes us sleepy.

Sleep disturbances may be due to activities in bed, getting into a bad cycle, or trying to sleep too much

More than ten percent of people either experience difficulty falling asleep (insomnia) or another sleep problem. Although sleep problems may be due to a medical disorder, more often they are related to poor sleep habits.

If your loved one spends many hours in bed doing wakeful activities, they may find it difficult to sleep in that bed when they wish to. The feeling of being in bed should be a signal to the body that it is time to go to sleep. It is best to use the bed only for sleeping and sexual activity, although many people do just fine if they spend a short amount of time reading or watching television in bed in preparation for sleep. If, however, one spends hours in bed talking on the phone, eating meals, or doing other activities, the wrong signals are sent to the body about what the bed is for.

Another common problem is when we get into a bad sleep cycle. This problem generally happens when one repeatedly stays up too late at night or sleeps in too long in the morning. Staying up late usually occurs because of some activity one is engaged in, such as going out with friends, watching television, or reading far into the night. Sleeping too long in the morning may simply be our attempt to compensate for going to bed late. But it can also be due to an attempt to sleep too many hours. Most people need about eight hours of sleep each night, with the average range between seven and nine. Many people think that they need more sleep as they get older, but that actually isn’t true. On average, older adults need the same amount of sleep as when they were younger—or maybe even 30 minutes less! So, the average sleep for older adults is between six-and-a-half and nine hours.

Sometimes these difficulties can be extreme. We recently saw an individual with dementia whose family asked us to prescribe sleeping pills because they were up every night at 3 a.m. in the morning. It turned out, however, the problem was that they were going to bed at 7 p.m., so that by 3 a.m. in the morning they had already slept eight hours!

Brief naps are fine as part of total sleep

What’s wrong with taking a nap in the afternoon? Absolutely nothing! Even a brief nap can relieve the sleep pressure that builds up during the day. In addition, afternoon naps are actually built into our circadian rhythm. That’s why in countries like Spain and Italy it is common to take a siesta in the afternoon. The two important things to remember about naps is that they should be brief—never longer than an hour—and that they count as part of total sleep hours. So, if your loved one was sleeping eight hours each night and feeling rested when they were working and, now that they’re retired, they are napping for an hour each day—that’s fine—but they should reduce their nighttime sleeping to seven hours so they don’t try to sleep too much.

© Andrew E. Budson, M.D., 2020, all rights reserved.


Budson AE, O’Connor MK. Seven Steps to Managing Your Memory: What’s Normal, What’s Not, and What to Do About It, New York: Oxford University Press, 2017.

Budson AE, Solomon PR. Memory Loss, Alzheimer’s Disease, & Dementia: A Practical Guide for Clinicians, 2nd Edition, Philadelphia: Elsevier Inc., 2016.

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