People with dementia, especially those in the later stages, can often spend a lot of time sleeping. This can sometimes be worrying for carers, friends and family. Find out why a person with dementia might sleep more than an average person of their age.

It is quite common for a person with dementia, especially in the later stages, to spend a lot of their time sleeping – both during the day and night. This can sometimes be distressing for the person’s family and friends, as they may worry that something is wrong. 

Sleeping more and more is a common feature of later-stage dementia. As the disease progresses, the damage to a person’s brain becomes more extensive and they gradually become weaker and frailer over time. As a result, a person with dementia may find it quite exhausting to do relatively simple tasks like communicating, eating or trying to understand what is going on around them. This can make the person sleep more during the day as their symptoms become more severe. 

Some medications may contribute to sleepiness. These include some antipsychotics, antidepressants, antihistamines and of course sleeping pills. Sleeping disorders unrelated to dementia, such as having breathing that occasionally stops during sleep (known as ‘apnoea’), can also contribute to sleeping for longer. 

What should I do if a person with dementia is sleeping a lot? 

If the person is in the later stages of dementia and they have gradually started sleeping more and more, it is likely to be due to the dementia progressing. However, if the excessive sleeping has started more suddenly, or the person doesn’t seem well in other ways, it may have another cause.  

If this is the case you should speak to the GP, to rule out any infections or conditions that could be affecting the person's sleep. It may also be worth asking for a medication review with the GP or speaking to a pharmacist as medication can cause a range of side effects. 

Providing the person doesn’t appear to be uncomfortable or distressed, then sleeping more during the day isn’t normally a reason to be worried. However, if a person is lying down in bed and asleep for most of the time they will need to be looked after to make sure they don’t develop any physical health problems. This sort of care is normally done by a health or social care professional in a care home or hospice. If the person is still living at home though, then it’s important to get advice from your GP or nurse on how best to do this.

Why does dementia affect sleep? 

Problems with sleep are very common for people with dementia. They can include: 

• sleeping during the day and being awake and restless during the night 
• becoming disorientated in the dark if they wake up to use the toilet 
• waking up more often and staying awake longer during the night 
• getting up in the early hours and thinking it’s day time or time to go to work (disorientation in time) 
• not being able to tell the difference between night and day. 

Nobody completely understands why dementia affects sleeping patterns. For some people, it may be that their internal ‘biological clock’, which judges what time it is, becomes damaged so the person starts to feel sleepy at the wrong time of day.

There are also other parts of the brain which control whether or not we stay awake, and these may also not work properly if they become damaged.   Sometimes a person with dementia might completely reverse their normal sleep pattern, staying up all night and then sleeping all day. 

Does quality of sleep matter for people with dementia? 

The quality of a person's sleep gradually deteriorates as they get older. They tend to get less deep or ‘slow-wave’ sleep, which helps to keep the brain healthy and refreshed. Even though a person with dementia may end up sleeping more than a typical person of their age – even as much as 14–15 hours a day – it is unlikely to all be good quality sleep. 

Sleeping a lot can also be influenced by people’s sleeping patterns before they had dementia, as some people need more sleep than others. 

Sleep for people who have dementia with Lewy bodies and Parkinson’s disease 

The type of dementia you have can affect your sleep. People who have dementia caused by Lewy body disease, such as Parkinsons’ disease (PD) or dementia with Lewy bodies (DLB) are often sleepy by day but have very restless and disturbed nights. They can suffer from confusion, nightmares and hallucinations. Insomnia, sleep apnoea (breathing difficulties) and restless legs are common symptoms. 

A person affected with these types of dementia may often unknowingly ‘act’ out their dreams by shouting and moving around in bed. They can even cause injury to themselves and/or their sleeping partner. This is called rapid eye movement (REM) sleep behaviour disorder or RBD, and tends to happen from the earliest stages of the disease onwards.

This can be exhausting and often leaves the person feeling like they haven’t slept at all, so they are very tired and sleepy during the day.

It can be hard to stay awake during the day after a poor night’s sleep but, if possible, it’s best to try to limit sleep during the day to small bursts or ‘catnaps’. Otherwise the person’s body clock can become very confused and this makes sleeping well during the night even harder.