Why Do People With Dementia Sleep So Much?

Sleeping more and more is common as dementia progresses, but sudden sleepiness can signal an infection, medicine side effect or other treatable problem. Here's what's typical, what's not, and how to help.

By Jim Pavlish, Editor · Last updated: October 28, 2026 · Editorial policy

Many families notice that a parent or spouse with dementia is sleeping much more than before: long naps, dozing in the chair most of the afternoon, or hardly being awake at all in the later stages. It's natural to worry that something is wrong. Sometimes it is just the disease progressing. Sometimes it's a sign of a problem that can be treated.

This page is general information, not medical advice. If someone suddenly becomes very hard to wake, is confused in a new way, has a fever, trouble breathing, or isn't eating or drinking, call their doctor right away, or 911 in an emergency.

Is it normal?

Sleeping more is common as dementia advances. The Alzheimer's Society says people in the later stages often sleep a lot during both day and night, sometimes as much as 14 to 15 hours a day. As long as the person seems comfortable and not distressed, a gradual increase in sleep isn't usually a cause for alarm in late-stage dementia.

Extra sleep can show up earlier, too. A study of 1,401 older adults in Chicago, published in Alzheimer's & Dementia in 2022, tracked daytime napping with wrist activity monitors for up to 14 years. Naps tended to get longer and more frequent with age, and they increased much faster once people developed mild cognitive impairment or Alzheimer's. Older adults who napped at least once a day, or for more than an hour a day, were about 40% more likely to develop Alzheimer's later. The researchers believe the relationship may run both ways: brain changes may cause more napping, and long napping may be an early sign of those changes. It doesn't mean napping causes dementia.

Why dementia causes more sleep

• Brain damage affects the body clock. Dementia can damage the parts of the brain that set our 24-hour rhythm and keep us awake, so the person feels sleepy at the wrong times.
• Everyday tasks are exhausting. Following a conversation, eating or making sense of what's going on takes much more effort as the brain changes. The person may tire quickly and need to rest.
• Poor sleep at night. People with dementia often wake often at night or are up and restless in the early hours, then make up for it during the day. Some completely flip day and night. See Sleep Problems in Dementia and Sundowning.
• Frailty. In the late stage, the body gradually weakens, and sleeping more is part of that.
• Type of dementia. People with Lewy Body Dementia or Parkinson's Disease Dementia are often very sleepy during the day, partly because their nights are disturbed by vivid dreams, acting out dreams, restless legs or breathing problems.

Other causes to check

Not all sleepiness is from dementia itself. Ask the doctor about:

• Medicines. Some antipsychotics, antidepressants, antihistamines (including some over-the-counter sleep aids and allergy pills), sleeping pills, anxiety medicines and pain medicines can cause drowsiness. A medicine review with the doctor or pharmacist is a good idea. See Medications That Can Affect Memory.
• Infections. A urinary tract infection, pneumonia or other infection can make an older person suddenly sleepy and confused. This is delirium, and it's a medical problem that needs prompt attention.
• Sleep apnea. Loud snoring, pauses in breathing or gasping at night can mean sleep apnea, which is treatable.
• Depression. Withdrawal, low mood and sleeping a lot can be signs of depression.
• Dehydration, pain, low thyroid, low blood sugar or other health changes.

A good rule: a slow change over weeks or months is more likely to be the disease. A sudden change over hours or days, or sleepiness with other signs of illness, needs a doctor.

How to help

If the extra sleep seems to be disturbing nights or the person seems bored or under-stimulated, the National Institute on Aging and the Alzheimer's Association suggest:

• Keep a regular schedule for waking up, meals and going to bed.
• Get daylight. Open the curtains, sit by a window, or go outside in the morning.
• Plan gentle activity during the day, such as a short walk, music, or simple chores. See Activities for People with Dementia.
• Keep naps short and early, if possible, rather than long late-afternoon sleeps.
• Limit caffeine and alcohol, especially later in the day.
• Make evenings calm, with dim lights, less noise and a familiar bedtime routine.

Non-drug approaches are generally preferred. Sleeping pills can increase confusion and the risk of falls in people with dementia, so any sleep medicine should be discussed carefully with the doctor.

In the late stage

If someone in Late-Stage Dementia dementia is sleeping most of the time, the goals often shift to comfort. Make sure they get regular help with drinking and eating as able, changing position to protect their skin, mouth care and toileting. Ask the doctor or a nurse how best to do this at home. Increasing sleep, along with eating and drinking less, can also be one sign that the person is nearing the end of life. If you're wondering whether it's time, our guide to Hospice and End-of-Life Care explains palliative care and hospice and how to ask about them.

The bottom line

Sleeping more is common in dementia, especially in the later stages. But sudden sleepiness, or sleepiness with confusion, fever or not eating, can be a sign of infection, a medicine problem or another treatable cause. When in doubt, call the doctor.

Sources

1. Alzheimer's Society (UK): Is it typical for people with dementia to sleep a lot during the day?
2. National Institute on Aging: Managing Sleep Problems in Alzheimer's Disease
3. Alzheimer's & Dementia (Li et al., 2022): Daytime napping and Alzheimer's dementia: A potential bidirectional relationship
4. Alzheimer's Association: Treatments for Sleep Changes

Not medical advice. This article is general information, not a diagnosis or treatment plan for any individual. Talk with a doctor about your situation.

Related articles

• Sleep Problems in Dementia
• Late-Stage Dementia
• Sundowning
• Delirium vs. Dementia
• Medications That Can Affect Memory
• Hospice and End-of-Life Care