Six Hours of Sleep or Less in Your 50s and Dementia Risk: What a 25-Year Study Found
Sleep & NighttimeArticleA British study that followed nearly 8,000 adults for 25 years found that sleeping six hours or less at age 50 or 60 was linked to a higher chance of dementia later, and persistent short sleep across midlife carried about 30% higher risk. It shows a link, not proof that short sleep causes dementia, but it's one more reason to take midlife insomnia seriously.
Poor sleep is a feature of dementia, but researchers have long wondered whether short sleep earlier in life raises the risk.1 The Whitehall II study in Britain offers one of the longest looks at that question.
What the study did
Researchers followed 7,959 adults for 25 years, comparing sleep duration at ages 50, 60 and 70 with later dementia. 521 people developed dementia.1
What it found
Compared with people sleeping about 7 hours:1
| Sleep of 6 hours or less at… | Dementia risk |
|---|---|
| Age 50 | About 22% higher |
| Age 60 | About 37% higher |
| Age 70 | Possibly higher, but less certain |
People who consistently slept 6 hours or less at 50, 60 and 70 had about 30% higher risk than those who consistently slept about 7 hours.1 This held after accounting for social, behavioral, heart and metabolic, and mental health factors.1
What it doesn’t prove
This was an observational study. It shows short sleep in midlife is linked to later dementia, not that it causes it.1 Early brain changes, other health conditions or factors the researchers couldn’t measure might explain part of the link.
What this means for you
- Treat ongoing insomnia rather than accepting it as part of midlife. Our guides to CBT-I and CBT for menopause insomnia explain the first-line treatment.
- Check for sleep apnea if you snore, wake unrefreshed or have morning headaches. See sleep apnea without snoring in women.
- Be cautious with sleep aids. See PM sleep aids after 50 and benzodiazepines after 65.
- Don’t panic about a bad week. The study looked at typical sleep over years.
Try: “I’ve been sleeping five or six hours a night for years. Could we look at why, and would CBT-I help me get closer to seven?”
Did I Do That in My Sleep? includes a 14-Night Lights-Out Record and a Visit Brief. Use them to log how long you actually sleep each night before your appointment. See the book.
This article is for general educational purposes only and is not medical advice. It isn't a substitute for diagnosis or treatment from a qualified healthcare professional who knows your health history. Please don't start sleeping pills or supplements without talking to your clinician, since some sleep medicines carry their own risks for older adults. New memory problems, confusion, or loud snoring with pauses in breathing should be evaluated. If you think you may be having a medical emergency, call 911 or your local emergency number right away. This article discusses observational research. Girl Playbook does not endorse any specific product, test, or provider.
Girl Playbook sells this book. It provides education and worksheets, not individualized medical care.
Sources
The research behind this article, in the order it’s cited. How we source our articles.
- Nature Communications (full text via PubMed Central), 2021Association of sleep duration in middle and old age with incidence of dementia (opens in a new tab)abcdef
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