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Trouble sleeping? It could be affecting your brain, study finds

Restless nights might make your brain age faster than the rest of your body

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Mark Huffman
Reporter

Mark Huffman has covered consumer issues since 2004, with a special focus on protecting and empowering older adults. A former news correspondent for the Associated Press Radio Network, Westwood One, and ConsumerAffairs, Mark brings decades of journalistic experience to RetirementLiving.com. He is passionate about giving consumers a voice and helping them make informed decisions. Mark has also created educational content, including Senior Scam Alert, a video resource designed to help seniors recognize and avoid fraud. He holds a B.A. from the University of Kentucky and lives with his family in Richmond, Virginia.
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Key Insights

  • Poor sleep may accelerate brain aging by as much as one year, according to a major study from Karolinska Institutet.
  • Each 1-point drop in healthy sleep score was linked to a six-month widening gap between brain and chronological age.
  • Low-grade inflammation may explain part of the link — and improving sleep could help slow cognitive decline.

A restless night could do more than leave you groggy — it might actually make your brain appear older than it is. 

A large-scale brain imaging study from Sweden’s Karolinska Institutet, published in eBioMedicine, found that people who sleep poorly have brains that appear older than their chronological age.

The study, led by Dr. Abigail Dove of the Department of Neurobiology, Care Sciences and Society, examined data from thousands of participants to measure the “brain age gap” — the difference between a person’s biological brain age and their actual age.

“The gap between brain age and chronological age widened by about six months for every 1-point decrease in healthy sleep score,” Dove explained. “On average, people with poor sleep had brains that looked one year older than their actual age.”

Inflammation: A clue to the connection

Researchers also explored how inflammation in the body might contribute to this accelerated brain aging. They found that low-grade, systemic inflammation accounted for just over 10% of the association between poor sleep and older-appearing brains.

“Our findings provide evidence that poor sleep may contribute to accelerated brain ageing and point to inflammation as one of the underlying mechanisms,” Dove said. “Since sleep is modifiable, it may be possible to prevent accelerated brain ageing — and perhaps even cognitive decline — through healthier sleep.”

Scientists also suggested several other pathways that could explain the relationship:

  • Brain waste clearance: Poor sleep may impair the brain’s glymphatic system, which helps clear out toxins and waste products during deep sleep.
  • Cardiovascular effects: Sleep deprivation negatively affects heart and vascular health, which can, in turn, impact brain function and structure.

The research team noted a few limitations. Participants were drawn from the UK Biobank, a generally healthier population than the broader UK public, which could limit how widely the findings apply. The study also relied on self-reported sleep quality, which may not capture objective sleep patterns.

Why it matters

While the idea of “brain aging” might sound abstract, the findings carry a simple, practical message: improving sleep could protect long-term brain health. 

Establishing consistent bedtimes, limiting screen use before bed, and maintaining a cool, dark sleep environment are small but meaningful ways to boost your sleep quality — and potentially, keep your brain younger for longer.

The research was conducted in collaboration with scientists from the Swedish School of Sport and Health Sciences, Tianjin Medical University, and Sichuan University, with support from the Alzheimer’s Foundation, the Dementia Foundation, the Swedish Research Council, and others.