A large study of more than 23,000 adults suggests that certain sleep habits may be linked to signs of brain aging years later.
Sleep habits may influence how the brain ages over time. A new University of Arizona study suggests that several common sleep patterns are associated with signs of brain aging.
The study, published in the journal Alzheimer’s & Dementia, analyzed existing brain scans and questionnaire data from more than 23,000 middle-aged and older adults in a large biomedical database. The research is part of a wider collaboration involving the U of A Department of Psychology, the Zuckerman College of Public Health and the University of Southern California.
The researchers found that three sleep behaviors were clearly linked to a marker of brain aging in otherwise healthy people: sleeping outside the recommended range of seven to nine hours, frequent daytime napping, and sleeplessness. Each was associated with a larger volume of white matter lesions, which are areas of brain damage that can build up with age and are connected to a greater risk of dementia, including Alzheimer’s disease.
Madeline Ally, the study’s lead author and a graduate researcher at the Department of Psychology, said sleep is often examined as a single overall measure instead of as a set of separate behaviors and patterns. That approach can make it harder to see how specific aspects of sleep relate to brain aging.
“Sleep is a universal but complex behavior, and there is still much to learn about how different aspects of sleep relate to brain health,” Ally said.
Sleep habits leave brain clues
Participants first answered a questionnaire from 2006 to 2010 about five sleep behaviors: how long they slept, whether they napped during the day, whether they experienced sleeplessness, whether they unintentionally dozed during the day and whether they snored. About nine years later, those same participants received brain MRI scans, which the researchers used to measure the volume of white matter lesions. The study was conducted in collaboration with David Raichlen, the lead collaborator at the University of Southern California, and a professor of human and evolutionary biology.
At first, all five sleep behaviors were linked to greater lesion volume. After the researchers adjusted for blood vessel health and lifestyle factors that can also shape brain health, including high blood pressure, smoking, and physical inactivity, three behaviors remained significant: sleeping outside the recommended range, frequent daytime napping, and greater sleeplessness. Snoring and unintentional daytime dozing no longer stood out.
Napping remains more complex
The daytime napping results were especially notable because other research suggests that short naps can support alertness and cognition. Gene Alexander, the study’s senior author and a professor in the Department of Psychology, said the questionnaire did not include details about how long individual naps lasted or when they occurred. Future studies will need to examine whether brief, occasional naps affect the brain differently over time than longer or more frequent naps.
In a follow-up analysis, the researchers examined sleep duration more closely. They found that participants who slept fewer than seven hours a night had higher lesion volume than those who slept within the recommended range.
“Our findings suggest that having too little sleep may lead to greater white matter lesion volumes in the brain as we age,” said Alexander. “We didn’t see greater white matter impacts in people who reported longer sleep durations, but this needs to be followed up in cohorts with more long sleepers.”
Sleep may offer prevention targets
Still, Alexander said the three behaviors have one important feature in common: they can potentially be changed.
“Sleep is one of those potentially modifiable risk factors. If we can improve the quality of our sleep, it may help reduce the impacts of brain aging and maybe even lower the risk for dementias like Alzheimer’s disease,” Alexander said.
Reference: “Associations of sleep behaviors with white matter hyperintensity volume in middle-aged to older adults” by Madeline Ally, Daniel H. Aslan, M. Katherine Sayre, Pradyumna K. Bharadwaj, Silvio Maltagliati, Matthew D. Grilli, Mark H. C. Lai, Rand R. Wilcox, Yann C. Klimentidis, David A. Raichlen and Gene E. Alexander, 5 May 2026, Alzheimer’s & Dementia.
DOI: 10.1002/alz.71457
Supported by the National Institutes of Health (NIH; P30AG072980, P30AG019610, R56AG067200, R01AG064587, and R01AG072445), the state of Arizona and the Arizona Department of Health Services, and the McKnight Brain Research Foundation.
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