HOUSTON — A University of Arizona study published in the journal Alzheimer's & Dementia found that certain sleep behaviors are associated with a marker of brain aging. Researchers identified sleeping outside the recommended seven-to-nine-hour range, frequent daytime napping, and sleeplessness as behaviors linked to greater white matter lesion volume in healthy individuals.
The study utilized existing brain scans and questionnaire responses from over 23,000 middle-aged and older adults from a biobank database. White matter lesions are areas of brain damage that accumulate with age and have a connection to a higher risk of dementias.
Madeline Ally, a graduate researcher at the U of A Department of Psychology and the study's lead author, stated that sleep is a complex behavior. "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. Participants initially completed a questionnaire between 2006 and 2010 to assess sleep duration, daytime napping, sleeplessness, unintentional daytime dozing, and snoring.
Approximately nine years after the initial questionnaire, participants underwent brain MRI scans to measure white matter lesion volumes. The study confirmed these associations even after accounting for factors such as blood vessel health, high blood pressure, smoking, and physical inactivity. Snoring and unintentional daytime dozing were not linked to greater lesion volume after controlling for other variables. Participants who reported sleeping fewer than seven hours per night had increased white matter lesion volume compared to those who slept within the recommended range.
Gene Alexander, a professor in the U of A Department of Psychology and the study's senior author, noted the findings related to sleep duration. "Our findings suggest that having too little sleep may lead to greater white matter lesion volumes in the brain as we age." Alexander said. "We did not 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." Alexander said. He also commented on the potential impact of sleep quality on brain aging. "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.