Growing evidence suggests that sleep may play a major role in protecting the brain as we get older.
Scientists have known for years that poor sleep is linked to memory problems, difficulty concentrating, and a higher risk of dementia.
Now, a new study from the University of Arizona suggests that several common sleep habits may be associated with physical signs of brain aging.
The research was published in the journal Alzheimer’s & Dementia and involved more than 23,000 middle-aged and older adults. The study is part of a larger collaboration involving researchers from the University of Arizona, the University of Southern California, and the Zuckerman College of Public Health.
As people age, changes occur naturally in the brain. However, some changes are considered more concerning because they are linked to cognitive decline and dementia. One such change involves the development of white matter lesions. These are small areas of damage that appear in the brain and can be seen on MRI scans.
White matter helps different parts of the brain communicate with each other. When damage accumulates over time, it may interfere with brain function and increase the risk of conditions such as Alzheimer’s disease and other forms of dementia.
The researchers wanted to better understand whether certain sleep behaviors might be connected to these brain changes.
Rather than looking at sleep as a single measure, they examined several different sleep habits separately. This approach allowed them to determine whether specific behaviors were more strongly associated with signs of brain aging.
The study used information from a large biomedical database. Participants completed sleep questionnaires between 2006 and 2010. They answered questions about how long they slept, whether they took daytime naps, how often they experienced sleeplessness, whether they unintentionally fell asleep during the day, and whether they snored.
About nine years later, the same participants underwent MRI brain scans. Researchers then measured the amount of white matter lesions present in their brains and compared those findings with their earlier sleep habits.
At first, all five sleep behaviors appeared to be linked with greater amounts of white matter damage. However, the researchers took an additional step by accounting for other factors that could influence brain health. These included smoking, physical activity levels, high blood pressure, and other blood vessel-related health conditions.
After these adjustments, three sleep behaviors remained significantly associated with larger white matter lesion volumes. These were sleeping outside the recommended range of seven to nine hours per night, frequent daytime napping, and experiencing sleeplessness.
The findings regarding sleep duration were particularly noteworthy. In a follow-up analysis, researchers found that people who reported sleeping less than seven hours each night tended to have more white matter lesions than those who slept within the recommended range.
The researchers did not find strong evidence that longer sleep durations were linked to greater damage, although they noted that more studies involving people who regularly sleep for long periods are needed.
Daytime napping also attracted attention. Naps are often viewed as healthy and can improve alertness, mood, and performance. However, the study found that frequent napping was associated with greater signs of brain aging.
The researchers caution that the questionnaire did not collect details about how long people napped or when those naps occurred. It is possible that short naps and long naps may have different effects on the brain.
Sleeplessness was the third behavior associated with greater white matter damage. Difficulty falling asleep or staying asleep can reduce sleep quality and may interfere with important biological processes that occur during sleep, including waste removal and brain repair.
One encouraging aspect of the findings is that all three sleep habits are potentially modifiable. Unlike some risk factors for dementia, such as age or genetics, sleep patterns can often be improved through lifestyle changes, medical treatment, or better sleep habits.
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Source: University of Arizona.
