Many people struggle to get a good night’s sleep during midlife, including those raising young children, dealing with work-related stress and using technology more frequently throughout their lives. However, this might have more long-lasting effects than you think.
A recent study released in October 2024 showed that reduced brain volume, which is associated with normal aging and neurodegenerative conditions like dementia, is correlated with poor sleep in midlife and is apparent in brain scans even a decade later. Let’s take a closer look at the study and why now is the time to prioritize getting better sleep for the sake of your future brain.
Poor sleep and brain aging
The study, published in Neurology, involved about 600 adults who averaged 40 years of age. They were questioned initially, followed by a follow-up questionnaire five years later and then a brain scan 10 years later after the follow-up. The correlation that emerged was based on machine learning’s estimate of brain age based on changes in brain structure: when a person’s brain was scanned, the machine could generate an estimate of brain age.
70% of participants reported no more than one poor sleep characteristic at the start of the study. Compared to this group, the folks who experienced moderate sleep challenges had brains that were, on average, 1.6 years older; the latter group constituted 22% of the sample. The 8% of people who reported having the most difficulty sleeping in midlife had brains that averaged 2.6 years older. The study shows a strong correlation, not causation, but these results emerge in an environment where sleep is being studied as a variable in brain health.
According to one of the authors, Clémence Cavaillès of the University of California in San Francisco Department of Psychiatry and Behavioral Sciences, “While we can’t say that poor sleep causes dementia, earlier research has established an association. Even if the cause of dementia is unrelated to sleep, it’s possible that poor sleep may advance or exacerbate cognitive symptoms.”
It’s also important to show that the issues that produced the correlation were difficulty getting to sleep, difficulty staying asleep and waking up too early, not overall amount of sleep. The correlation didn’t emerge, for instance, just because someone slept less or more. The study suggests that sleep quality, rather than just total sleep duration, plays a significant role in brain health without ill effects.
Scientists continue to research whether improving sleep in midlife could help reduce risk factors for dementia and slow cognitive decline. Difficulty falling asleep and waking up too early are symptoms that may be worth your while to change, both because of the emerging research and because prioritizing good sleep can also improve your quality of life right now.
