Key Points:
- Poor sleep speeds up brain aging and raises dementia risk.
- Sleep habits like duration, insomnia, and snoring strongly affect brain health.
- Good sleep (7–8 hrs, treating issues) helps slow brain aging.
Not getting enough quality sleep may cause the brain to age faster, according to a large study that analyzed data from more than 27,000 adults. Researchers found that poor sleep brain aging were linked to brains that appeared older than their actual age, raising concerns about long-term brain health and the risk of cognitive decline.
The study, published in eBioMedicine, was conducted by researchers at Tianjin Medical University General Hospital in China. It used brain scans, sleep data, and machine learning to calculate “brain age,” a measure based on more than 1,000 structural features of the brain.
Sleep problems affect millions
Sleep disorders are widespread in the United States. The National Institutes of Health estimates that up to 35 percent of Americans—over 90 million people—experience insomnia symptoms. Poor sleep is already associated with higher risks of memory loss, reduced cognitive flexibility, and dementia. This new research suggests that it may also directly accelerate the physical aging of the brain.
“Having an older brain age is an early indicator of a departure from optimal brain health,” the study authors said. They noted that brain aging includes structural changes such as shrinkage and thinning, which can slow information processing and affect memory.
Brain scans reveal aging effect
Participants in the study were, on average, 55 years old when researchers began collecting data. None had dementia or other serious neurological conditions at the start. Over the course of about nine years, their sleep habits and brain scans were analyzed to measure the impact of sleep quality on brain health.
Those with the worst sleep habits had brains that appeared, on average, about one year older than their chronological age. Even people with moderately poor sleep showed signs of poor sleep brain aging, about seven months ahead of their real age.
Researchers created a sleep health score based on five factors: being a morning person, sleeping seven to eight hours per night, rarely experiencing insomnia, not snoring, and avoiding excessive daytime sleepiness. Only 41 percent of participants scored well on this scale. About three percent had poor sleep, while the rest fell into a moderate category.
For each one-point drop in the sleep score, brain age increased by about six months. Of the five factors, being a night owl, sleeping too little or too much, and snoring had the strongest associations with older-looking brains.
The link between poor sleep and brain aging was stronger in men than in women. For men, each drop in the sleep score added an average of 2.5 months to brain age. In women, the connection was weaker and not statistically significant.
Lifestyle changes may reduce risk
The study also found that chronic, low-grade inflammation played a role in the relationship between poor sleep and brain aging. Higher inflammation scores, measured through blood markers, explained about 10 percent of the effect. Sleep problems are known to increase inflammation, which can damage blood vessels, disrupt normal brain proteins, and contribute to neuron loss.
Genetics did not alter the pattern. Whether or not participants carried the APOE ε4 gene, a known Alzheimer’s risk factor, poor sleep still correlated with faster brain aging.
Researchers emphasized that the findings show an association, not direct proof of cause. Because sleep data was self-reported, results may have inaccuracies, particularly for factors like snoring or differences between weekday and weekend sleep. They also noted that the study population, drawn from the UK Biobank, was generally healthier and more educated than the general public, which could mean the real-world effects of poor sleep brain aging are even greater.
Despite these limitations, the results align with previous research linking inadequate sleep to structural changes in the brain, such as reduced hippocampal volume and white matter damage. The findings suggest a two-way relationship, where poor sleep not only reflects brain aging but may also contribute to it.
Nearly 60 percent of participants had less-than-ideal sleep, highlighting the importance of practical steps to improve rest. The researchers said that adopting healthy sleep habits—going to bed earlier, aiming for seven to eight hours per night, addressing insomnia or snoring, and avoiding daytime fatigue—could help slow poor sleep brain aging.
The study reinforces sleep as a key lifestyle factor, alongside exercise, diet, and mental activity, that can help preserve brain health as people age.
