Not getting enough sleep could be speeding up your aging and making your brain years older than you actually are.
Physical aging of the brain can cause structural changes like shrinkage and thinning, leading to slower processing, memory issues, and cognitive decline.
It can also result in decreased neurotransmitter production, affecting mood and cognitive flexibility. While some cognitive changes are a normal part of getting older, aging is the largest risk factor for neurodegenerative diseases such as dementia.
According to the National Institute of Health (NIH), up to 35 percent of Americans experience insomnia symptoms, which translates to more than 90 million people.
Looking at the link between poor sleep and brain aging, researchers at Tianjin Medical University General Hospital in China analyzed brain scans and sleep data from over 27,000 middle-aged and older adults in the UK.
Their findings revealed that people with poor sleep habits had brains that appeared older than their actual age.
In particular, those with the worst sleep scored had brains that looked, on average, about a year older than their real age.
Even those with moderately poor sleep showed signs of accelerated brain aging, about seven months ahead of their chronological age.
Poor sleep can physically age your brain by a year, according to a new study. Physical aging of the brain can cause structural changes like shrinkage and thinning, leading to slower processing, memory issues, and cognitive decline (stock image)
The study, published in eBioMedicine, used sophisticated brain imaging and machine learning to estimate ‘brain age’ based on over 1,000 brain features.
A brain that appears older than it should be can be an early sign that brain health may be declining.
‘Having an older brain age is an early indicator of a departure from optimal brain health,’ the researchers noted. Their findings align with earlier studies linking poor sleep to cognitive decline and dementia.
Instead of focusing on just one aspect of sleep, the researchers created a sleep health score using five key indicators: Being a morning person rather than a night owl, getting the recommended seven to eight hours of sleep per night, rarely experiencing insomnia, not snoring and avoiding excessive daytime sleepiness.
Only about 41 percent of participants had what was considered healthy sleep (scoring 4 or 5 out of 5). The majority fell into the moderate category, while around three percent had poor sleep habits.
The data showed that for each one-point drop in the sleep score, brain age increased by roughly six months.
Of the five factors, being a night owl, sleeping too little or too much, and snoring had the strongest links to older-looking brains.
The effect of poor sleep on brain aging was more pronounced in men than in women.
For men, each drop in the sleep score translated to a brain that appeared about 2.5 months older. For women, the link was weaker and not statistically significant.
A graph showing the association between chronic low-grade inflammation in the body and a the brain age gap (a person’s predicted brain age estimated from imaging or other tests, and their actual chronological age
Genetics didn’t seem to change this pattern either. Whether or not someone carried the APOE ε4 gene – a known Alzheimer’s risk factor – the relationship between sleep and brain age held steady.
The study also explored the role of chronic, low-grade inflammation. Using four blood markers, researchers found that higher inflammation scores were associated with faster brain aging. Inflammation explained about 10 percent of the link between poor sleep and older-looking brains.
Sleep problems are known to trigger inflammation, which in turn can damage blood vessels in the brain, contribute to the build-up of abnormal proteins, and cause neuron loss.
The participants were, on average, 55 years old when the study began, and brain scans were done about nine years later.
None had dementia or other major neurological issues at the start.
From the results, the researchers observed evidence suggesting that poor sleep isn’t just a symptom or consequence of brain aging, but might actually contribute to the aging process itself.
It challenges the old idea that brain aging simply causes sleep disturbances, suggesting a two-way relationship or causal effect from sleep to brain health.
Previous research has linked specific sleep problems to measurable changes in the brain, such as reduced hippocampal volume, thinning of the cortex, and damage to white matter. Brain age offers a single measure that captures many of these changes together.
The authors say that some limitations to the study should be noted.
The data came from the UK Biobank, a large health database that includes hundreds of thousands of participants.
While the large sample gives the study strong statistical power, the Biobank population is generally healthier and more educated than the general public; so the true effects of poor sleep might be even more significant in the broader population.
The sleep data was also self-reported, which could introduce some inaccuracies, especially around things like snoring (people living alone may not notice) or differences in sleep between weekdays and weekends (known as social jetlag).
Because of the study’s design, researchers can’t say for certain that poor sleep causes brain aging, only that there’s a strong association. Future long-term studies will help determine whether improving sleep can actually slow brain aging.
Almost 60 percent of people in the study had less-than-ideal sleep, suggesting that many could benefit from changes to their sleep habits.
The five components of healthy sleep provide practical goals: go to bed earlier, aim for seven to eight hours of sleep, treat insomnia and snoring, and avoid daytime sleepiness.
The connection between sleep and brain health held true across various lifestyles, even after adjusting for physical activity, smoking, alcohol use, and medical conditions. This reinforces the idea that sleep is a key modifiable factor – alongside exercise, diet, and mental stimulation – that could help protect brain health as we age.
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