Your Sleep Habits Could Be Aging Your Brain, New Study Suggests

Most of us know what a poor night’s sleep feels like the next day. You may wake up groggy, yawn through the afternoon and find it harder to think clearly or get things done. But poor sleep may leave clues that last beyond the following morning. A new study found that short sleep, frequent daytime napping and trouble sleeping were linked to a greater volume of white matter lesions, a possible sign of damage to the brain’s small blood vessels.

Read: Brain Fog After 50? What’s Normal and What’s Not

Read: A gym for your brain? Yes, and with proven health benefits

What They Found

White matter hyperintensities, or WMH, are bright spots seen on certain brain MRI scans. Small amounts become more common with age and do not necessarily mean something is wrong, but a greater volume may signal damage to the brain’s small blood vessels. Greater WMH volume has also been linked to a higher risk of stroke, problems with memory and thinking and dementia.

The study, published in Alzheimer’s & Dementia, examined whether common sleep habits were related to the amount of WMH found on brain scans years later. Researchers analyzed data from 23,377 generally healthy participants in the UK Biobank, a long-running research project in the United Kingdom.

At the start of the study, participants answered questions about five sleep behaviors. About nine years later, they underwent brain MRI scans to measure WMH volume.

The researchers looked at:

• Sleep duration: total sleep over 24 hours, including naps, with seven to nine hours considered the recommended range.
• Daytime napping: napping sometimes or usually.
• Sleeplessness: sometimes or usually having trouble falling asleep or waking during the night.
• Snoring: complaints reported by a partner, relative or close friend.
• Daytime dozing: unintentionally falling asleep while working, reading, driving or doing another activity.

At first, all five behaviors were linked to greater WMH volume, but only three stood out after the researchers accounted for other factors that could affect brain health: sleeping outside the seven-to-nine-hour range, napping sometimes or usually and experiencing sleeplessness sometimes or usually.

Of the three, napping showed the strongest link to WMH. However, the authors cautioned that the napping finding does not mean naps cause brain damage. A brief occasional nap may differ from longer or more frequent daytime sleep, and napping may reflect poor nighttime sleep, an underlying health condition or early brain changes.

When the three sleep habits were analyzed together, each remained tied to WMH volume, suggesting that each may have its own link to brain health.

The results were also similar after the researchers excluded shift workers and when the analysis focused only on adults aged 60 and older.

A closer look at sleep duration showed that short sleep drove the finding. People who slept six hours or less had greater WMH volume than those who slept seven to nine hours. No clear increase was found among those who slept nine hours or more.

“Our findings suggest that having too little sleep may lead to greater white matter lesion volumes in the brain as we age,” said Gene Alexander, the study’s senior author and a professor in the Department of Psychology at the University of Arizona, in a university news release.

A 2021 study of nearly 8,000 adults found that people who regularly slept six hours or less in their 50s and 60s had about a 30% higher risk of dementia than those who slept seven hours.

A study from ‘nature communications’ journal

How Sleep May Be Connected to Dementia

A growing number of studies have linked poor sleep to dementia, though researchers are still trying to determine whether sleep problems contribute to brain changes, develop as an early sign of them or both.

One study that followed 826 older adults for nearly two decades found that regularly sleeping fewer than seven hours a night was linked to a higher risk of cognitive decline. Those whose sleep duration varied the most from year to year had more than three times the risk.

Dr. Jeffrey Iliff, a professor at the University of Washington School of Medicine and a co-author of the study, said evidence suggests that sleep in midlife may shape the risk of cognitive decline later on. “So, people should focus on good sleep now as a priority, the same way they might focus on maintaining a healthy diet or exercising regularly.”

A 2021 study of nearly 8,000 adults found that people who regularly slept six hours or less in their 50s and 60s had about a 30% higher risk of dementia than those who slept seven hours.

A 2019 study also found that older adults with less slow-wave sleep had higher levels of tau in the brain. Slow-wave sleep is the deep stage that helps the brain process memories and the body recover. Tau is a protein that builds up abnormally in Alzheimer’s disease and can damage brain cells.

Poor sleep may affect brain health in several ways. It can contribute to high blood pressure, diabetes and inflammation, which can damage blood vessels over time. Sleep also supports memory and may help the brain clear away waste products.

The relationship may also work in reverse. Early brain changes can disrupt normal sleep patterns, creating a cycle in which poor sleep affects the brain while those brain changes make restful sleep harder to achieve.

Make Sleep a Brain-Health Priority

An occasional restless night or daytime nap is not a reason to worry, as sleep naturally varies. What matters more are patterns over time. Pay attention if you regularly sleep fewer than seven hours, struggle to fall or stay asleep or need more frequent daytime naps.

The good news is that sleep habits can often be improved. While sleep may change with age, poor sleep is not something you simply have to accept. Set aside enough time for rest, keep a regular sleep schedule and make sleep a priority rather than something you fit in around everything else.