People who experience poor sleep are more likely to possess brains that appear older than their actual years, according to fresh brain imaging research published in the journal eBioMedicine. Previously, inadequate sleep has been connected to dementia, and this latest finding has illuminated the relationship between these two conditions.
Abigail Dove, researcher at the Department of Neurobiology, Care Sciences and Society, Karolinska Institutet said: “Our findings provide evidence that poor sleep may contribute to accelerated brain aging and point to inflammation as one of the underlying mechanisms. Since sleep is modifiable, it may be possible to prevent accelerated brain aging and perhaps even cognitive decline through healthier sleep. The gap between brain age and chronological age widened by about six months for every one-point decrease in healthy sleep score. People with poor sleep had brains that appeared on average one year older than their actual age.”
The research tracked 27,500 middle-aged and older participants from the UK Biobank who underwent MRI scans of their brains.
Scientists then used machine learning to calculate each person’s brain age on a biological basis and contrasted it with their chronological age, which relies on birth date.
The participants were also assigned a sleep quality score based on five different factors:
- Sleep duration per day, including naps
- Insomnia
- Snoring
- Daytime sleepiness
- Chronotype – whether they described themselves as a morning or night person
Those who were early risers, clocking in seven to eight hours of sleep with no reports of insomnia, snoring or daytime sleepiness, scored a perfect five points. For the purposes of the study, the ‘healthy’ sleep group consisted of those scoring four or more points, intermediate was two to three points and poor sleepers scored one point or less.
Both the intermediate and poor sleep groups had a “significantly higher” brain age gap than healthy sleepers. The brain’s age accelerated around six months for every single point lost due to poor sleep habits.
On average, people with an intermediary sleep pattern had a brain age around seven months older than their actual age. Meanwhile, those in the poor sleep group had a brain age almost a full year older than their chronological age.
The study concluded: “Having an older brain age is an early indicator of a departure from optimal brain health. Our findings relating poor sleep to older brain age support the notion that poor sleep may be a risk factor for the development of dementia.
“Future studies are necessary to determine whether improving sleep characteristics can prolong brain and cognitive health.”
The study also discovered that those with mediocre and poor sleep patterns were more likely to be older, male, have a higher BMI and prevalent cardiometabolic diseases. They were also less likely to have a university degree and a healthy lifestyle.
As for why sleep impacts brain age, some theories highlighted by News Medical suggest that the brain’s waste clearance system, which is primarily active during sleep, is negatively impacted by poor sleep. Alternatively, poor sleep could affect cardiovascular health which in turn has a detrimental effect on the brain.