A new study found that sleep difficulties may be linked to a more rapid decline in brain volume.
In the study, published yesterday in the online issue of Neurology, European researchers assessed the sleep habits of 147 adults between the ages of 20 and 84 and took two MRI scans three and a half years apart. They found that 35 percent of the group that had poor sleep quality also had a reduced volume within the major brain regions of frontal, temporal, and parietal areas, during the study. Those over the age of 60 had the most pronounced results.
This finding doesn't definitively mean sleep deprivation or having trouble falling asleep causes brains to shrink, though. It could be the other way around, according to study author Claire E. Sexton, who is out of the University of Oxford.
Sexton wrote by email that it's possible that "greater rates of decline in brain volumes may make it more difficult to get a good night's sleep." If true, that would suggest those in the study who had difficulty sleeping already had shrinking brains for whatever reason. Regardless of what caused what, Sexton doesn't think everyone with difficulty sleeping should now rush out to get brain MRIs.
"I would not say that our findings should be a cause for concern for people," wrote Sexton by email. "Previous studies have linked several factors with an increased rate of decline in brain volumes, such as physical inactivity, high blood pressure, and high cholesterol. Our study indicates that sleep is also an important factor, and since there are many effective treatments for sleep disorders, it could be an exciting avenue through which to promote brain health."
Past studies, that have linked poor sleep habits to everything from weak immune systems to dementia, make this finding not too shocking to those in the medical world. It seemed to naturally follow from existing research. But the sleep-deprived need not worry quite yet that their brains are declining since the study did not directly show a cause and effect between sleep habits and brain size.