Nappers of the world rejoice! Your habit may mean you have a bigger brain. A new study from University College London has found regular daytime napping may help preserve brain health by slowing the rate of brain shrinkage during the aging process.
UCL scientists also partnered with colleagues at the University of the Republic in Uruguay and published their findings in the journal Sleep Health. They analyzed data from a large pool of people aged 40 to 69 and they found a causal link between frequent napping and larger brain volume. That’s thought to be a marker of good brain health because of its link to a lower risk of dementia and other brain-related issues.
"Our findings suggest that, for some people, short daytime naps may be a part of the puzzle that could help preserve the health of the brain as we get older," said study author Dr. Victoria Garfield.
Other studies have shown the cognitive benefits of napping. In one, people who had a short nap performed better on cognitive tests after they awoke than those who did not nap. This study was designed to determine if there was a relationship between daytime napping and brain health.
The study was conducted by using a technique called the Mendelian randomization. Researchers used a pool of 378,932 participants in the UK Biobank study and compared the group that was more genetically “programmed” to nap with those unlikely to nap. That was done by segmenting out the people with the 97 snippets of DNA consistent with nappers.
The people predetermined to nap had a larger brain volume than the others. Researchers estimated the size difference equated to between 2.6 and 6.5 years of aging.
"This is the first study to attempt to untangle the causal relationship between habitual daytime napping and cognitive and structural brain outcomes," said researcher Valentina Paz. "By looking at genes set at birth, Mendelian randomization avoids confounding factors occurring throughout life that may influence associations between napping and health outcomes. Our study points to a causal link between habitual napping and larger total brain volume."
Researchers did not have information on nap duration but previous studies suggest naps that are 30 minutes or less generally provide the best short-term cognitive benefits. And naps taken earlier in the day are less likely to disturb a person’s night-time sleep.
"I hope studies such as this one showing the health benefits of short naps can help to reduce any stigma that still exists around daytime napping," Dr. Garfield added.