​How this simple afternoon habit can keep the brain sharp

The brain is our everything. Keeping it healthy and sharp is key to having a fulfilled life. But how do you keep your brain sharp? Well, you could be doing that already, unknowingly. Do you enjoy a daytime nap? If your family is annoyed by you being a couch potato, next time, tell them that science approves of it. Yes, that’s right. Daytime nap is linked to larger brain volume.
A study led by researchers at University College London (UCL) and the University of the Republic in Uruguay found that daytime napping may help to preserve brain health by slowing the rate at which our brains shrink as we age. The study is published in the journal . The researchers studied whether there was an association between daytime napping, cognitive function, and brain volume. To understand this, they analysed data from people aged 40 to 69.

Senior author Dr Victoria Garfield (MRC Unit for Lifelong Health & Ageing at UCL) said, “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.” The study found a causal link between habitual napping and larger total brain volume, which is a marker of good brain health and is linked to a lower risk of dementia and other diseases.

The researchers used Mendelian randomization, a method that relies on genetic data to examine people’s likelihood of habitual napping. They analyzed the napping habits of 378,932 participants from the UK Biobank study and focused on 97 genetic variants previously linked to a tendency to nap.
They found that, overall, people predetermined to nap had a larger total brain volume. On average, the difference in brain volume between nappers and non-nappers was equivalent to 2.5 to 6.5 years of aging, researchers said.

“This is the first study to attempt to untangle the causal relationship between habitual daytime napping and cognitive and structural brain outcomes. By looking at genes set at birth, Mendelian randomisation 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,” lead author and PhD candidate Valentina Paz (University of the Republic (Uruguay) and MRC Unit for Lifelong Health & Ageing at UCL) said.

Dr Garfield added, “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.”

One of the limitations of the study was that all of the participants were of white European ancestry, hence, the findings might not be immediately generalisable to other ethnicities.
Though the researchers are yet to know about the nap duration linked to the benefits, previous suggest that naps of 30 minutes or less provide the best short-term cognitive benefits, and napping earlier in the day is less likely to disrupt nighttime sleep.