Taking regular naps is good for the brain, study finds

Researchers say they hope their study will reduce any stigma that still exists around daytime napping.

Tom Gillespie

Taking a nap during the day can leave you feeling refreshed, recharged and ready to take on the world. Now new research suggests it could be good for your brain too.

A study which analysed data from people aged 40 to 69 has shown daytime napping could slow the rate at which the brain shrinks as we age.

he average difference in brain volume between habitual nappers and those who were not was equivalent to 2.6 to 6.5 years of ageing, researchers found.

They said they hope their findings into the health benefits of sleeping during the day will reduce any stigma that still exists around daytime napping.

Senior author Dr Victoria Garfield, from the 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.”

Previous research has suggested people who have had a short nap perform better in cognitive tests in the hours afterwards than those who did not take forty winks.

The new study, published in the journal Sleep Health, looked at whether there was a causal relationship between daytime napping and brain health.

Researchers looked at 97 snippets of DNA thought to determine people’s likelihood of habitual napping.

They compared measures of brain health and cognition of people who are more genetically programmed to nap with people who did not have these changes in DNA, using data from 378,932 people from the UK Biobank study.

They found that, overall, people predetermined to nap had a larger total brain volume.

The genetic variants – DNA changes – influencing the likelihood of someone to nap were identified in an earlier study looking at data from 452,633 UK Biobank participants.

But the researchers did not find a difference in how well those programmed to be habitual nappers performed on three other measures of brain health and cognitive function.

Lead author and PhD candidate Valentina Paz, from the University of the Republic (Uruguay) and MRC Unit for Lifelong Health & Ageing at UCL, 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.”

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.”