A nap a day keeps the brain shrinkage away

2 minute read

Making a habit of dozing off before bed could help combat brain ageing by maintaining larger brain volume.

Being the kind of deep sleeper that can slumber through just about anything, including more than one earthquake, this Back Page correspondent has yet to be converted to the wonders of daytime napping.  

However, a new UK study , suggesting a link between regular siestas and better brain health, might be the final straw that breaks this camel’s back.  

Using UK biobank data, the authors studied the genotypes and phenotypes of close to 400,000 participants to see if they could establish a causal relationship between daytime napping and improved brain health. 

Almost 60% of participants reported rarely or never napping during the day, 38% said they napped occasionally and only 4% identified as habitual nappers. The average age for each cohort was between 55 and 59 years old.   

Mendelian randomisation, which is used to examine possible causal associations, identified 92 SNPs relating to daytime napping.  

People with this “genetic liability to daytime napping” – i.e. those who had genes that predisposed them to taking regular naps – had a 15.8 cm3 larger total brain volume than those without the genes, the researchers found. 

They estimated that the larger brain volume observed in those who leaned into their genetic destinies – the predetermined habitual nappers – was equivalent to saving between two to six years in brain ageing. 

However, no difference was observed between habitual nappers and non-nappers in three other measures of brain health and cognitive function – hippocampal volume, reaction time and visual processing. 

According to the authors, their findings indicate that making a habit of dozing off before bedtime could be an important factor in preserving brain health over time.  

“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,” senior author Dr Victoria Garfield told media. 

 “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.” 

Time to log off and ease into a catnap (or two) in the name of science. 

Sending story tips to penny@medicalrepublic.com.au will give you the biggest brain of all. 

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