CLAIM: A 2023 UK Biobank study published in Sleep Health, involving genetic data from 378,932 adults, found that habitual daytime nappers had a slightly larger total brain volume than non-nappers—equivalent to an estimated 2.6 to 6.5 years of younger brain ageing. However, daytime napping was not significantly associated with memory or reaction time.

FACT: Multiple studies suggest a link between moderate daytime napping and better cognitive function or slower biological ageing, but experts caution that such findings, largely based on observational or genetic association data, do not prove napping directly improves brain health. They stress that more rigorous research is needed before drawing firm conclusions or recommending lifestyle changes. 

An Instagram account with almost 15 million followers claims that adults who regularly take daytime naps may have bigger brains and that napping could have a protective effect against brain ageing.

The post cites research published in Sleep Health in 2023, which it says finds that adults who regularly indulge in daytime naps may experience a protective effect against brain ageing. According to the post, the brains of people who nap are larger by a volume equivalent to 2.6 to 6.5 years of ageing compared with those of non-nappers.

The post says the study, conducted by researchers at University College London, analyses data from 378,932 participants in the UK Biobank cohort and uses genetic instruments to examine the link between daytime napping and total brain volume.

“While no significant associations were found between napping and cognitive functions like memory or reaction time, the preservation of brain volume is a significant marker in the fight against age-related brain shrinkage,” the caption says.

The post has garnered more than 3.6 lakh likes and over 1,200 comments.

What have the studies found so far?

A study published in 2022 in the journal Sleep Medicine Reviews has found that afternoon naps offer a small but measurable boost to cognitive performance. The study reviewed 54 existing studies covering nearly 2,900 participants across different age groups, from toddlers to older adults, to assess how daytime napping affects memory, alertness, and mental sharpness.

The findings showed naps had a positive effect on memory, speed of thinking, and alertness, though the improvement in planning and decision-making tasks was not significant. The benefits held true regardless of a person’s age, how long the nap lasted, or whether they were used to napping regularly. The study concluded that “naps have a significant small effect size for collective tests of cognition.”

The researchers noted that further large-scale studies are needed to understand how napping affects long-term productivity and to develop practical, personalised recommendations for napping in daily life.

A study published in 2023 in the journal Frontiers in Public Health found that middle-aged and older adults who do not take daytime naps may experience faster biological ageing and more rapid cognitive decline than those who nap moderately. The research analysed data from over 6,600 participants aged 45 and above, drawn from the China Health and Retirement Longitudinal Study, which tracked them over a median follow-up period of 7 years.

The study compared people based on their napping habits, sorting them into non-nappers, short nappers, moderate nappers, and extended nappers. It found that both non-nappers and those who napped for 90 minutes or more had lower cognitive scores and a faster rate of decline than moderate nappers, who napped between 30 and 90 minutes. The study also found that biological ageing may explain part of this link, noting that “the aging status possibly mediates the association between napping and cognition.”

What are experts saying?

Dr Aakash Chheda, neurologist at Zynova Shalby Hospital, Ghatkopar, Mumbai, said the 2023 study does not provide evidence that daytime napping improves brain health or cognitive function.

“A small increase in total brain volume does not mean better brain health or sharper memory,” he said, adding that “brain health depends on several factors, including cognitive function, brain structure, blood flow, and overall neurological health.” He mentioned “the findings of this study should not be interpreted as proof that daytime napping improves cognitive function.”

Dr Chheda also flagged the limits of the study’s genetic approach compared to a clinical trial. “There is no concrete evidence to prove that napping leads to better brain health,” he said, noting that “it is not possible to draw any conclusion based on this study.” He added, “this evidence seems less reliable, and we have to wait and watch regarding this.”

He advised against making any changes to napping habits based on the study. “There is no need to panic or get anxious and change the napping habits,” he said, stressing that “it is too early to act on it” and that people should “consult the expert and clear up all the doubts.”

Dr Chheda further noted, “prolonged daytime naps can make it difficult to fall asleep at night,” and observed that “the study fails to establish whether the duration or timing of naps can impact nighttime sleep in people.”

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