Regular daytime napping may do more than relieve afternoon fatigue. It could also help preserve brain health and slow cognitive aging, according to a study.
These are the findings of an epidemiological study published in the journal Sleep Health.
The research, led by scientists from University College London and the University of the Republic in Uruguay, found evidence linking habitual daytime napping to larger brain volume, a potential indicator of better brain health and slower neurodegeneration.
THE LINK BETWEEN NAPPING AND BRAIN AGING
The researchers used a technique called Mendelian randomization, which analyzes genetic variants associated with an individual’s likelihood of taking daytime naps.
They examined data from more than 35,000 UK participants aged 40 to 69.
The findings showed that individuals genetically predisposed to daytime napping had a significantly larger estimated total brain volume than those who were less likely to nap.
According to the study, the difference in brain volume was equivalent to the volume typically lost over 2.5 to 6.5 years of normal brain aging, suggesting a potential neurological benefit associated with regular daytime naps.
Using Mendelian randomization, the researchers also investigated whether the relationship could be causal rather than simply an association resulting from other factors related to healthy aging.
WHY THE BRAIN MAY BENEFIT FROM A MIDDAY NAP
Beyond its potential long-term effects on brain health, daytime napping is also associated with immediate benefits, including improved alertness, attention, and executive function.
A short nap may give the brain an opportunity to recover from sustained cognitive demands and the fatigue associated with prolonged wakefulness.
Sleep also supports restorative processes that help the brain clear metabolic waste products accumulated during waking hours.
Daytime napping may additionally help relieve fatigue and support overall well-being, although its specific effects on cortisol levels and cardiovascular strain require further evidence.
HOW LONG SHOULD YOU NAP?
Experts generally recommend keeping daytime naps to around 15 to 30 minutes to reduce the likelihood of sleep inertia.
Sleep inertia refers to the grogginess and temporary decline in alertness that can occur after waking, particularly when a person is awakened from deeper stages of sleep.
Timing also matters. Taking a short nap in the early afternoon, when alertness naturally tends to dip, may help improve alertness without significantly disrupting nighttime sleep.
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