Despite leaps and bounds in the past century, neuroscience remains both fascinated and challenged by the mystery of sleep. Sleep science intersects with neuroscience and countless other scientific fields due to the whole-body nature of rest. Similarly, aging is a process which affects the whole body, especially the brain. The brain atrophies and shrinks as one ages, and greater shrinkage is associated with greater cognitive declines. Interestingly, a British study in Sleep Health has discovered that short daytime naps may be protective against shrinkage. Specifically, there was a “modest causal link between habitual napping and larger total brain volume,” which may be protective.
The study used data from the UK Biobank, a pool of data on 500,000 participants who entered the dataset at age 40 to 69. Researchers from University College London and the University of the Republic in Uruguay culled data from 35,080 to examine the effects of naps. They examined those who, like about 1% of the population, have a genetic variant that predisposes them to daytime napping. “It is like a natural randomized control trial,” Dr Victoria Garfield, a co-author of the study from UCL, told The Guardian. Participants had self-reported their napping habits, and brain volume was measured.
Controlling for other factors affecting brain size, the team discovered that the gene variant which triggers a napping nature was associated causally with a larger brain volume. This brain volume lead is the equivalent of about 2.6 to 6.5 years less aging. While there are many confounding variables affecting brain health (and cognitive differences in this study did not necessarily track brain size), maintaining brain volume is generally a good goal. Though the study only focused on a white, British subpopulation, Dr. Garfield notes the results that could benefit a large population of people: “It could be having a short daytime nap … could help preserve brain volume and that’s a positive thing, potentially, [for] dementia prevention.” The researchers recommend 30 minute naps, if you're looking to try out this possibly protective (and arguably enjoyable) strategy for brain health.
A British study of those pre-disposed to daytime naps demonstrates this habit is associated with larger brain volume and less shrinkage.
h/t: [The Guardian]