Sleep preferences may impact cognitive function and mental acuity, according to a new British study.
- Research also shows that sleeping between 7 and 9 hours per night is optimal for brain function, boosting cognitive functions such as memory, reasoning and information processing speed.
- Another surprising finding: “night owls” generally tend to have higher cognitive scores compared to early risers.
- “It is important to note that this does not mean that morning people have poorer cognitive performance. The results reflect a general trend,” says the lead author.
Diabetes, asthma, depression, allergies… having the habit of going to bed late has been associated with many health problems in the scientific literature. However, the picture would not be totally bleak for night owls, according to a new study led by a team from Imperial College London and published in the journal BMJ Public Health July 10, 2024.
Researchers found that night owls tend to have higher cognitive scores than early risers.
Early risers score higher on cognitive tests
To better understand how sleep quality, habits and preferences impact mental acuity, scientists examined data from more than 26,000 adults. They compared cognitive test scores of people who identified as “morning people” to those who identified as “evening people.”
First observation: sleeping between 7 and 9 hours per night was optimal for brain function, stimulating cognitive functions such as memory, reasoning and information processing speed. On the other hand, sleeping less than 7 hours or more than 9 hours had a clearly harmful effect on the brain’s capacities.
The study also showed that a person’s chronotype—that is, their preference for evening or morning activities—also affected cognitive abilities. Night owls performed better on the tests than early risers, with late risers scoring between 7.5% and 13.5% higher than morning people. Intermediate sleepers—who don’t have a strong sleep preference—also performed better, with cognitive scores between 6.3% and 10.6% higher than early risers.
Sleep and the brain: having healthy sleep habits above all
For the researchers, the differences observed on the cognitive tests of the night owls and the early risers were very significant. Which indicates that it is very unlikely that they are due to chance.
Dr Raha West, lead author of the work, explains in a communicated : “Our study found that adults who are naturally more active in the evening tend to perform better on cognitive tests than those who are ‘morning people’. Rather than simply being personal preferences, these chronotypes may have an impact on our cognitive function.”
She adds : “It’s important to note that this doesn’t mean that morning people have worse cognitive performance. The results reflect a general trend that the majority may lean toward better cognition for evening people. While it’s possible to change your natural sleep patterns by gradually adjusting your bedtime, increasing exposure to evening light, and keeping a consistent sleep schedule, completely switching from a morning person to an evening person is complex.”
For her, what is most important for brain health is having stable and healthy sleep habits such as “sleep just enough, neither too long nor too short”. “It’s crucial to keeping your brain healthy and functioning at its best.”concludes the expert.