If you love to nap, join the club. More than 80 percent of us have taken a nap in the last three months, one survey found. That afternoon snooze helps us to feel more relaxed, improves our mood and reduces fatigue.

It also does something more, a study finds. Napping can also help to preserve our brain health.

Researchers from the University College of London (UCL) and Universidad de la República in Montevideo, Uruguay set out to uncover the relationship between daytime napping and overall brain functioning. They focused on reaction time and memory since these are the cognitive abilities most likely to decline as we age. They also looked into the total volume of the brain because volume plays a big role in explaining the differences in our memory and overall thinking ability. And they monitored the hippocampus, the part of our brain which plays a major role in memory and learning.

The team found a causal link between daily naps and larger total brain volume — a marker of good brain health connected to a lower risk of dementia and other diseases.

The team employed a technique called Mendelian randomization. This method works by using genetic markers to evaluate the relationship between exposure and outcome. For example, the way certain of our traits affect certain diseases.

“By looking at genes set at birth, Mendelian randomization avoids confounding factors occurring throughout life that may influence associations between napping and health outcomes. Our study points to a causal link between habitual napping and larger total brain volume,” lead author and PhD candidate, Valentina Paz, of the University of the Republic (Uruguay) and MRC Unit for Lifelong Health & Aging at UCL, said in a press statement.

The researchers analyzed data from nearly 379,000 people between the ages of 40 to 69 who had been part of the large-scale UK Biobank study. UK Biobank is a substantial long-term study that is investigating the respective contributions of genetic predisposition and environmental exposure to the development of disease. It’s worth noting that the research only covered people with white European ancestry, as this group accounted for more than 80 percent of the participants of the Biobank study.

The team examined genetic variations previously discovered to be associated with daytime napping based on the question: “Do you have a nap during the day?” The possible responses were: “never or rarely,” “sometimes,” and “usually.” They also used data from MRIs to study brain volumes, as well as the results of computerized games that involved identifying matches of cards in order to test the participant’s cognitive abilities.

The results did show that napping may hold the key to better brain health. A short, 20-minute snooze is all it takes. Those participants who had genetic variations associated with napping also had larger, on average, total brain volume. Poor sleep may decrease brain volume which impacts overall brain health.

“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, Victoria Garfield, of the MRC Unit for Lifelong Health & Ageing at UCL, said in a statement. The researchers did not find evidence to suggest that napping has an impact on reaction time, visual memory or the specific volume of the hippocampus, however.

Take your nap before 3 pm so it won’t interfere with night time sleep.

But shut-eye eludes many of us. According to the Centers for Disease Control and Prevention (CDC), about 1 in 3 adults in the U.S. report not getting enough rest or sleep. This study suggests that regular napping may act as a safeguard, compensating for inadequate sleep and preserving brain health.

That said, not everyone finds it easy to grab an afternoon nap. Here are tips from the Sleep Foundation that could help:

  • Set an alarm and limit your nap to 20 minutes.
  • Take your nap before 3 pm so it won’t interfere with night time sleep.
  • Choose a good sleep environment that’s cool, quiet and dark.
  • Use accessories such as earplugs or an eye mask to reduce disruptions during your designated nap time.
  • Keep in mind that developing a nap habit that works takes time. You may have to experiment with the timing, duration and location of your nap.

“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,” Garfield added. The study is published in Sleep Health.