Taking that regular afternoon nap you’re craving may be linked to better mental agility – surely the cue we’ve all be waiting for to grab a blanket and 40 winks.

Nodding off is associated with better awareness of your surroundings, improved verbal fluency and a sharper working memory, a new study published in the online journal General Psychiatry has found.

Our sleep patterns change as we age, meaning we’re more likely to nap during the day. But research to date hasn’t reached any consensus on whether these naps might stave off cognitive decline and dementia in older people – or are a symptom of it.

So researchers explored this in 2,214 ostensibly healthy people aged at least 60 and living in large cities around China, including Beijing, Shanghai, and Xian.

In all, 1,534 took a regular afternoon nap, while 680 didn’t. All participants underwent a series of health checks and cognitive assessments, including the Mini Mental State Exam (MMSE) to check for dementia. The average length of night time sleep was around 6.5 hours in both groups.

People were asked how often they napped during the week. Afternoon naps were defined as periods of at least five consecutive minutes of sleep, but no more than two hours, all of them taken after lunch

The screening tests included 30 checks that measured aspects of cognitive ability, and higher function, including visual-spatial skills, working memory, attention span, problem solving, locational awareness and verbal fluency. 

The MMSE cognitive performance scores were significantly higher among the nappers than they were among those who didn’t nap. And there were significant differences in locational awareness, verbal fluency, and memory, too.

As an observational study, it can’t establish cause. And the exact duration or timing of the naps was not recorded.

One possible explanation for the results, say the researchers, is that inflammation is a mediator between mid-day naps and poor health outcomes – inflammatory chemicals have an important role in sleep disorders, note the researchers.

Sleep regulates the body’s immune response and napping is thought to be an evolved response to inflammation – meaning people with higher levels of inflammation also nap more often, explain the researchers.