Health: A normal afternoon nap of just five minutes can help prevent dementia

Regular afternoon naps – even as little as five minutes a day – can improve your mental agility and help prevent dementia, a study finds.

Researchers from China studied the sleep patterns of 2,214 healthy adults aged 60 or older who lived in several major cities, including Beijing, Shanghai and Xian.

Of the participants, 1,534 reported taking a normal afternoon nap of between five minutes and two hours, while the remaining 680 people did not.

Each of the subjects also took part in a screening test for dementia, with the results showing ‘significant’ differences between the naps and not the groups.

Afternoon sleep was associated with better location awareness, verbal fluency and working memory in the older adults.

As people get older, their sleeping patterns change – and napping is more common.

Previous research has failed to reach consensus as to whether napping could help manage dementia, or if it is in fact a symptom of it.

In the developed world, about 1 in 10 people over the age of 65 suffers from dementia – and this number is increasing as life expectancy increases worldwide.

“In addition to reducing sleepiness, afternoon naps provide several benefits,” the researchers wrote in their paper.

These, they explained, included “memory consolidation, preparation for later learning, improvement in executive functioning, and a boost for emotional stability – but these effects were not seen in all cases.”

However, the team cautioned that the study failed to establish a causal relationship between napping and mental agility – and in addition, noted that the study did not account for the length or timing of naps, which could be important.

However, the team found that those who took regular afternoon naps had higher levels of a fat called triglyceride in their blood – meaning napping is linked to associated risk factors for cardiovascular disease, the study said.

The researchers also put forward some possible explanations for the findings – including the theory that sleep regulates the body’s immune response, and napping could be an evolved response to inflammation.

“People with higher rates of inflammation are also more likely to nap,” the researchers wrote in their paper.

“Scientists continue to work to unravel the relationship between sleep and dementia,” says Sara Imarisio of Alzheimer’s Research UK.

“Unusual sleep patterns are common in people with dementia, but research suggests that sleep changes may be apparent long before symptoms such as memory loss become apparent.”

The authors “could not determine whether a daytime nap directly affected memory and thinking, while the study only showed an association between the two.”

“While other studies have also shown a link between changes in sleep quality, a larger study is needed that looks at a number of sleep-related factors, not just naps,” added Dr. Imarisio.

This, she said, would “paint a clearer picture of the link between dementia and sleep during the day.”

The full findings of the study are published in the journal General Psychiatry.