Afternoon naps may prevent cognitive decline and dementia

People who take naps have a lower risk of developing dementia, according to a new study published by The BMJ. The researchers linked afternoon naps of at least five minutes to improved cognitive ability, such as mental agility and speed of thought.

The neurodegenerative changes associated with older age increase the risk of dementia, which affects around 50 million people worldwide. Sleep patterns also change with age, with afternoon naps becoming more frequent.

The study was focused on the sleep patterns of more than 2,200 adults over the age of 60, who were given a standardized screening test for cognitive decline and dementia.

Overall, 1,534 of the participants reported taking a regular afternoon nap of between five minutes and two hours, and the remaining 680 individuals did not take naps. In both groups, the average length of night time sleep was around 6.5 hours.

The analysis revealed that the cognitive performance scores were significantly higher among the nappers compared to those who did not nap. Afternoon naps were associated with higher scores in locational awareness, working memory, and verbal fluency.

Since this is an observational study, the researchers did not establish the underlying cause of the link between afternoon naps and lower levels of cognitive decline. However, the researchers said there are some possible explanations for the observations found.

For example, one theory is that inflammation serves as a mediator between mid-day naps and poor health outcomes. Inflammatory chemicals have an important role in sleep disorders. Sleep regulates the body’s immune response and napping is thought to be an evolved response to inflammation, explained the study authors. 

“In addition to reducing sleepiness, mid-day naps offer a variety of benefits,” wrote the researchers. These include “memory consolidation, preparation for subsequent learning, executive functioning enhancement, and a boost to emotional stability – but these effects were not observed in all cases.”

The study is published in the journal General Psychiatry.

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By Chrissy Sexton, Earth.com Staff Writer