The power of afternoon naps3 min read . Updated: 08 Apr 2013, 09:28 PM IST
Studies show short naps help rejuvenate the body, mind and spirit
I have been taking 20-minute afternoon naps every day for the past 25 years," says Suresh Pingale, 73, agriculturist and former president of the Rose Society of India. “I knew I was on the right track when I learnt that Sir Winston Churchill believed in afternoon naps too. I find that naps refresh me and allow me to keep up with my work and other commitments till 10.30pm at night. It’s like getting two days in one."
Scientists have been studying afternoon naps for a while and in March 2012, a review of scientific articles on afternoon naps, Prioritizing Sleep For Healthy Work Schedules, was published in the Journal of Physiological Anthropology. The review by Masaya Takahashi, of the National Institute of Occupational Safety and Health, Kawasaki, Japan, sheds light on how power naps help rejuvenate the body, mind and spirit.
Takahashi’s review found that studies on brief power naps of 15-20 minutes, taken in the middle of the workday, show an improvement in brain function by increasing our ability to learn and remember. A study in Academic Medicine in October, published after Takahashi’s review, had similar results. The sleep study was conducted by Avram Gold and colleagues at the division of pulmonary, critical care and sleep medicine, Stony Brook University, Northport, New York, US, and they looked at the effects of a 20-minute afternoon nap on 29 first-year medical residents, a particularly sleep-deprived lot of professionals. The study found that the 18 medical residents who took a nap were far more alert and less error-prone for the rest of their workday compared to the 11 who stayed awake during that period.
And the length of the nap seems to be important.
In another research study that Takahashi undertook, he says in an email interview, “we found that a 15-minute nap after lunch produced higher alertness and task performance than being awake or after a 45-minute nap."
It is not only the brain that benefits from a power nap. Takahashi quotes the results of a study in his review where scientists found that men who napped for 30 minutes three times a week at least showed a 50% decrease in their risk of dying of heart attacks. Why this could be the case is unclear but Takahashi writes that it could be because levels of IL-6, an immune molecule associated with inflammation, go down after a nap. IL-6 is a pyrogenic cytokine, an immune molecule that produces fever, and it’s no surprise then that when you are running a sleep debt because of jet lag, for example, the unique exhaustion that follows has a feverish quality to it.
For night-shift workers, a siesta is particularly beneficial. It increases alertness and reduces work-related musculoskeletal pain like neck, arm and leg pain. Levels of IL-6 go up with one night’s sleep deprivation, and while a 2-hour nap reverses this increase in IL-6 by quite a bit, its levels continue to drop after the nap.
In India, overworked CEOs could benefit greatly from scheduled naps, says Ashim Desai, senior ENT consultant, Nova Specialty Surgery (NSS), Mumbai. Dr Desai is running a study on sleep-related disorders across five NSS centres in the country. He estimates that about 10% of the Indian adult population has some sleep disorder and those with sleep apnoea can’t go through a workday without an afternoon nap that lasts for at least an hour or so.
He adds, “If you need a 1- to 2-hour afternoon nap every day, that indicates a sleep debt from the night before, and there is a good chance you have sleep apnoea. For other people, a 15-20 minute nap is enough for improving mental alertness. If you sleep longer than that then your biorhythm can go for a toss, disrupting melatonin levels and making it harder for you to sleep at night."
If we had to pick one part of our body that benefits the most from an afternoon nap then, Takahashi says in the email interview, it would be the brain. A number of sleep studies on brain function show that afternoon naps benefit our alertness, reduce errors, and enhance memory and retention capabilities.
Churchill was a believer in power naps and once famously said: “You must sleep sometime between lunch and dinner, and no half measures. Take off your clothes and get into bed." While we may not be able to take off our clothes in the middle of the day and take a nap the way Churchill suggested, it may be worthwhile to find ways to steal 15-20 minutes in the afternoon for a relaxing siesta.
Sujata Kelkar Shetty, PhD, writes on public health issues and is a research scientist trained at the National Institutes of Health in Bethesda, US.