- 1: to sleep briefly especially during the day : doze
- 2: to be off guard
A nap is a short period of sleep, usually during daytime. Naps may be taken when one becomes drowsy during the day or as a traditional daily practice. It is common for small children and elderly people to take frequent naps. However, naps are not recommended for those suffering from insomnia or depression in order to avoid worsening nocturnal sleep.
Napping has been found to be beneficial. Napping for 20 minutes can help refresh the mind, improve overall alertness, boost mood and increase productivity. Napping may benefit the heart. In a six-year study of Greek adults, researchers found that men who took naps at least three times a week had a 37 percent lower risk of heart-related death. Napping may also relieve headaches.
Scientists have been investigating the benefits of napping for years: the 20-minute nap, as well as sleep durations of 1–2 hours. Performance across a wide range of cognitive processes have been tested. Studies demonstrate that naps are as good as a night of sleep for some types of memory tasks. A NASA study led by David F. Dinges, professor at the University of Pennsylvania School of Medicine, found that naps can improve certain memory functions and that long naps are better than short ones. In that NASA study, volunteers spent several days living on one of 18 different sleep schedules, all in a laboratory setting. To measure the effectiveness of the naps, tests probing memory, alertness, response time, and other cognitive skills were used.
The National Institute of Mental Health funded a team of doctors, led by Alan Hobson, Robert Stickgold, and colleagues at Harvard University for a study which showed that a midday snooze reverses information overload. Reporting in Nature Neuroscience, Sara Mednick, Stickgold and colleagues also demonstrated that, in some cases, a 1-hour nap could even boost performance to an individual's top levels. The NIMH team wrote: "The bottom line is: we should stop feeling guilty about taking that 'power nap' at work."