A nap is a short period of sleep, usually in the day time. Naps may be taken when one becomes drowsy during the day, otherwise wants to feel awake later in the day, or as a traditional daily practice. It is common for small children to take frequent naps.
Scientists have raised questions as to whether or not napping is beneficial. Gregory Belenky, MD, Research Professor and Director of the Sleep and Performance Research Center at Washington State University, suggests that naps can make up for lost sleep during the night. However, prolonged naps, those exceeding 30 minutes, can lead to sleep inertia, causing the subject to be groggy after the nap. Naps are not recommended for those suffering from insomnia or depression.
A contemporary fad called polyphasic sleep entails avoiding long sleeps, instead taking regularly spaced short naps. Sara Mednick, whose sleep research investigates the effects of napping, included a chapter, Extreme Napping, in her book Take a Nap!. In response to questions from readers about the "uberman" schedule of "polyphasic sleeping", she commented as follows:
This practice rests upon one important hypothesis that our biological rhythms are adaptable. This