Search results
Results from the WOW.Com Content Network
Under experimental conditions, humans tend to alternate more frequently between sleep and wakefulness (i.e., exhibit more polyphasic sleep) if they have nothing better to do. [33] Given a 14-hour period of darkness in experimental conditions, humans tended towards bimodal sleep, with two sleep periods concentrated at the beginning and at the ...
Within a few months of postnatal development, there is a marked reduction in percentage of hours spent in REM sleep. By the time the child becomes an adult, he spends about 6–7 hours in NREM sleep and only about an hour in REM sleep. [46] [47] This is true not only of humans, but of many animals dependent on their parents for food. [48]
Polyphasic sleep is the practice of sleeping during multiple periods over the course of 24 hours, in contrast to monophasic sleep, which is one period of sleep within 24 hours. Biphasic (or diphasic , bifurcated , or bimodal ) sleep refers to two periods, while polyphasic usually means more than two. [ 1 ]
Studies have shown that maintaining normal sleep and circadian rhythms is important for many aspects of brain and health. [135] A number of studies have also indicated that a power-nap, a short period of sleep during the day, can reduce stress and may improve productivity without any measurable effect on normal circadian rhythms.
The Oxford English Dictionary's definition of Ultradian specifies that it refers to cycles with a period shorter than a day but longer than an hour. [1] The descriptive term ultradian is used in sleep research in reference to the 90–120 minute cycling of the sleep stages during human sleep. [2]
For premium support please call: 800-290-4726 more ways to reach us
A circadian rhythm is an entrainable, endogenous, biological activity that has a period of roughly twenty-four hours. This internal time-keeping mechanism is centralized in the suprachiasmatic nucleus (SCN) of humans, and allows for the internal physiological mechanisms underlying sleep and alertness to become synchronized to external environmental cues, like the light-dark cycle. [4]
Humans need different amounts of sleep during different stages of life, but individual sleep needs will vary slightly based on genetics, health, behavior and environment.