Polyphasic sleep is the practice of sleeping multiple times in a 24-hour period—usually more than two, in contrast to biphasic sleep (twice per day) or monophasic sleep (once per day). The term was first used in the early 20th-century by psychologist J. S. Szymanski, who observed daily fluctuations in activity patterns (Stampi 1992). It does not imply any particular sleep schedule. The circadian rhythm disorder known as irregular sleep-wake syndrome is an example of polyphasic sleep in humans. Multiphasic sleep of normal total duration An example of polyphasic sleep is found in patients with irregular sleep-wake syndrome, a circadian rhythm sleep disorder which usually is caused by head injury or dementia. In their 2006 paper "The Nature of Spontaneous Sleep Across Adulthood," Campbell and Murphy studied sleep timing and quality in young, middle-aged, and older adults. In extreme situations Dr. U.S. military The U.S. military has studied fatigue countermeasures.
Related: Sleep Research
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