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This pattern was common in preindustrial societies, and it was most common to sleep early ("first sleep"), wake around midnight, and return to bed later ("second sleep"). [10] Along with a nap in the day, it has been argued that this is the natural pattern of human sleep in long winter nights.
Sample hypnogram showing one sleep cycle (the first of the night) from NREM through REM. The sleep cycle is an oscillation between the slow-wave and REM (paradoxical) phases of sleep. It is sometimes called the ultradian sleep cycle, sleep–dream cycle, or REM-NREM cycle, to distinguish it from the circadian alternation between sleep and ...
Research suggests that sleep patterns vary significantly across cultures. [146] [147] [148] The most striking differences are observed between societies that have plentiful sources of artificial light and ones that do not. The primary difference appears to be that pre-light cultures have more broken-up sleep patterns.
People who read from an iPad for 30 minutes before going to sleep felt less sleepy and had different electrical activity in the brain during sleep. Reading from a tablet before bed may affect ...
Needing more sleep during the winter may also be due to what’s known as “social jet lag,” experts said, meaning that the fun, late nights you had all summer may be why you’re having ...
Among mammals, infants sleep the longest. [44] Human babies have 8 hours of REM sleep and 8 hours of NREM sleep on an average. The percentage of time spent on each mode of sleep varies greatly in the first few weeks of development and some studies have correlated this to the degree of precociality of the child. [45]
Rapid eye movement sleep (REM sleep or REMS) is a unique phase of sleep in mammals (including humans) and birds, characterized by random rapid movement of the eyes, accompanied by low muscle tone throughout the body, and the propensity of the sleeper to dream vividly. The core body and brain temperatures increase during REM sleep and skin ...
Free-running sleep is a rare sleep pattern whereby the sleep schedule of a person shifts later every day. [1] It occurs as the sleep disorder non-24-hour sleep–wake disorder or artificially as part of experiments used in the study of circadian rhythms and other rhythms in biology .