The length of REM sleep is related to body temperature

According to a new study from the University of California, Los Angeles, the length of REM sleep is related to the body temperature of the animals, and the higher the body temperature, the shorter
the duration of REM sleep.

Groups of warm-blooded animals with lower body temperatures had more rapid eye movement sleep (REM), while groups of animals with higher body temperatures had less REM sleep
.
That's according to new research by UCLA professor Jerome Siegel
.
He says his research shows that REM sleep acts like a "thermostatically controlled brain heater.
"

REM sleep first occurs about 90 minutes after falling asleep
.
After closing your eyelids, your eyes quickly sweep from side to side
.
Mixed-frequency brainwave activity becomes closer to what is seen while
awake.
Your breathing becomes faster and irregular, and your heart rate and blood pressure rise to levels close to when you are awake
.
Most of your dreams occur during REM sleep, although some also occur during
non-REM sleep.
Your arm and leg muscles will be temporarily paralyzed, which prevents you from achieving your dreams
.
As we age, REM sleep provides less and less
sleep.

Siegel said the findings suggest a previously unobserved relationship
between body temperature and rapid eye movement sleep (REM), the brain's highly active sleep phase.
The study, recently published in The Lancet Neurology, was written by Professor Siegel, the author of the Jane and Terry Semel Institute for Neuroscience and Human Behavior at UCLA.
Director
of the Sleep Research Center.

Birds had the highest temperature of any warm-blooded or thermostatic animal at 41 °C (106 °F), but only 0.
7 hours of REM sleep per day was the least
.
This was followed by humans and other placental mammals (37°C/99°F, 2 hours REM sleep), marsupials (35°C/95°F, 4.
4 h REM sleep), and monopores (31°C/88°F, 7.
5 h REM sleep).

Brain temperature drops during non-REM sleep and then rises
during REM sleep.
The pattern, Siegel says, "allows thermostatic mammals to conserve energy during non-REM sleep, without the brain being too cold to respond to threats.
"

REM sleep duration in humans is neither high nor low compared to other thermostatic animals, "which undermines some popular ideas that REM sleep plays a role in learning or mood regulation," he said
.

Reference: "Sleep Function: An Evolutionary Perspective," Dr.
Jerome M Siegel, October 1, 2022, The Lancet Neurology
.
DOI: 10.
1016 / s1474 - 4422 (22) 00210 - 1

Siegel's research was supported by grants from the National Institutes of Health (HLB148574 and DA034748) and the Department of Veterans Affairs Medical Research Service
.
He declared that there were no competing interests
.