Sleep duration, efficiency and structure change in space

Date:
August 26, 2020
Source:
American Academy of Sleep Medicine
Summary:
It's hard to get a good night's sleep in space. An evaluation
of astronauts serving on the Mir space station found that they
experienced shorter sleep durations, more wakefulness, and changes
in the structure of their sleep cycles while in microgravity.



FULL STORY ==========================================================================
It's hard to get a good night's sleep in space. An evaluation of
astronauts serving on the Mir space station found that they experienced
shorter sleep durations, more wakefulness, and changes in the structure
of their sleep cycles while in microgravity.


========================================================================== Researchers at Harvard College, Harvard Medical School, and NASA Ames
Research Center studied the sleep patterns of four cosmonauts and one
astronaut before, during and after spaceflight to conduct missions on
the space station.

Preliminary results show that they slept an average of only 5.7 hours in
space, compared with 6.7 hours on Earth. They also spent significantly
more time awake in bed, leading to a 17.7% reduction in sleep efficiency.

In space their time in non-REM and REM sleep decreased by 14.1% and 25.8% respectively. On average it also took about 90 minutes after falling
asleep for astronauts to reach their first episode of REM sleep in space, nearly 1.5 times longer than on Earth. In contrast, most sleep measures
were stable across the inflight phase, with the exception of a decrease
in the amount of time spent in bed and an increase in the length of time
it took to fall asleep after going to bed.

"There were marked shifts in sleep architecture compared to baseline,
and some of these evolved over the course of the mission," said lead
author Oliver Piltch, an undergraduate researcher at Harvard College. "Our findings were consistent with previous studies that focus on the issue
of sleep continuity.

We found significant decreases in sleep efficiency during spaceflight
despite similar times in bed." Piltch said scientists need to understand
how sleep is affected by spaceflight to better equip astronauts for
success on long-duration flights, like a trip to Mars or the Moon. He
noted that the research also has implications for sleep on Earth.

"The significant sleep changes induced by the extreme environmental
conditions of spaceflight can magnify and help reveal similar, though potentially less noticeable, changes that are induced by the more
moderate conditions of Earth," he said. "Our results support other
studies indicating that sleep architecture can adapt to different
environments. Also, the sleep deficits that our subjects were facing
while working around the clock in a high-pressure environment provide
further evidence for the danger of stress and shift-work schedules for
humans anywhere." Statistical analyses of the research were guided by
Erin Flynn-Evans, PhD, director of the NASA Fatigue Countermeasures
Laboratory. The experiment was designed and led by Robert Stickgold,
PhD, director of the Sleep and Cognition Lab at Beth Israel Deaconess
Medical Center and professor of psychiatry at Harvard Medical School,
alongside Dr. J. Allan Hobson, professor emeritus of psychiatry.


========================================================================== Story Source: Materials provided by
American_Academy_of_Sleep_Medicine. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. R Stickgold, E Flynn-Evans, O Piltch. 0278 Changes in Sleep
Architecture
During Long-Duration Spaceflight. Sleep, 2020; 43 (Supplement_1):
A105 DOI: 10.1093/sleep/zsaa056.276 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200826110331.htm

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