SLEEP-WAKE ACTIGRAPHY AND LIGHT EXPOSURE DURING SPACEFLIGHT – LONG
AND SHORT (SLEEP), TWO INVESTIGATIONS
Research Area: Human Behavior and Performance
Expeditions: 14- 26
Principal Investigator(s): ● Charles A. Czeisler, MD, PhD, Harvard Medical School,
Boston, Massachusets
● Laura K. Barger, PhD, Brigham and Women's Hospital, Harvard
Medical School, Boston, Massachusets
RESEARCH OBJECTIVES
Sleep-Wake Actigraphy and Light Exposure During Spaceflight examines the effects of space
flight and ambient light exposure on the sleep-wake cycles of crew members during shuttle
missions and long-duration stays aboard the International Space Station (ISS). Advancing state-
of-the-art technology for monitoring, diagnosing, and assessing treatment of sleep patterns is
vital to treating insomnia on Earth and in space.
EARTH BENEFITS
A better understanding of insomnia is relevant to the millions of people on Earth who suffer
nightly from insomnia. The advancement of state-of-the-art technology for monitoring,
diagnosing, and assessing treatment effectiveness
is vital to the continued treatment of insomnia on
Earth. This work has the potential to greatly benefit
the health, productivity, and safety of groups with
a high prevalence of insomnia, such as shift
workers and the elderly.
SPACE BENEFITS
The information gained from this study leads to a
better understanding of the effects of spaceflight
on sleep-wake cycles. The countermeasures that
may be developed based on the findings of this
study could improve sleep during missions, which,
in turn, help to maintain alertness and lessen
fatigue of the crew during long-duration
spaceflights.RESULTS
Even when speeding at over seventeen thousand
miles an hour, astronauts find it tough to catch
enough Z’s. A comprehensive analysis of results,
collected over a ten-year span, shows that Shuttle and International Space Station crew
members have difficulty falling asleep and typically do not get the full amount of sleep
recommended for them each night. Sleep researchers studied diary entries and rest/activity
S104E5114 – Astronaut Janet Kavandi on STS-
104 is wearing an Actiwatch on her right wrist for
recording activities.