Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Pitt research shows NASA sleep-wake scheduling guide may need to be changed

07.12.2004


New research from the University of Pittsburgh shows the human body has difficulty adjusting to dramatic time changes such as those experienced by working shifts or traveling across time zones.



The NASA-funded study, detailed in this month’s Aviation, Space and Environmental Medicine, was designed to examine the protocols the space agency uses to assign sleep-wake schedules that ensure astronauts are always able to handle their demanding tasks at peak performance. The findings suggest changes should be made in the way NASA schedules sleep periods on missions, but also have meaning for anyone who has had to deal with a significant time change and still function.

"Many of us find that we have to change our sleep schedule, perhaps to accommodate work or school start times, or a change in our commute time," said Timothy H. Monk, Ph.D., professor of psychiatry at the University of Pittsburgh School of Medicine and lead author. "We often wonder if we should make the change all at once, or more gradually over several days or weeks. This research has the eventual aim of helping us make that decision in the best way possible."


According to Dr. Monk, early in the history of manned space flight, NASA realized that it had to have a method for assigning sleep periods to correspond to astronauts’ biological clock rhythms if they were to get enough rest to do their assignments. "If they scheduled sleep for the wrong time, an astronaut could end up having disrupted and unrefreshing sleep, leaving them feeling tired and irritable, and perhaps more apt to make mistakes."

Getting the right amount of sleep at the right time is more complicated in space than it is on Earth. On Earth, people are used to having time cues tell their bodies when it is time to sleep or to wake up. The strongest of these is the 24-hour day-night cycle, which comes from the fact that we live and have evolved on a planet with a 24-hour rotation. Like most animals we have a biological clock in our head, which is able to keep time, getting us ready for sleep at night and wakefulness during the day using rhythms with a period of about 24 hours – referred to as circadian rhythms. In orbit, the sunrise-sunset cycle lasts for a mere 90 minutes, and after the absence of the natural 24-hour cycle for three months or more, the biological clock starts to weaken. When the biological clock gets thrown off balance, sleep and alertness suffer.

Complicating the issue is the need for astronauts to be awake and alert to undertake sensitive mission goals – say docking with another vessel – at specific times that may fall during a time at which they are normally asleep.

To reconcile an astronaut’s need for sleep with their busy schedules, NASA originally developed guidelines referred to as "Appendix K." These guidelines specified how much time had to be set aside for sleep and for the transitions to and from it. It also specified by how much an astronaut’s bedtime could change from one day to the next. It favored "trickling in" changes rather gradually, using phase delays to later bedtimes (by up to 2 hours) wherever possible.

The concept is similar to the terrestrial example of the common traveler’s advice to move one’s bedtime ahead or back a little at a time in the week before an overseas trip to help minimize jet lag. "The thought was that mission schedulers could trickle in a series of two-hour phase delays without incurring any negative consequences as far as sleep quality and alertness," said Dr. Monk. "However, based on the findings from this experiment, that assumption might be quite wrong."

The researchers observed participants, who volunteered to spend 16 days on a "mission" at the University of Pittsburgh’s time isolation facilities, and tested them for alertness, mood and core body temperature – the best standard for assessing circadian rhythms. At the same time they recorded their sleep to assess its duration and quality. The experiment involved a series of nine repeated two-hour delays in bedtime.

During the study Dr. Monk and his colleagues found that the circadian pacemaker did adjust itself – but only by about one hour per night rather than the two hours required by NASA’s protocol. Because of that, subjects eventually experienced a massive flattening in the amplitude of their circadian temperature rhythm indicating that the biological clock was not doing its job properly. This led to significant disruptions in sleep and lowered alertness while awake.

More research needs to be done before scientists can advise NASA on how to change its guidelines. "There is always some cost to performing tasks when we expect to be asleep, but by the end of the series of experiments, of which this is the first part, we shall be able to advise NASA which approach – gradual delays, gradual advances, all at once – will lead to the least disruption of an astronaut’s sleep and alertness," said Dr. Monk.

Co-authors include Daniel J. Buysse, M.D., Bart D. Billy, M.S. and Jean M. DeGrazia, M.Ed. The National Institute on Aging provided additional research support.

Craig Dunhoff | EurekAlert!
Further information:
http://www.upmc.edu

More articles from Health and Medicine:

nachricht NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures
17.11.2017 | National Institute of Standards and Technology (NIST)

nachricht High speed video recording precisely measures blood cell velocity
15.11.2017 | ITMO University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Carefully crafted light pulses control neuron activity

20.11.2017 | Life Sciences

SYSTEMS INTEGRATION 2018 in Switzerland focuses on building blocks for industrial digitalization

20.11.2017 | Trade Fair News

Heavy nitrogen molecules reveal planetary-scale tug-of-war

20.11.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>