NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Melatonin and cortisol assessment of circadian shifts in astronauts before flightMelatonin and cortisol were measured in saliva and urine samples to assess the effectiveness of a 7-day protocol combining bright-light exposure with sleep shifting in eliciting a 12-hr phase-shift delay in eight U.S. Space Shuttle astronauts before launch. Baseline acrophases for 15 control subjects with normal sleep-wake cycles were as follows: cortisol (saliva) at 0700 (0730 in urine); melatonin (saliva) at 0130 (6-hydroxymelatonin sulfate at 0230 in urine). Acrophases of the astronaut group fell within 2.5 hr of these values before the treatment protocols were begun. During the bright-light and sleep-shifting treatments, both absolute melatonin production and melatonin rhythmicity were diminished during the first 3 treatment days; total daily cortisol levels remained constant throughout the treatment. By the fourth to sixth day of the 7-day protocol, seven of the eight crew members showed phase delays in all four measures that fell within 2 hr of the expected 11- to 12-hr shift. Although cortisol and melatonin rhythms each corresponded with the phase shift, the rhythms in these two hormones did not correspond with each other during the transition.
Document ID
20050000213
Acquisition Source
Johnson Space Center
Document Type
Reprint (Version printed in journal)
Authors
Whitson, P. A.
(NASA Johnson Space Center Houston, TX United States)
Putcha, L.
Chen, Y. M.
Baker, E.
Date Acquired
August 22, 2013
Publication Date
April 1, 1995
Publication Information
Publication: Journal of pineal research
Volume: 18
Issue: 3
ISSN: 0742-3098
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Center JSC
NASA Discipline Regulatory Physiology

Available Downloads

There are no available downloads for this record.
No Preview Available