@article{ref1,
title="Melatonin and cortisol assessment of circadian shifts in astronauts before flight",
journal="Journal of Pineal Research",
year="1995",
author="Whitson, P. A. and Putcha, L. and Chen, Y. M. and Baker, Elina",
volume="18",
number="3",
pages="141-147",
abstract="Melatonin 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.<p /><p>Language: en</p>",
language="en",
issn="0742-3098",
doi="",
url="http://dx.doi.org/"
}