@article{ref1,
title="Effects of high altitude and cold exposure on resting thyroid hormone concentrations",
journal="Aviation, space, and environmental medicine",
year="1995",
author="Hackney, A. C. and Feith, S. and Pozos, R. and Seale, J.",
volume="66",
number="4",
pages="325-329",
abstract="This study examined the effect of high altitude and cold exposure on thyroid hormone status during a mountaineering expedition. There were 15 males participating in an expedition to climb Mt. McKinley, AK. Resting blood samples were collected and analyzed for thyroid-stimulating hormone (TSH), total (T)-free (f) thyroxine (T4), triiodothyronine (T3), reverse T3 (rT3), and cortisol. Measurements were made on three occasions: baseline in the continental U.S. one week pre-expedition (PRE-I), baseline in Alaska immediately pre-expedition (PRE-II), and immediately upon descent post-expedition (POST). Statistical analysis indicated that no significant trial PRE-I vs. PRE-II (p > 0.05) differences occurred. Significant (p < 0.05) reduction, however, occurred from PRE-II to POST expedition in TSH, TT3, and fT3. Also rT3 and cortisol increased significantly PRE-II to POST while TT4 and fT4 were unchanged. The increase (delta = POST minus PRE-II) in cortisol was negatively correlated with the decrease (delta) in TSH (r = -0.52, p = 0.05) and TT3 (r = -0.49, p < 0.06). Moreover, the reduction in TT3 was inversely correlated with the rT3 increase (delta comparison, r = -0.66, p < 0.01). The findings demonstrate that the resting concentrations of thyroid hormones are disrupted by a mountaineering expedition, specifically an environmental stress-related &quot;low T3 condition&quot; seems to develop. These changes would seem to be related to an impaired peripheral conversion of T4 to T3, possibly brought about by elevations in the circulating cortisol levels.<p /><p>Language: en</p>",
language="en",
issn="0095-6562",
doi="",
url="http://dx.doi.org/"
}