Effect of the Antarctic environment on hormone levels and mood of Chinese expeditioners

Abstract

Background. Serum thyroid hormones, plasma catecholamines and mood were examined in 10 male members of the 16th Chinese Antarctic Expedition who spent the 2000 austral winter at Great Wall Station.Study design. Samples were taken prior to deployment to Antarctica (December, 1999) and upon return to China 54 weeks later (December, 2000). The expeditioners also completed the Profile of Mood States (POMS) each month over an 8-month period (April through November, 2000).Results. There was a significant decrease in levels of serum total thyroxine (p<0.01) and plasma epinephrine (p < 0.05), and a significant increase in serum TSH (p<0.01). With the exception of a significant decline in level of vigor (p=0.008), there were no significant changes in mood throughout the expedition. Low levels of preand post-deployment total triiodothyronine and high levels of TSH were significantly associated with high levels of tension-anxiety, depression, anger, confusion, and total mood disturbance at the beginning and end of winter. High levels of TSH were also significantly associated with high levels of fatigue (p < 0.001), while low levels of total thyroxine were significantly associated with high levels of tension-anxiety (p < 0.001), depression (p < 0.05), and total mood disturbance (p < 0.05). Low levels of dopamine were significantly associated with high levels of tension-anxiety (p < 0.05). An increase in anger during the austral winter was significantly associated with an increase in adrenaline during the expedition (p < 0.05). Conclusion. The increase in TSH, and its association with mood, is consistent with the polar T3 syndrome, while the absence of changes in free triiodothyronine and thyroxine may reflect characteristics of the environment, or racial/ethnic differences in psychophysiological, or sociocultural adaptation to circumpolar environments.