Sex-specific features of neuroendocrine and immune responses in women and men during the Ukrainian Antarctic Expedition
- adaptation,
- Cooper test,
- cortisol,
- neuroendocrine regulation,
- NK cells
- testosterone ...More
Copyright (c) 2026 Ukrainian Antarctic Journal

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Abstract
We investigated sex-specific features of neuroendocrine, cardiovascular, and immune responses in participants of the Ukrainian Antarctic expeditions during prolonged isolation, as well as in response to acute physical exercise, with a comparative evaluation in women and men. The study included 22 men and 9 women who spent one year at the Ukrainian Antarctic Akademik Vernadsky station, as well as control groups residing in Kyiv. Blood samples were collected before the expedition, quarterly during the stay at the station, and after returning to Kyiv. Serum cortisol, testosterone, and growth hormone levels were measured using enzyme-linked immunosorbent assay (ELISA), while lymphocyte subpopulations were analysed by flow cytometry. A modified Cooper test was used as a model of acute physical exercise to assess physiological responses among expedition candidates. The results showed that cortisol levels increased already in the first quarter of the expedition in participants of both sexes, suggesting activation of the hypothalamic–pituitary–adrenal axis during adaptation to Antarctic conditions. In men, peak cortisol levels were observed at the early stages of the expedition, whereas in women, a more gradual increase was noted, with peak values occurring later in the mission. Testosterone levels increased in both sexes during the expedition; however, after returning to normal conditions, they tended to normalise primarily in men. In women, the increase in heart rate was less pronounced, and recovery of hemodynamic parameters was faster after exertion. The immune response to physical stress also showed sex-related differences: in men, a statistically significant increase in the absolute number of NK cells was observed after exercise, whereas in women these changes were less pronounced; no significant changes in the absolute number of T helper cells were detected in either group. The obtained results indicate that neuroendocrine adaptation to prolonged Antarctic isolation exhibits sex-specific characteristics, but is not associated with evidence of poorer clinical tolerance in women.
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