Hormonal parameters of saliva and blood of participants of the 21-day Arctic marine expedition

Introduction. It is relevant to study the adaptive changes among the participants of the Arctic marine expedition, which allow for a certain period of time to maintain a stable working capacity necessary to perform various professional tasks. The study aims to identify the dynamics of hormonal parameters in saliva and blood serum samples of the expedition group members who temporarily come to work in the extreme conditions of the Arctic. Materials and methods. Scientists examined 40 participants of the expedition of the Arctic Floating University: 24 women and 16 men aged from 19 to 56 years (the average age is 26 years). They collected saliva in the morning and evening at the beginning, middle and end of the 21-day route. Specialists performed blood sampling in the morning on an empty stomach at the beginning and at the end of the expedition. The levels of cortisol, dehydroepiandrosterone and testosterone were determined by enzyme immunoassay. Results. The concentration of morning salivary cortisol is maximum at the beginning of the route for both men (32.2 nmol/l) and women (31.8 nmol/l), then it decreases significantly by the end of the expedition (8.2 and 8.7 nmol/l, respectively). The reverse dynamics is shown for evening cortisol levels: the maximum values at the end of the route compared with the beginning in men (6.6 versus 1.4 nmol/l) and women (5.5 versus 1.7 nmol/l). The content of morning and evening dehydroepiandrosterone is maximal in women at the beginning of the expedition, then decreases by the end of the route (1.52 and 0.91 nmol/l for morning concentrations, p<0.0001; 0.35 and 0.21 nmol/l for evening concentrations, p=0.013), while it does not significantly change in men. Testosterone levels increase in the middle of the route, more significantly in women (0.26 versus 0.05 nmol/l, p<0.0001). The content of serum hormone concentrations does not significantly change except for the level of dehydroepiandrosterone in men, whose level decreases by the end of the route (47.6 versus 65.4 nmol/l, p=0.038). Limitations. Most of the participants did not have the opportunity to measure the background values of the indicators before the route, which, of course, would have been of great value. Conclusion. The hormone content in saliva, rather than in serum, is an informative indicator reflecting hormonal changes in the body of participants in the Arctic expedition associated with the presence of acute stress caused by natural factors and specific working conditions. An increase in evening cortisol and testosterone levels indicates a violation of their circadian dynamics and the possible development of desynchronosis in the expedition members by the end of the route. An increase in dehydroepiandrosterone at the beginning of the expedition and testosterone from the middle of the route may indicate their adaptive and neuroprotective role under the influence of a complex of stressful conditions of the expedition and increased mental stress. Ethics. The study was conducted in compliance with Ethical standards (Minutes No. 2 of the meeting of the Ethics Committee of the N. Laverov Federal Center for Integrated Arctic Research of the Ural Branch of the Russian Academy of Sciences dated 06.06.2024).