Hormonal and Psychological Responses to a Single Cold-Water Immersion in Regularly Winter-Swimming Males

The psychological response to cold is complex. The present study aimed to determine if regular winter swimmers differed from those who did not practise winter swimming in terms of (1) daily perceived emotional states, (2) subjectively perceived satisfaction with life, and (3) hormone concentrations. An additional objective was to investigate how a single immersion in cold water in regular winter swimmers affected their subjectively assessed emotional states and levels of stress hormones. The study involved 30 males aged 30–50 years. The experimental group consisted of 15 males who regularly practised winter swimming. The control group (n = 15) had no contact with cold water. Three measurements were taken in the study: 24 h before cold-water immersion, immediately after coming out of the 4 °C water, and 24 h after cold-water immersion. Winter swimmers had significantly higher adrenaline levels than controls. Moreover, 24 h after cold-water immersion, the winter swimming group was characterized by a significant reduction in noradrenaline and adrenaline concentrations and a slight increase in cortisol concentration compared with the control group. Of interest, a slight increase in serotonin levels in the control group was observed, unlike in the winter swimming group. Dopamine levels remained unchanged.