## 3 Results

Table 3: Descriptive statistics: hormones. Variables are shown as mean values \(\pm\) standard deviation (SD). time \(\times\) group interaction (\(p\) > 0.05). However, there was a trend (0.10 \(>\)\(p\) > 0.05) indicating a very slight decrease in the results of this scale (by 0.15 points) in the whole sample of respondents. As for anger-hostility, a significant decrease in the intensity of this emotional state (by 0.42 points) was observed in all subjects. No significant time \(\times\) group interaction was reported (\(p\) > 0.05). As for fatigue, a statistically significant decrease in the perceived fatigue was revealed for both whole sample analysis (by 0.57 points) and time \(\times\) group interaction. In the case of the observed interaction, it was found that in the winter swimming group, the reduction in the perceived fatigue (by 0.86 points; post hoc Tukey: \(p\) < 0.001; Wilcoxon: \(p\) = 0.001; \(\tau_{\rm{rb}}\) = 0.950) was significantly larger than that in the control group (by 0.28 points; \(p\) > 0.05). As for confusion, in the third measurement, a decrease of 0.29 points in the results was reported by all participants. No significant time \(\times\) group interaction was noted (\(p\) > 0.05). As for vigor, no significant changes were reported concerning vigor intensity for all studied subjects and with the consideration of time \(\times\) group interactions (\(p\) > 0.05) (Figure 2). When analyzing the results of the Wilcoxon test, more differences were noted than in the GLM analysis. In the winter swimming group, significant decreases were observed in the outcomes of depression-dejection (\(p\) = 0.025; \(\tau_{\rm{rb}}\) = 0.714), anger-hostility (\(p\) = 0.004; \(\tau_{\rm{rb}}\) = 0.850), and confusion (\(p\) = 0.033; \(\tau_{\rm{rb}}\) = 0.657). In turn, no changes were reported in the control group (\(p\) > 0.05). Analyses involving non-parametric tests do not permit examining the interaction of time \(\times\) group. It is, therefore, difficult to assess the effect of winter swimming on these emotional states. Additionally, in the group of winter swimmers, an analysis was performed for three measurements (24 h before the single cold-water immersion, immediately after the single cold-water immersion, and 24 h after the single cold-water immersion) with the use of the POMS questionnaire. With reference to POMS results (Figure 3, Table 2), several significant changes were reported. As for tension-anxiety, statistically significant changes were noted; immediately after leaving the water, the subjects' tension-anxiety level was reduced (by 0.47 points; post hoc Tukey: \(p\) = 0.002; post hoc Durbin-Conover: \(p\) < 0.001). This result was maintained up to the moment of the measurement carried out 24 h after the single cold-water immersion (phase 1 vs. phase 3: post hoc Tukey: \(p\) < 0.001; post hoc Durbin-Conover: \(p\) < 0.001). For the results of the depression-dejection scale, a statistically significant change was also reported. In this case, a reduction in measurement 2 was observed (by 0.20 points; nonsignificant \(p\) > 0.05), which was further reduced in measurement 3 (significant post hoc Tukey: \(p\) = 0.042; post hoc Durbin-Conover: \(p\) = 0.003). Moreover, a corresponding reduction in anger-hostility was noted immediately after emerging from the water, the anger-hostility status was reduced by 0.59 points (post hoc Tukey: \(p\) = 0.018; post hoc Durbin-Conover: \(p\) = 0.007) and remained at this low level until the third measurement (phase 1 vs. phase 3: post hoc Tukey: \(p\) = 0.009; post hoc Durbin-Conover: \(p\) = 0.015). The state of vigor also changed immediately after emerging from the water, and it was improved by 0.27 points (post hoc Tukey: \(p\) = 0.095; post hoc Durbin-Conover: \(p\) = 0.031); then, after 24 h, a return of this state to the level of the first measurement was recorded (phase 2 vs. phase 3: post hoc Tukey: \(p\) = 0.066; post hoc Durbin-Conover: \(p\) = 0.039).