## 4 Discussion
These authors, comparing the thermal response and autonomic modulation after PBC and WBC, showed that in both cryotherapy modalities, the mean decrease in Tsk (except the head during PBC) was 8.3 \(\pm\) 0.7 \({}^{\circ}\)C and 8.6 \(\pm\) 1.3 \({}^{\circ}\)C for PBC and WBC, respectively, with a slight drop in the temperature of the head region in response to PBC. The reduction in tympanic temperature was larger after WBC than PBC, i.e., 0.31 \(\pm\) 0.15 \({}^{\circ}\)C vs. 0.07 \(\pm\) 0.12 \({}^{\circ}\)C, respectively. In the cited studies, changes for the Tsk value (calculated on the basis of the analysis from 22 ROIs) were presented, without the analysis for individual areas, which does not allow addressing of the nature of the distribution of changes. They also concluded that both cryostimulation techniques induce an immediate and quite similar autonomic stimulation without the marked effect of head cooling and that the key factor influencing the body response to cryostimulation might be the magnitude of body temperature reduction rather than the head cooling. The results of our research show that the individual factors significantly affecting the temperature changes after cryogenic temperature exposition turned out to be the content of adipose tissue and total body water percentage, as well as blood pressure. On the other hand, the degree of fatigue assessed by the post-match concentration of lactate and muscle fatigue indicators does not affect the thermal response of competitors. An important factor determining the thermal response of football players was the content of adipose tissue, both in absolute and relative values. The drop in skin temperature after PBC for most areas was greater the higher was the content of adipose tissue in the subjects. Skin, adipose tissue, and vasoconstrstricted skeletal muscle form thermal insulators, with heat flux being proportional to the reciprocal of their combined thickness [54]. The relationship between the content of adipose tissue and the temperature of various body areas has been assessed by many authors, showing lower skin temperatures in people with a higher content of adipose tissue [66]. Additionally, it was proven that higher fat percentages in the specific anatomical sites tended to decrease mean skin temperatures of posterior thighs, posterior lower limbs, anterior thighs, and posterior arms; on the contrary, FAT% is positively correlated with body palm and posterior hands temperatures [67]. Extremely low temperature and sudden cold exposure with reduction in body temperature stimulate intense sympathoadrenal activity leading to increase cutaneous venomotor and vasomotor tone (vasoconstriction) and metabolic energy transformation (thermogenesis) to be able to reduce the blood flow in skin tissue and redirect it to the internal organs. Reflex cutaneous vasoconstrtic characterizes the early and sustained response to whole-body cooling and is the primary autonomic mechanism to reduce convective heat transfer and defend core temperature during cold exposure [68]. Adipose tissue shows reduced thermal conductivity and increased insulating capacity and is also an insulating barrier for the conductive heat flow [69]; therefore, these areas may be cooler in thermographic analysis, both after intense physical exercise accompanied by sweating and after cryostimulation. Moreover, there is evidence that the increase in heat production during cold exposure can be three times as large in lean subjects as compared with overweight subjects [70]. As described in the introduction to the study, cold stimulation performed immediately after exercise has become a natural regeneration strategy commonly used in many sports and has proven to be a superior recovery modality when compared with passive recovery [71; 72]. After a football match, physical performance is impaired immediately after the match and recovers gradually to pre-match levels. Several studies failed to observe a normalization of physical performance within the 3 days consecutive to a soccer match.