## 4 Discussion
The SG group was characterized by higher R\({}^{0}\) values in the cutometric measurement, indicating lower skin firmness than observed in subjects with normal BMI values. It is worth noting that the average age of the two groups was similar to each other, and therefore the influence of age on this skin parameter can be excluded. The influence of obesity on the rate of aging of the body including the skin has been increasingly noted in the literature [47; 48; 49]. [PERSON] et al. [47] pointed to strong correlations between obesity and facial skin aging. In a study on an animal model [50], it was observed that the collagen content of the skin was similar in a group of obese and lean mice, but the surface area of the obese skin was 60% larger which translates into a weaker mechanical strength of this tissue. The skin of the obese subjects in the present study responded differently to the cryogenic stimulus than the skin of subjects with normal BMI values. Before the 10 th treatment, the SG's skin on the forearm had lower corneometric values than baseline and higher traumatic values, followed by an increase in these values. The forearm skin of normal-weight subjects reacted inversely. There was an initial increase in these values and a decrease between the 10 th and 20 th treatments. The pH value initially increased in the SG, with a subsequent decrease in values. Again, the CG's skin reacted inversely. [PERSON] et al. [51] noted no differences in epidermal thickness among obese (BMI 35-50) and normal-weight (BMI 18-27) subjects. The present study did not examine epidermal thickness. There is an important element that is worth considering in future studies using high-frequency ultrasound imaging. Obesity causes structural and functional changes in microvessels, including endothelial dysfunction. However, studies of obese individuals have noted significant alterations in the expression of genes encoding proteins that alter skin oxygenation and may contribute to poorer wound and ulcer healing [51]. Control of vascular tone and secretion of paracrine factors is impaired, affecting organ function and contributing to an altered release of adipokines and inflammatory cytokines [52]. As mentioned earlier, cryotherapy results in enhanced microvascular reflex. Systemic microvascular dysfunction in obese individuals may therefore also affect the skin and the effectiveness of treatments. Accordingly, it can be concluded that the skin of obese people, with a baseline higher degree of vascular dysfunction, responds more strongly to the cryogenic stimulus. Individuals exposed to a series of repeated, intermittent periods of cold exposure should exhibit a number of physiological adaptations that alter the strength and quality of the body's response to the initial episodes of cold exposure [19]. The present study, however, indicates that the vast majority of skin parameters studied do not show adaptations to the cryogenic stimulus, and each treatment, regardless of whether it is the first or last in a series, produces an identical effect. Adaptation differences were observed for TEWL on facial skin in the group of subjects with higher BMI (the last treatment induced a stronger effect than the first treatment). Similarly, different responses to the first and last treatments in the series were observed in skin hydration and for the R\({}^{0}\) parameter in SG. In each case, these changes were on the skin on the forearms, which, as described earlier, responds more strongly than the skin on the face. The present study confirms the positive effects of 20 WBC treatments on the skin, particularly in obese individuals. Other works have also indicated the positive effects of WBC treatments in obese individuals on weight and fat loss [6; 53; 54], improvement of lipid profile [55], and anti-inflammatory effects of this form of physical treatment [6; 20; 56]. Thus, cryogenic treatments should be considered as a safe form of health support for people struggling with overweight and obesity.