Employees of Laboratory regulatory mechanisms of immunity of the Institute of Physiology of Natural Adaptations of N. Laverov Federal Center for Integrated Arctic Research of the Ural Branch of the Russian Academy of Sciences developed method of professional selection for operation in conditions of possible total cooling by content of irisin in peripheral blood. Method enables detecting individuals capable of withstanding heat deficiency and total cooling. Method is characterized by that irisin content in peripheral blood is examined before and after short-term cold exposure in cold chamber. It is shown that in individuals with short-term cold exposure in a cold chamber for 5 minutes at a temperature of ‒ 25°C, a multidirectional change in irisin content occurs: a decrease in irisin concentration, an increase in irisin concentration and no change in irisin concentration in blood serum. In the absence of changes in the content of irisin or a decrease in its concentrations of less than 25% of the initial level, a conclusion is made about the stability (weak sensitivity) to total cooling, with a decrease in the concentration of irisin by 30% or more, the person being examined is attributed to person’s sensitive to total cooling. Sensitivity to total cooling is associated with a decrease in total white blood cell content by 20% or more of the initial value due to a decrease in the level of lymphocytes, mainly activated T-lymphocytes with receptors to the transferrin (CD71 +), to the IL-2 (CD25+) and to the molecules of the Main Histocompatibility Complex Class II (HLA DR) or due to a decrease in neutrophil content. Irisin has pleiotropic and beneficial properties, so its use is mainly carried out in methods of preventing and treating various diseases. Physical inactivity is increasing in many countries. Sedentary life style is considered to be an independent risk factor for many disorders, including development of type 2 diabetes, obesity, immune dysfunction, asthma, and neurological or coronary heart disease. The multifunctional role and beneficial influence of irisin, the formation of which is induced by physical exercise, has been proved. However, some research data are contradictory. The most of the available data favor irisin as a potential substance for cancer regression through reducing proinflammatory markers linked to obesity. However, some studies showing no or even a negative effect of irisin on cancer. Thus, the continuation of basic scientific research with international cooperation to study the role of irisin is quite relevant.