We measured 45 biochemical indices of blood serum samples in six volunteers aged 23–35 years before and after 3-min exposure to air cryosauna at a temperature of–70°С. We observed an increase in the activity of glutamate dehydrogenase (by a factor of 3.4), aspartate aminotransferase (by 46%), lipase (52%), lactate dehydrogenase (16%), cholinesterase (18%), leucin aminopeptidase (12%), and prostatic acid phosphatase (45%). Moreover, we observed an increase in the level of free fatty acids (by a factor of 2.8), HDLcholesterol (by 10%), creatinine (21%), glucose and s-hydroxybutirate (11%), high-sensitivity C-reactive protein (12%), potassium (14%), and chlorides (7%). In contrast, atherogenic index values decreased by 14% compared with background level. Most of changes in biochemical blood parameters mentioned above remained almost constant within 20, 60, and 180 min after 3 min of cryosauna; the values did not reach their initial levels. It is concluded that urgent adaptation of human body to low temperatures is associated with increased intensification of reactions in the respiratory chain of mitochondria, an increase in the rate of metabolic reactions due to the elevated production of energy substances resulting from activation of lipolysis and glycolysis.