Inclusion Criteria:  1. Written consent to participate in the study 2. Male or female patients over 18 years 3. Indications for planned replacement of the aortic or mitral valves or operations on the aortic arch.  Exclusion Criteria:  1. Individual intolerance to the intermittent hypoxic-hyperoxic training  2. Acute coronary syndrome after hospitalization and before the surgery  3. The presence of an acute infectious process after hospitalization and before the surgery (fever, leukocytosis with a shift leukocyte formula to the left, increased erythrocyte sedimentation rate (ESR), increased C-reactive protein)  4. Uncompensated hypertension at the time of the procedure (systolic blood pres-sure more than 160 mm Hg, diastolic blood pressure more than 110 mm Hg)  5. Loss of consciousness, severe dizziness  Non-inclusion criteria:  Occlusive atherosclerotic disease of lower limbs, Acute coronary syndrome within 4 weeks before entry Preoperative renal insufficiency (serum creatinine higher than 200 mmol/L), Acute infectious diseases Partial and secondary generalized forms of epilepsy, Uncompensated hypertension (Blood pressure at the time of the procedure: systolic blood pressure more than 160 mm Hg, diastolic blood pressure more than 110 mm Hg) Severe bronchial asthma with the development of respiratory failure of the II-III degree and individual intolerance to oxygen deficiency.  9. Severe hepatic impairment (class C child-Pugh) Intervention type  10. Mental illness (if patients are not capable of understanding the nature, significance and implications of the clinical trial)  11. Myocardial insufficiency as a component of multiple organ failure in decompensation of liver and kidney diseases