Abstract
To the present, intermittent hypoxia training (IHT) has been used extensively for altitude preacclimatization, in sport practice, and for treating a variety of clinical disorders, including coronary artery disease and arterial hypertension, as well as a tool to prepare patients for coronary interventions. Many investigations are primarily focused on the detrimental effects of intermittent hypoxia associated with obstructive sleep apnea (OSA). The following questions arise: Why do OSA and IHT produce such disparate effects on the cardiovascular system? What are the key mechanisms determining the adaptive versus maladaptive nature of different hypoxic paradigms?
An impressive amount of scientific information has been gathered, from the integrative systems level to the molecular and genomic level, but there is no exact evidence of the precise mechanism for switching adaptive or maladaptive responses to hypoxic impact. Nevertheless, basic investigations led to the introduction of various IHT methods in clinical practice and to the development of different medical equipment, named hypoxicators, for their implementation. In particular, clinical data indicate that, in patients with coronary artery disease, IHT reduces daily myocardial ischemia, blood viscosity and platelet aggregation, increases hypoxic tolerance, improves endothelial function, normalizes systemic blood pressure, and so forth.
Recently, a new mode of adaptive training was explored that combines periods of hypoxia and hyperoxia. A novel principle of short-term periodic adaptive training by varying the oxygen level from hypoxia to hyperoxia is substantiated both theoretically and experimentally. We can envisage a bright future for individualized IHT, which may play a significant role in the quickly developing field of personalized preventive medicine against cardiovascular diseases.