Lessons from a 20-year investigation of intermittent hypoxia: Principles and practices

Abstract

Widespread use of the intermittent hypoxic training/treatment (IHT) methods in sports, military, and medical practice during recent decades has provoked a discussion: What is 'intermittent hypoxia'? In contrast to studies from the former Soviet Union countries that emphasized mainly the beneficial effects of IHT on an organism, intermittent hypoxia research in Western Europe and North America was primarily focused on the detrimental effects associated with sleep apnea. However, during the past decade, such a gap of division between East and West is progressively shrinking, and mutual understanding on what intermittent hypoxia means becomes clearer. Potential mechanisms underlying both beneficial and adverse effects of IHT have been described. Basic investigations led to the proliferation of various methods of IHT exposure and the development of different medical equipment - hypoxicators - for its implementation in sport practice and military operations and also for clinical application. However, wide array of different protocols and measurements makes the results difficult to harmonize. Meanwhile, the mode of hypoxic influence (depth, duration, and intermittence) appeared to be critical for the determination of healing or harmful result. Therefore, special purposeful investigations are needed to elucidate basic mechanisms of different IHT effects depending on the modality of hypoxic stimuli and elaborate the most effective and safe regimen for the introduction in human practice.