Intermittent hypoxia: a low-risk research tool with therapeutic value in humans

Abstract

Intermittent hypoxia has generally been perceived as a high-risk stimulus, particularly in the field of sleep medicine, because it is thought to initiate detrimental cardiovascular, respiratory, cognitive, and metabolic outcomes. In contrast, the link between intermittent hypoxia and beneficial outcomes has received less attention, perhaps because it is not universally understood that outcome measures following exposure to intermittent hypoxia may be linked to the administered dose. The present review is designed to emphasize the less recognized beneficial outcomes associated with intermittent hypoxia. The review will consider the role intermittent hypoxia has in cardiovascular and autonomic adaptations, respiratory motor plasticity, and cognitive function. Each section will highlight the literature that contributed to the belief that intermittent hypoxia leads primarily to detrimental outcomes. The second segment of each section will consider the possible risks associated with experimentally rather than naturally induced intermittent hypoxia. Finally, the body of literature indicating that intermittent hypoxia initiates primarily beneficial outcomes will be considered. The overarching theme of the review is that the use of intermittent hypoxia in research investigations, coupled with reasonable safeguards, should be encouraged because of the potential benefits linked to the administration of a variety of low-risk intermittent hypoxia protocols.

Fitness and therapeutic potential of intermittent hypoxia training: a matter of dose

“…Some characteristics of different regimes are described in recent reviews [4,5,7,8,12,13]. Historically, first methodical recommendations for IHT implementation in human practice were published by the Russian Health Ministry in 1988 which recommended the inhalation of 10-12% O 2 during 5-min periods with 5 min rest, 1 h per session, 1-4 weeks per course for the treatment of various diseases.…”

“…Mechanisms of maladaptive responses are very good described in recent reviews [6,54,62,71,72, and many others]. Studies in this field have led to the view that intermittent hypoxia is the principal, if not the only, risk factor for the development of a number of detrimental cardiovascular, respiratory, metabolic, and cognitive outcomes [7]. The authors having analyzed a large number of studies concluded that protocols that were employed to establish the link between intermittent hypoxia and detrimental outcomes were typically severe in regards to intensity, duration, or both.…”

“…This topic is the subject of many articles, reviews and monographs. To avoid repetition we refer readers to the most recent reviews [3][4][5][6][7][8][9][10].…”

“…The biological responses to intermittent hypoxia may be adaptive or maladaptive, depending on the severity of the hypoxemia, its frequency of occurrence, its duration, and, importantly, the "pattern" and timing of each of the HbO 2 desaturation/ resaturation cycles [7,11]. Many types of protocol with different numbers of hypoxia episodes, severity, and total exposure duration have been used by investigators, and these combinations may have resulted in various physiological responses.…”

Intermittent hypoxia training in prediabetes patients: Beneficial effects on glucose homeostasis, hypoxia tolerance and gene expression

“…The mechanisms underlying the beneficial effects of IHT have been investigated at the multiple biological levels, from systemic physiological reactions to genomic regulation. [1][2][3][4][5] The potential therapeutic uses of IHT in treating cerebrovascular and cardiovascular disorders have been the focal areas of extensive research. 6,7 Despite these advances, the effects of IHT on diabetes mellitus, especially type 2 diabetes, one of the most prevalent pathological conditions in the current world population, are much less investigated.…”