Periodic Hypoxia: Physiological Effects and Possible Molecular Mechanisms

Periodic hypoxia includes periods of low oxygen content, interspersed with periods of reoxygenation. Periodic hypoxia is usually associated with pathological conditions and is considered as a negative stimulus leading to disorders of cognitive functions, the cardiovascular system, respiration and metabolism. It is the most important pathophysiological element of sleep apnea syndrome, which is accompanied by the development of inflammation and oxidative stress. On the other hand, periodic hypoxia, unrelated to sleep apnea, has a positive or negative effect on the body, depending on the intensity, duration and number and frequency of hypoxic exposures. In medicine, periodic hypoxia is used to improve health and enhance performance and is a non-pharmacological treatment for a number of diseases. The goal of the present review is to summarize clinical and experimental data on the effect of periodic hypoxemic hypoxia on the adult body. Special attention is paid to the effect of periodic hypoxia on cognitive functions. The review discusses the molecular mechanisms by which periodic hypoxia can trigger a cascade of intracellular reactions leading to either beneficial or pathological effects