Hypoxia: good guy or bad guy?

摘要

The present issue of "Sleep and Breathing" provides several lines of evidence for beneficial applications of exposure to hypoxic environments. This seems to contrast with the general experience that hypoxia is a constant threat to the human organism throughout life. Multiple hypoxic situations may occur in health and disease, but mechanisms have developed to protect the human body and its vital organs from detrimental effects of hypoxia. As demonstrated by the articles in this issue of "Sleep and Breathing" the specific use of such mechanisms might even have the potential of preventive or therapeutic effects. Despite a wealth of research work, it is not well understood why sometimes hypoxia is harmful and sometimes beneficial. Types of exposures and individual responses to hypoxia are so multifaceted that much more systematic research will be necessary to find conclusive answers. Nevertheless, sometimes hypoxia is undoubtedly a bad guy as it is the case at very high altitude, in obstructive sleep apnea or in severe chronic obstructive, pulmonary disease (COPD) [1-3].