Mountain climate is greatly beneficial for human health. Long-living healthy elderly persons pursuing an active lifestyle are often found in the middle-height mountains, rather than anywhere else.

At arrival in altitude locations higher than 2500 - 3500 m., many persons experience respiratory distress, dizziness, general fatigue, and rapid heartbeat to a varying degree. This set of symptoms is a well-known “altitude illness”, which normally rapidly resolves during return to sea-level.

But when travelers or mountain-climbers stay in altitude longer than two weeks, then upon return to sea level they usually experience uncommon energy surge, a feeling of joy and euphoria. Why it happens?

Ever since one was at school, we know about the significant effect of the oxygen content on vital functions of a human body. Upon climbing at height of 4500—5000 m, oxygen content in the inhaled air drops down to 10—12 %, and then, during return back to sea level, oxygen content goes up to 20.9%. 

Scientists conducted numerous studies on influence of reduced oxygen content (hypoxia) in the inhaled air on human body. Results of studies show that hypoxia in general is a dramatic stress-factor for a human. But such stress can provide beneficial adaptations, if applied properly. Thus, a controlled intermittent hypoxia improves oxygen absorption in the lungs, enhances oxygen-carrying blood capacity and increases efficiency of oxygen utilization in cells. Moreover, there are numerous biochemical and structural adaptations develop, which facilitate cellular and tissue resistance to multiple damaging factors, such as poisoning, extremely high and/or low temperatures, irradiation and mechanical damage.

Positive effects of simulated “mountain air” on human body develop at oxygen content range from 16 to 10%, which corresponds to altitudes 2000 to 6000 m. Remarkably, that the intermittent pattern of oxygen oscillations from 10% (hypoxia) to 21% (normoxia, sea level) and even 40% (hyperoxia) most efficiently activates preinstalled in our genes numerous adaptation responses.