[Ecology, adaptation and biorhythms]

The interfusion of environmentology and chronobiology makes it possible to explore various physiological mechanisms which arose in the process of evolution as a response to the external challenges. Therefore, a living organism adapts to a changing situation on the environmental and evolutional time scale. Since the temporal structure of environment is rhythmic by nature, body parameters may be strongly dependent on the environmental factors during adaptation. Results of the in-depth environmental and physiological studies of representatives of different climatic-geographical regions pointed to a series of common and individual properties of the human body reaction to an environment. The combination of hypoxia and hypercapnia (rebreathing test) brought into light a relationship of the reciprocal reaction of respiration and circulation to the body mass index and the average annual temperature in a region. The higher the temperature, the lower the body mass index, the weaker the hemodynamic reaction and the more expressed the ventilatory reaction.