CHANGES IN HEMODYNAMICS, GAS EXCHANGE AND HEART RATE VARIABILITY AMONG YOUNG CAUCASIAN MEN UNDER RE­BREATHING: PART 2

Introduction: Studying physiological mechanisms of resistance to the effects of extreme environmental factors on the human body is on the top of research agenda related to active development of the Arctic regions of Russia. Aim: To assess changes in hemodynamics, gas exchange and heart rate variability during re-breathing among young men from the continental and coastal areas of North-Eastern Russia. Methods: In total, 271 young men aged 17-21 years with different resistance to hypoxic-hypercapnic exposure and who are permanent residents of the continental (Susuman) and coastal (Magadan) zones of the Magadan region participated in a cross-sectional study. Physiological parameters were estimated using "VARICARD" device, tonometer and "NPK Carbonic" gas analyzer. Results: We present the difference in oxygen levels at rest and during re-breathing taking into account correlations in the clusters. This analysis allowed us to propose an empirical formula for calculating the degree of allostatic adaptive load (AL) experienced by the body of a young male Caucasian born in the Far North-East of Russia. Residents of Magadan had AL values of 20.2 and 55.8 units for high- low resistant individuals, respectively. The corresponding values for Susuman residents were 26.5 and 55.9 units. Conclusion: Greater values of AL for high resistant residents of the continental area compared to the residents of the coastal zone may be explained by climatic factors. In addition, low resistant continental residents have AL twice as high their high resistant counterparts. As for low resistant subjects, no difference was observed in the AL values across the areas. Our approach with readjustments in hemodynamic, heart rate and gas analysis as well as with the structures of correlations in the intersystem clusters can provide quantitative assessment of the severity of climatic effects in the process of adaptation of humans to environmental extremes.