Cardiohemodynamic Response to Local Cold Exposure Among Men From Coastal- And Inland Zones of the Magadan Region

Aim: To study the changes in cardiodynamics experienced by humans under local cold exposure in coastal- and inland areas of the Magadan region, North-Eastern Russia. Methods: In total, 124 residents from the coastal area (Magadan) and 62 residents from the inland area (Susuman) took part in the experiment. Parameters of heart rate and hemodynamics at rest and at the peak of a cold test were estimated using "Varicard" device and a tonometer. Results: At rest the examinees from the continental zone demonstrated a less economical mode of the circulatory system functioning with a simultaneous decrease in sympathetic activity and the transition of the autonomic balance towards parasympathetic predominance. That is considered a regional-related feature of the functional status of the cardiovascular system when adapting to more extreme environmental factors. Such features of cardiohemodynamics could be observed against the background of an increase in basal metabolic rate by 17 % in subjects from Magadan and 31 % in those from Susuman. The short-term cold exposure caused a hypertensive response in both groups. The subjects from the continental area showed a more pronounced vasoconstriction, which was combined with a decrease in the activity of the parasympathetic link in the heart rhythm regulation, while the Magadan subjects demonstrated the opposite reaction to the cold test which led to the activation of the parasympathetic link of the ANS. Conclusion: The results that the residents of the coastal areas develop the reaction of getting used to the influence of the cold factor, with a slightly pronounced metabolic adaptation Young residents of the continental zone, in response to the effects of cold, develop an isolation type of cold adaptation with sufficient activation of metabolic adaptation.