Adaptation of functional systems in different generations of Caucasians in the North-East of Russia

Abstract

BACKGROUND: A substantial body of research has focused on adaptation of the new residents of the European and Asian Far North. However, these publications fail to address the changes occurring in successive generations of native Caucasians who migrated to the regions with harsh climatic conditions.
 AIM: To study functional adaptations exhibited by individuals born in the Magadan Region to various generations of Caucasians permanently living in the area.
 METHODS: A total of 1632 male volunteers, all students aged 181.1 years, and of Caucasian ethnicity, participated in this study. These individuals were either migrants or residents of Russia's North-East, born within the first to third generations. We investigated anthropometric characteristics, cardiohemodynamic parameters, and gas exchange to understand the adaptive readjustments that take place within the body's functional systems.
 RESULTS: Migrants and first-generation residents in the Magadan region experience constant stress and inadequate functioning of their cardiohemodynamic and energy exchange systems under extreme conditions. However, the third-generation subjects exhibited optimal performance of the cardiovascular system. Remarkably, the third-generation residents demonstrate an increased systolic volume at lower arterial pressure and lower total peripheral resistance. Furthermore, they had elevated proportion of the high frequency component and total power of the heart rhythm spectrum. This represents a new level of changed influence on the heart rhythm, as seen in the altered balance of its statistical and spectral wave characteristics. Moreover, the adaptability of the cardiovascular system to the harsh conditions of the North is reflected not only in the physiological indicators of the body but also in the integral structure of their correlations. This includes the magnitude and sign of the correlation coefficients and their significance.
 CONCLUSIONS: Our main findings suggest that adaptive changes in cardiohemodynamic and gas exchange exhibited by the migrants and several generations of residents of the Far North-East of Russia are directed to minimization of the total energy expenditure in functional systems. Additionally, the parasympathetic contribution increases fostering a novel interaction between the components of autonomic nervous regulation reflected by both qualitative and quantitative alterations in the structure and patterns of correlation clusters. These findings contribute to our understanding of the physiological mechanisms behind the morphofunctional readjustments of Caucasian men in the process of adaptation to the harsh climatic conditions of the Russian North-East.