PHOTOPERIODIC STABILITY AND DISTRIBUTION OF CHRONOTYPES IN YOUNG RESIDENTS OF THE NORTH WITH DIFFERENT ORGANIZATION OF ACTIVITIES

Objective: to assess individual subjective chronotypic properties in residents of Khanty-Mansiysk under the influence of such biotropic and social stress factors as regular daytime and aperiodically presented shift daytime and nighttime employment. Methods. The study involved students of Khanty-Mansi Autonomous Okrug-Yugra with a daily study load, 100 girls and 53 boys, and employees of the "Ambulance" station in Khanty-Mansiysk, working in shifts, 31 women and 26 men The photoperiodic chronotype stability was studied using the computer program Photoperiodic chronotype stability calculator (registration no. 2019661664) in the form of a mobile application for Android Photoperiodic stability index. Results. The photoperiodic stability of the chronotype in women is: with regular daily employment - 3.5 (1.50-6.00) arb. units, with night shift work - 1.0 (0.00-4.00) arb. units; for men: with regular daily employment - 3.0 (1.00-4.00) arb. units, with shift night work - 1.5 (0.00-3.00) arb. units Volunteers with a regulated daytime job gravitated toward choosing to shift activities to the afternoon and refusing morning activity. In the group with shift work, the proportion of people oriented toward the morning type of work capacity was increased. In the group with shift and night work, there were no representatives of a definitely morning chronotype among women, and definitely an evening chronotype among men. In the summer season, male and female respondents, regardless of the production regime, showed an increase in the signs of the morning chronotype. Conclusion. The production and intersexual features of the chronotypological properties of the inhabitants of the North have been established. With the superposition of extreme climatic and geographical factors and social and production conditions, a general pattern of increased rigidity of the chronotype is revealed. Male and female respondents with different production regimes, when assessing subjective biorhythmic performance in the summer, demonstrate a shift towards the morning chronotype.