Cardiovascular regulation in female students of northern university during extreme photoperiod seasons

Objective. The aim of study was to assess the state of cardiovascular system in female students in the northern region during the seasons with extreme photoperiod. Design and methods. The study was conducted in Nizhnevartovsk, Khanty-Mansi Autonomous Okrug-Yugra (a region equated to the Far North) in the seasons with extreme values of photoperiod. The female students of Nizhnevartovsk State University (n = 73) aged 18-21 years were examined. Anthropometric measurements were carried out. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were recorded automatically using UA-101 model tonometer. Pulse and mean dynamic pressure were calculated according to Hickam's formula. On the basis of HR we determined the average duration of cardiac cycle. Autonomic tone was assessed according to calculated Kerdo index (KI). We used CardioVisor-06c to determine the prenosological state of cardiac activity. Results. There was a significant increase in body weight in the short daylight period. The HR during the long daylight period was significantly higher than during light deprivation, leading to a shorter cardiac cycle duration. Seasonal dynamics of blood pressure characteristics were not evident, although during “white nights” at least 10 % female students had SBP higher than 130 mm Hg, and maximal SBP reached 135 mm Hg. KI values demonstrated significant changes in autonomic tone. During short daylight hours average characteristics of KI were negative and reflected activity of parasympathetic activity. Increase of sympathetic influences was during longer daylight hours. During “biological twilight” “Myocardium” index was significantly lower than during white nights. During short daylight hours only 10 % students showed “Myocardium” index over normal values (15 %), while half of respondents had higher values during white nights. “Rhythm” index was normal during the short daylight hours and significantly higher during the long daylight hours, only 10 % participants had normal values. Conclusions. The analysis of electrophysiological parameters of myocardium showed seasonal changes in female students and “white nights” were associated with more negative effects than “biological twilight”. During “white nights” we showed increase in integral indices of dispersion mapping, increase in resting HR and KI.

1. Zagorodnikov GG, Korovin AE, Mironov VG, Zagorodnikov GN, Tovpeko DV, Churilov LP. Basic hematological and metabolic blood parameters of flight personnel at different terms of service in the Arctic. Biosphere. 2019;11(4):211-226. In Russian.

2. Kubushka ON, Gudkov AB, Labutin NY. Some reactions of the cardiorespiratory system in young subjects during adaptive stress of relocation to the North. Human Ecology. 2004;5:16-18. In Russian.

3. Khimikova OI, Tretyakova ON, Blinov AV, Efremov DS, Palamarchuk AS. Results of studies of functional indices of the cardiovascular system of the human body in the North. Bulletin of the New Medical Technologies. 2013;1:103. In Russian.

4. Morgol AS, Yankovskaya LV. The association between vitamin D and myocardial structure and function in congestive heart failure. Arterial'naya Gipertenziya = Arterial Hypertension. 2016;22(2):169-176. doi:10.18705/1607-419X-2016-22-2-169-176. In Russian.

5. Karonova TL, Andreeva AT, Zlotnikova EK, Grineva EN. Vitamin D deficiency and arterial hypertension: what is common? Arterial'naya Gipertenziya = Arterial Hypertension. 2017;23(4):275-281. doi:10.18705/1607-419X-2017-23-4-275-281. In Russian.

6. Shurkevich NP, Vetoshkin AS, Gapon LI, Diachkov SM, Gubin DG. Prognostic value of blood pressure circadian rhythms disturbances in normotensive shift workers of the Arctic polar region. Arterial'naya Gipertenziya = Arterial Hypertension. 2017;23(1):36-46. doi:10.18705/1607-419X-2017-23-1-36-46. In Russian.

7. Kuzmenko NV, Pliss MG, Tsyrlin VA. Relationship between the time of year and the development of vasorenal hypertension. Arterial'naya Gipertenziya = Arterial Hypertension. 2017;23(6):561-573. doi:10.18705/1607-419X-2017-23-6-561-573. In Russian.

8. Vetoshkin AS, Shurkevich NP, Gapon LI, Gubin DG, Simonyan AA, Poshinov FA. The role of natural light rhythm in the development of desynchronosis in the conditions of rotational shiftwork in the Arctic. Siberian Medical Journal. 2019;34(4):91-100. doi:10.29001/2073-8552-2019-34-4-91-100. In Russian.

9. Ivanov GG, Bulanova NA, Nikolaeva MV, Shelikalina SP, Nikolaev DV, Khalabi G. The Myocardium micro-alternations index: the influence of gender, age and the frequency of normal values in screening examinations of the population. Medical Bulletin of Northern Caucasus. 2018;13(4):589-593. In Russian.

10. Computer-assisted cardiac screening system. “Cardiovisor”: methodological recommendations. MKS. KS 020001-64a. Moscow. 2008. 23 p. In Russian.

11. Khasnulin VI, Khasnulin PV. Modern concepts of the mechanisms forming northern stress in humans in high latitudes. Human Ecology. 2012;1:3-11. doi:10.17816/humeco17512. In Russian.

12. Cardiovascular prevention 2017. Russian national recommendations. Russian Journal of Cardiology. 2018;23(6):7-122. doi:10.15829/1560-4071-2018-6-7-122. In Russian.

13. Koposova TS, Chikova SN, Chikov AE. Adaptive capabilities of students during the «biological darkness». Human Ecology. 2007;1:50-54. In Russian.

14. Shalamova EY, Safonova VR, Ragozin ON. Intersex differences in diurnal variations of central hemodynamic indices in students of northern medical school. Human Ecology. 2016;7:26-30. In Russian.

15. Averin AS, Evtushenko ID, Mikheeva DY, Ivanova TV, Volkov RV, Menshikova NS et al. Changes in mean hemodynamic blood pressure in pregnant women with hypertensive syndrome. Siberian Medical Journal. 2010; 25(4-2):32-34. In Russian.

16. Sheveleva AM, Klauchek SV. Gender and age features of the daily blood pressure variations in healthy adolescents 12-17 years old. Bulletin of Volgograd State Medical University. 2017;4(64):108-111. doi:10.19163/1994-9480-2017-4(64)-108-111. In Russian.

17. Pogonysheva IA, Lunyak II, Pogonyshev DA. Annual dynamics of dispersion mapping indicators of electrocardiogram tracing in students with different chronotypes. Bulletin of Nizhnevartovsk State University. 2021;2(54):88-92.doi:10.36906/23114444/21-2/11

18. Bacevich VA, Krasilnikova VA, Permyakova EY. Adaptation capabilities of students from different districts of the Tyva Republic. Bulletin of Moscow University. Series 23: Anthropology. 2020;3:19-31. In Russian.

19. Lyamina NP, Malinova LI, Nalivaeva AV, Bisyaeva EA, Sentshikhin VN. Masked arterial hypertension in middle-aged working women: aspects of screening and prognosis. Kardiologiia. 2016;56(3):30-34. doi:10.18565/cardio.2016.3.30-34. In Russian.

20. Spitsin AP, Tsarev YK, Pershina TA. Indicators of central hemodynamics in undergraduate students depending on the activity of the parasympathetic part of the autonomic nervous system. Medical Science and Education of Ural. 2019;20(2):86-89. In Russian.