CIRCADIAN RHYTHMS OF HEART RATE OF ATHLETES FROM DIFFERENT SPORTS EXPERIENCING INTENSIVE TRAINING LOADS IN MIDDLE MOUNTAIN REGIONS

The aim of the research: to identify the characteristics of resynchronization and synchronization of circadian (daily) rhythms of elite athletes when adapting to intensive training loads in middle mountain regions. Materials and methods. The studies were carried out at the Center for Biomedical Technologies of The Federal State Budgetary Institution «North Caucasian Research and Clinical Center under the Federal Medical Biological Agency» in Kislovodsk on the Maloe Sedlo [Small Saddle] Mountain at an altitude of 1240 m in terms of training camps for athletes. The study was focused on the investigation of parameters of circadian rhythms of heart rate, cardio-respiratory system parameters, and heart rate variability of 360 elite athletes. Results and discussion. The study revealed accurate 24 hours heart rate rhythms, which indicates an obvious rhythmicity and the absence of desynchronosis. The rhythm parameters of athletes in various sports differed significantly. The amplitude of the circadian rhythms is mostly determined by the level of motor activity. Acrophases of the circadian rhythms of the heart rate of athletes were recorded during the period from 13 to 17 h. Earlier acrophases, as a rule, were accompanied by a larger amplitude and a higher circadian rhythms mezor. The study of circadian rhythms of athletes with symptoms of latent desynchronosis showed that they had obvious daily rhythmicity but different circadian rhythms parameters of the heart rate: mezor, amplitude, acrophase. Large values of mezor and amplitude of spread of circadian rhythms of heart rate were found in athletes with high blood pressure and stress index, while smaller values were found in athletes with low blood pressure and hypoxia. Conclusion. Intensive training loads and extreme environmental conditions do not cause disturbance of the rhythm of the body functions of elite athletes. Moreover it contributes to the manifestation of a larger range of functions. The strain of adaptation processes of athletes, detected by abnormal physiological indices is reflected in the parameters of rhythms during the adaptation to the middle mountain environment.

1. Agadzhanian, N.A. L. I. Ignatiev, I. V. Radysh [The influence of natural and climatic factors of Kislovodsk on the blood system in different seasons] Khronobiologiia i khronomeditsina: Rukovodstvo [Chronobiology and chronomedicine: Handbook]. Moscow, OOO Medical Information Agency Publ, 2012. pp. 191-205.
2. Agadzhanian, N.A., Radysh I. V. Bioritmy, sreda obitaniia, zdorove [Biorhythms, habitat, health]. Moscow, RUDN Publ., 2013. - 362 p.
3. Aliakrinskii, B.S. Zakon tsirkadiannosti i problema desinkhronoza [Circadian law and the problem of desynchronosis] Problemy khronobiologii, khronopatologii, khronofarmakologii i khronomeditsiny [Problems of chronobiology, chronopathology, chronopharmacology and chronomedicine]. Ufa, BGMI Publ., 1985. - vol. 1, pp. 6-7.
4. Koriagina, Iu. V., Nopin C. V., Blinov V. A., Blinov O. A. [Development of automated systems for diagnostics and analyzes of various components of athlete’s fitness] Teoriia i praktika fizicheskoi kultury [Theory and practice of physical culture]. 2015, no. 8, pp. 101-104.
5. Salova, Iu. P., Koriagina Iu. V. [Daily rhythmicity of parameters of the systems of vegetative support of skiers-racers] Lechebnaia fizkultura i sportivnaia meditsina [Therapeutic physical training and sport medicine]. 2011, no. 8, pp. 21-26.
6. Halberg F. [Some aspects of biological data analysis and transverse profiles of rhythms Circadian clocks]. Amsterdam etc., 1965,  pp. 675-725.