PhD V.F. Volkov¹
Dr.Med. A.V. Kalinin²
PhD Yu.V. Shuliko²
V.A. Pokhachevsky^3
1Sechenov First MSMU, Moscow
²Lesgaft National State University of Physical Education, Sport and Health, St. Petersburg
³Lomonosov MSU, Moscow

Key words: physical activity tolerance, price of adaptation.

Introduction. The price of adaptation is the most important indicator that determines the formation of fitness and prevention of overload. Question its objective control in the process physical coaching received remains open.
The aim of the study was to determine the physiological cost of physical activity (FN) by heart rate variability (CP) of the recovery period.
Methodology and organization of the study. The first group of active athletes was examined-22 people: MMC, MS (middle distance), 10 of them are engaged in athletics, 12-cross-country skiing; the second group consisted of representatives of unsportsmanlike youth, 18 of them are not engaged in systematic physical exercises.
Maximum Bicycle ergometric testing (e-Bike Ergometer) was carried out according to an individual Protocol. From the digitized (Polispectr-12, Neurosoft) electrocardiogram of the entire testing time, a sequential series of RR intervals (cardiointervals-CI) – cardiorhythmogram – was distinguished. Computing and statsremote was carried out by standard packages Excel and Statistica 6.0.
The results of the study and their discussion. Pnnx is the percentage of pairs of CI with a difference Of x MS or more to the total number of CI in the array. Since the value of the absolute difference of neighboring CI does not exceed 15 MS in median, pNN5, 10 and 15 were studied.
The variability of pNN5-15 markers in group 2 fluctuates at the minimum level with a slight increase in the 2nd min (only pNN5) and a drop to zero on the 3rd; in group 1 it is characterized by pronounced progressive dynamics for all markers. Areactivity in group 2 is due to a long period of myocardial refractoriness, when the latter can not respond to regulatory effects due to overload.
Despite the significant dominance of the transferred load in the group of athletes (more than 3 times: 60-90 W vs. 210-270 W), the recovery rate also prevails. The 2nd group is characterized by the inversion of connections, positive values of which are replaced by negative ones-by 2 and 3. In this case, the positive values are initially due to the arrhythmic component, showing overload phenomena. The negative correlation of indicators, which determines the correspondence of greater load tolerance to less SR variability, is a normal physiological reaction, implying the need for a longer period to restore myocardial sensitivity to inhibitory regulatory influences.
Conclusion. The high level of endurance is due to the feedback of the pNNx level with the power of the transferred load. In this case, the relationship is weakened in time and is maximum at 1 min.
The presence of pathophysiological-arrhythmic markers on the 1st minute of recovery indicates the failure of adaptive reactions in the group of unsportsmanlike youth.
The prospect of practical application of these markers is associated with early diagnosis of the cost of transferred FN, prevention of overload and overtraining consequences.

References

1. Lapkin M. M., the Value of the variability of R-R intervals during the exercise testing / M. M. Lapkin, A. L. Bohachevsky // human Physiology. - 2017. - No. 1 (43).  Pp. 81-88.
2. Puhacheuski A. L. a Temporal analysis of R-R intervals for load testing / A. L. Bohachevsky // Pathological physiology and experimental therapy. - 2011. - No. 2.  Pp. 34-40.