Heart Rate Variability in Children of Younger School Age during Speleoclimatotherapy

The autonomic nervous system is a key link in the course of adaptation and adaptive reactions of an organism to various environmental factors. The aim of this study was to assess the heart rate variability (HRV) of primary school children during a course of speleoclimatotherapy. The HRV was evaluated in 175 practically healthy children aged 7–10 years. In the course of the study of the effect of speleoclimatotherapy on the balance between the sympathetic and parasympathetic nervous system was studied using the parameters of spectral analysis of HRV. HRV data were analyzed in the frequency domain: total power of the wave (TP), high frequency (HF) waves, low frequency (LF) waves, very low frequency (VLF), and vagosympathetic index LF/HF. After a course of speleoclimatotherapy the analysis of the results allowed us to establish statistically significant differences in the groups of boy and girls with vagotonic and normotonic type of regulation. After a course of speleoclimatotherapy reduction of the index of a vagosympathetic balance (LF/HF) to normal values was found in the groups of sympathotonic boys and sympathotonic girls, while in sympathotonic girls there was an increase in the value of the TP. It is possible to speak about the restoration of vegetative equilibrium and increase of adaptive capabilities of a child due to adaptation to the microclimate of speleo-chambers.