[CORRECTION OF HEART RATE VARIABILITY USING DIAPHRAGMATIC BREATHING MODE BIOFEEDBACK IN HEALTHY PEOPLE.]

The research is an attempt to explain the use of portable computer devices aiming to correct heart rate variability (HRV) of healthy young men. According to the data, used deep diaphragmatic breathing in mode of biofeedback harmonizes breathing and blood circulation which positively affects the body's adaptive potential. However, developers present the portable instruments of biofeedback primarily as a means of psychological relaxation. The aim of this study is to determine whether such devices are able to significantly affect heart rate variability and how long this effect lasts. There were 30 males aged 18 to 20 years that participated in this study. They were randomly divided into three equal groups with up to 10 people in each of them. Members of the first group were doing breathing exercises using a portable biofeedback StressEraser device, the second group used Em-Wave2, and the third one used hardware and software system MyCalmBeat. Each session lasted from 10 to 15 minutes. There were 10 sessions held daily in the morning. HRV was recorded by remote heart rate monitor Polar RS800CX and software Polar ProTrainer5. 5-minutes' stationary segments of the curve chest electrocardiogram removal were used in order to calculate the HRV indexes. It was found that 15 minutes deep breathing in mode of biofeedback significantly affects the heart rate variability of healthy young people. In particular, it increases the overall heart rate variability according to the statistical and spectral analysis. It was established that in all 3 groups of experiment participants the spectral curve low-range "Low frequency" (LF) suffered the major shifts. These shifts reflect the activity level of the sympathetic autonomic nervous system (ANS) as well as vascular-motor center according to the conventional interpretation. It was found that all three groups suffered a specific weight decrease of Very Low Frequency (VLF)% respectively 11.8±2.2%;(p <0,01); 6.6 ± 2.8%; (p <0,02) and 6.8 ± 2.4% (p <0,05). This means that activity redistribution between different regulatory components of heart rate occurred in favour of the peripheral ANS parts. Heart rate variability changes of this kind remained valid for at least one month after the experiment. The greatest influence on heart rate variability was observed in the group of people who used the device StressEraser.