The reaction of blood microcirculation in the skin of various parts of the body after performing yoga breathing exercises

Abstract

Introduction. Yoga breathing exercises make it possible to change the minute ventilation (MV) within a wide range, reaching states of hyper- and hypoventilation with corresponding shifts in gas exchange. In this work, the interrelations between external respiration, parameters of gas metabolism and the skin microcirculation were evaluated. Materials and methods: 22 experienced volunteers performed yoga breathing exercises at a frequency of 3–3.5 times per minute and 1–1.5 times per minute for 5 minutes, as well as free breathing for 6 minutes before and after breathing exercises. Respiratory rate (RR), minute ventilation (MV), tidal volume (TV), partial pressure of CO2 in exhaled air at the end of exhalation (PetCO2), percentage of O2 in exhaled air (FeO2 ) were recorded using spirometry and gas analysis; by laser Doppler flowmetry and a distributed system of wearable analyzers parameters of skin microcirculation such as index of microcirculation (IM), nutritive blood flow (Imn ), amplitudes of endothelial (Ae), neurogenic (An), myogenic (Am), respiratory (Ar) and cardiac (Ac) oscillations were recorded in six body areas. Results. After the breathing exercises, the index of microcirculation of the supraorbital artery pool increased from 14.7 p. u. to 16.7 p. u., in the fingers from 24.8 p. u. to 29.4 p. u. and in toes from 8.2 p. u. to 10.2 p. u. with hypoventilation (RR=1–1.5 ­times/ minute) and in the skin of the supraorbital artery pool from 14.7 p. u. to 16.0 p. u., in the fingers from 27.1 p. u. to 29.8 p. u. and in toes from 11.5 p. u. to 13.5 p. u. with hyperventilation (RR=3–3.5 times / minute), nutritional blood flow increased from 14.4 p. u. and 14.3 p. u. to 17.8 p. u. and 16.9 perf.u. on the upper and from 4.7 p. u. and 6.1 p. u. to 6.8 p. u. and 7.5 p. u. on the lower extremities with hypo- and hyperventilation, respectively; an increase of the amplitude of endothelial blood oscillations after a hypoventilation and an increase of the amplitude of neurogenic oscillations after both types of breathing in the forehead skin were observed. Conclusion. The absence of differences between the effect of hypo- and hyperventilation exercises on Im suggests that the main mechanism of action may not be shifts in MV and gas exchange, but the depth of breathing; the influence of cognitive mechanisms (conscious control of breathing in both modes) is also discussed. The absence of changes in nutritive blood flow in the head can be explained by regional features of microcirculation regulation. The hypoventilatory mode of breathing significantly activates the endothelial mechanism of regulation; the neurogenic (sympathetic) mechanism of regulation is activated by both hypo- and hyperventilation respiratory modes.