ORIGINAL ARTICLES   

Gazzetta Medica Italiana Archivio per le Scienze Mediche 2010 August;169(4):149-56

Copyright © 2010 EDIZIONI MINERVA MEDICA

language: English

Pattern of breathing speed responses to EEG and mood changes

Kim C. G.

Graduate School of Comprehensive, Human Sciences, University of Tsukuba, Tennoudai, Tsukuba, Ibaraki, Japan

Yoga mainly consists of postures (asana), breathing exercises (pranayama) and meditations. Among these techniques, breathing exercises is useful to practice in terms of mild intensity and doing without circumstance. Many studies have demonstrated effects of breathing exercises on physiologic parameters, but the fundamental mechanisms have not been clarified so far. Some factors are speculated as their effects, however, we will focus on a speed of breathing in this study. Therefore, this study aims to determine the effects of speed of breathing on electroencephalogram (EEG) as physiological parameter while the mood changes were tested using the two-dimensional mood scale (TDMS). To confirm the effect of the differences of breathing speed, three different speeds of breathing exercises were adopted: natural breathing (NB: approximately 12-15 breaths /min), slow breathing (SB: approximately 4 breaths /min) and fast breathing (FB: approximately 120 breaths /min) were performed by 10 healthy subjects for 10 minutes in an eye-closed condition on different days. Significant changes in the time course of alpha power during FB compared to NB at 3 min and 5-9 min, revealed significant increase at 5 min compared to SB. There were no significant difference in the effect alpha power in NB and SB. FB significantly improved on positive arousal level after and after 30min. As for NB and SB, there were no significant difference in the mood changes. Subjects had a feeling of positive tone with a tendency of increased modest arousal level, during and/or after FB. These results suggested that the increase in alpha power is considered to be linked to this state of positive tone. Furthermore, FB induce a increase of alpha power and positive arousal level. Since the volume of end-tidal carbon dioxide tension (ETCO2) significantly increased in SB, decreased in FB, we speculate that the change in ETCO2 may produce the changes in the EEG pattern.