Modulation of EEG by Slow-Symmetric Breathing Incorporating Breath-Hold

The interplay between the brain and lungs involves intricate physiological mechanisms operating bidirectionally. Volitional breathing, unlike spontaneous breathing, offers various benefits with potential therapeutic effects. Volitional breathing involves many variables, such as breathing rate (BR) and breathing patterns. The main objective is to study the neural dynamics during slow-symmetric breathing (SSB) at different rates, with and without incorporating breath-holds post inhalation and exhalation. Electroencephalogram (EEG) is analyzed from 63 healthy adults while breathing at 10, 6, and 4 cycles per minute (cpm) guided by a visual metronome. A significant increase in coherence is observed during SSB at all breathing rates and resonance at 6 cpm (0.1 Hz). We also study EEG band power changes, coupling of the breathing phase with EEG amplitude, and EEG modulation during SSB. The power in alpha and beta bands is significantly higher during breath-hold than during inhalation and exhalation. Compared to the baseline, the modulation index increases significantly during SSB, illustrating the enhanced modulation of brain activity. Interestingly, coherence, phase-amplitude coupling, and modulation index depend mainly on the breathing rate, and the differences between symmetric breathing with and without breath-hold are not statistically significant. The observed similarities in neural dynamics across different breathing patterns suggest that achieving very low breathing rates is feasible with symmetric breathing with breath-holds while retaining the reported benefits of slow breathing.