MULTICHANNEL EEG, respiration, blood pressure and ECG were recorded du
ring paced breathing at five frequencies in 18 subjects in order to el
ucidate the effects of paced breathing on power changes in alpha, beta
and theta bands, and on rhythmical variability of these parameters. M
ean power in the beta band and low-frequency beta power variability (0
.12-0.04 Hz) increased during paced breathing at frequencies of 0.25 a
nd 0.20 Hz. The total variability of alpha power in the right parietal
and occipital electrodes decreased during paced breathing at 0.1 Hz c
ompared with initial rest. The results point to increased cortical exc
itability during paced breathing at eupnoeic frequencies and to dimini
shed cortical sensitivity to desynchronizing influences during paced b
reathing at 0.1 Hz.