Slow-breathing intervention effects on resting brain activity and negative affective states in humans : a randomized controlled trial

The present study examined the effects of the Controlled Deep Breathing Technique (CDBT) on resting-state brain activity, emotional distress (negative affective states), and cognitive performance in healthy adults. Thirty-nine participants were randomly assigned to an experimental group practicing CDBT or a control group engaging in natural breathing. Resting-state EEG was recorded before and after the intervention under eyes-open and eyes-closed conditions, focusing on frontal and parietal alpha/beta power ratios. Subjective emotional distress and executive function (TMT-B) were assessed pre- and post-intervention. Results indicated a significant Group × Time interaction in alpha/beta ratios, reflecting a larger pre-to-post increase in the experimental group relative to the control group. Follow-up analyses suggested that the ratio increase in the experimental group was driven primarily by enhanced alpha power rather than reduced beta activity, and was descriptively more evident under eyes-closed conditions and over parietal regions. Behaviorally, the experimental group showed a reduction in DASS-21 total scores and faster TMT-B completion times from pre to post, whereas the control group showed minimal or smaller change patterns. Overall, these findings suggest that CDBT is associated with short-term modulation of resting-state electrophysiological markers and concurrent improvements in self-reported distress and executive task performance in a non-clinical sample. Given the brief, single-session intervention and the use of healthy participants, the results should be interpreted as preliminary and state-related rather than as evidence of definitive clinical efficacy. Further research using larger samples, longitudinal designs, and clinical populations is required to establish generalizability and potential applied relevance.