Abstract
BACKGROUND: Dysfunctional breathing patterns may impair autonomic regulation and increase perceived stress. Breathing-based interventions, particularly those involving guided exercises and supportive tools, have the potential to provide non-pharmacological benefits. METHODS: In this parallel two-arm randomized controlled trial, 14 women aged 35-45 years with signs of dysfunctional breathing and no comorbidities were recruited from a fitness club. Participants were randomly assigned (1:1) using a computer-generated sequence to an intervention group (n = 7) or a control group (n = 7). Blinding was not applied. Both groups completed a 6-week program of guided breathing exercises using the iBreathe app, while the intervention group additionally used mouth tape during sleep. The primary outcomes were heart rate variability (HRV) indices-root mean square of successive differences (RMSSD) and the high-frequency (HF) component. Secondary outcomes included respiratory rate, Hencho test performance, and perceived stress measured using the Perceived Stress Scale-10 (PSS-10) and a Visual Analogue Scale (VAS). All participants were included in the final analysis (no loss to follow-up). RESULTS: The intervention group showed a significant increase in the HF component of HRV (p = 0.018) and improved Hencho test performance (p = 0.018). Both groups demonstrated significant reductions in respiratory rate (p < 0.05) and PSS scores (p < 0.05). Between-group differences were not significant for RMSSD or perceived stress. No adverse events were reported. CONCLUSIONS: A 6-week breathing intervention improved respiratory efficiency and reduced perceived stress among women with dysfunctional breathing. The additional of night-time mouth taping provided further benefits for HRV and respiratory control. Larger and longer trials are needed to confirm these findings.