Diaphragmatic Breathing and Stimulation of the Autonomic Nervous System

Introduction: Slow, deep breathing has demonstrated beneficial effects on the autonomic nervous system, particularly by increasing parasympathetic activity through vagal nerve modulation. Previous studies suggest that this breathing pattern optimizes the sympathovagal balance, modifies physiological parameters such as heart rate, blood pressure, and oxygen saturation, and influences variables including heart rate variability (HRV) and RR intervals. Objectives: To analyze the effects of different slow deep breathing (SDB) training modalities on vagal tone regulation. Secondary objectives include evaluating their impact on heart rate and rhythm, HRV, cardiac beat intervals, blood pressure, and oxygen saturation. Methodology: A randomized, controlled, single-blind, parallel-design clinical trial will be conducted. Sixty healthy participants will be enrolled and allocated into three groups: two experimental groups (SDB with and without apnea) and one control group (breathing education). Pre- and post-intervention measurements will include HRV, RR intervals, heart rate, blood pressure, oxygen saturation, and cervical joint variables. Data will be analyzed using repeated-measures ANOVA and statistical tests appropriate for each variable type, with a significance level set at 5%. Expected Results: SDB-based interventions are expected to produce significant improvements in vagal regulation, increasing heart rate variability and favorably modifying the aforementioned physiological parameters compared with the control group.

Inclusion Criteria: * Healthy individuals who have not smoked during the 24 hours prior to the study. * Healthy individuals who have not drunk alcohol during the 24 hours prior to the study. * Healthy individuals who have not drunk coffee during the 24 hours prior to the study. Exclusion Criteria: * Individuals with cardiovascular diseases or neurological disorders. * Individuals with cognitive impairment. * Individuals taking medications that affect autonomic nervous system function, such as: benzodiazepines, beta-blockers or beta-adrenergic agents.