Effects of Brief Breathwork Under a State of Cognitive Fatigue on Subjective Well-Being and Diaphragm Function: A Randomized Crossover Design.

Abstract

Previous investigations have identified the effectiveness of breathwork on both psychological and physical health for individuals under a resting state. However, there was no study investigating the effects of breathwork under a mentally-fatigued state. The purpose of this study was to examine the acute effects of breathwork administered after the induction of mental fatigue by a cognitive tasks on primary self-reported outcomes including positive and negative affect and self-reported stress indices, as well as on secondary physiological outcomes including diaphragm function and stress-related physiological responses. This study was employed with a randomized cross-over study design. Twenty healthy university students voluntarily participated in this study. Each of them performed a 20-min breathwork and control (quiet bed rest) condition following the Colour-Word Stroop Task (CWST) in a randomized sequence over two days separated at least by a week. Participants completed self-reported questionnaires for positive and negative affect and stress indices and underwent ultrasonographic assessments of the diaphragm function, saliva collection for cortisol and IgA, and heart rate variability assessments at baseline, pre-CWST, post-CWST, and post-intervention. The breathwork condition demonstrated significantly higher positive affect at post-intervention compared to the control condition (p = 0.021). Right hemidiaphragm excursion and left hemidiaphragm thickness at end-inspiration significantly increased from post-CWST to post-intervention in the breathwork condition. The breathwork condition appeared to improve positive affect and diaphragm function even under a mentally-fatigued state, compared to the control condition. These findings indicate that breathwork may serve as a simple, accessible, and practical strategy to enhance subjective well-being in a stressful environment and diaphragm function regardless of mental fatigue.