Diaphragmatic breathing is a commonly taught practice to promote a relaxation response and reduce stress. In a study by Ma and colleagues, 40 healthy adults were randomly assigned to a diaphragmatic breathing group or a control group.1 Initially, all participants were instructed to focus on their breathing and the physical sensations produced in the body, while sitting comfortably in chairs with their eyes closed. Thereafter, the intervention group received 20-sessions over 8 weeks of an intervention involving instruction in diaphragmatic breathing and a 15-min resting breathing session followed by a 15-min diaphragmatic breathing session. The control group received no additional instruction. Both groups completed pre- and post- tests examining affect, sustained attention and cortisol levels, a stress hormone produced by the adrenal glands. A significant decrease in negative affect was observed in the intervention group while no change was observed in the control group. Both groups demonstrated a significant improvement in sustained attention compared to baseline. The intervention group also demonstrated a significantly lower cortisol level after training, while the control group showed no significant change in cortisol levels. This study suggests diaphragmatic breathing may contribute to positive physical and mental health measures in healthy adults.
1Ma X, Yue Z, Gong Z et al. The effect of diaphragmatic breathing on attention, negative affect and stress in healthy adults. Front Psychol. 2017 Jun 6;8:874.