Why does exhaling calm you

Exhaling can trigger a calming response in the body, according to Andrew Huberman. During deliberate slow breathing, or down-regulation breathing, actively exhaling emphasizes the calming response in the brain and body. When we ordinarily breathe, we inhale actively and exhale passively; slow deliberate breathing requires actively exhaling, which is associated with calmness. Emphasizing exhales can be done through techniques like physiological sighs or simply by noticing and prolonging the exhales more than the inhales 1.

Regarding the physiological basis, Dr. Huberman explains that when you exhale, the diaphragm moves up, causing the heart to get smaller and blood to move faster. This signals the brain to slow the heart rate down. Therefore, emphasizing exhales longer than inhales generally results in calming the system by slowing the heart rate 2. This physiological sigh has been shown to offload carbon dioxide effectively and relax the body quickly 3.

This practice is an example of how breathing techniques can regulate the autonomic nervous system and promote a sense of calm.