Poor posture impedes breathing

Source: physio-pedia.com (from introduction to an online course aimed at medical personnel)

• Posture has a significant impact on the function of the diaphragm.
• In order to optimize diaphragmatic function, vertical length is required — the thoracic and abdominal cavities need to be long enough for the diaphragm to create negative and positive pressure during inspiration and expiration.
• Postural dysfunctions such as forward head reduce the strength and mobility of the diaphragm, thus impeding breathing.