One method is to inhale deeply, pursing one’s lips and exhaling forcefully, as if blowing up a balloon. This is known as pressure breathing; physicians call it positive end expiratory pressure, or PEEP. Patients with emphysema or other breathing difficulties use this technique reflexively, and research shows that it improves gas exchange and prevents fluid buildup in the lungs. The pursed lips and forceful exhalation increase air pressure, which resuscitates the lungs’ air sacs, or alveoli, so they can expand, absorb more oxygen, and expel more carbon dioxide.
