How does the physiological sigh work?

The physiological sigh is a breathing pattern that significantly aids in oxygen intake and carbon dioxide expulsion, thereby helping to rapidly reduce stress levels. It involves a double inhale followed by a long exhale. The first deep inhalation is followed by a shorter, supplemental inhalation, which fully inflates the lungs' alveoli, the tiny sacs involved in gas exchange. This process increases lung efficiency and the long exhale that follows helps expel accumulated carbon dioxide.

The effectiveness of the physiological sigh is supported by its impact on the autonomic nervous system, balancing the sympathetic ("fight or flight") and parasympathetic ("rest and digest") responses. By reintroducing balance between these systems, it brings a rapid sense of calm, useful particularly in stress-inducing situations 1 2.

Physiological sighs are not just a modern technique; they were initially discovered by physiologists in the 1930s and are a natural response of the body to high levels of carbon dioxide in the blood 3. They can be used effectively in real-time for quick relaxation and stress management.