The Cyclic Sigh (Single-Cycle)

A single, intentional breathing pattern to downregulate the nervous system and clear the alveoli.

Physiological Sigh · Andrew Huberman (Stanford University), Jack Feldman (UCLA) · Acute stress, anxiety, overwhelm, desire for rapid relaxation or mental clarity. · Perform 1-3 cycles as needed. For acute stress, a single cycle can be sufficient. For deeper relaxation, repeat up to three times consecutively.

Why it works

The physiological sigh, characterized by two inhales followed by a prolonged exhale, is a hardwired reflex in mammals for resetting breathing patterns and reducing stress. The double inhale fully inflates collapsed alveoli in the lungs, maximizing oxygen exchange. The extended, slow exhale activates the parasympathetic nervous system via the vagus nerve, signaling safety and promoting relaxation. This mechanism shifts the body from a state of sympathetic arousal (fight or flight) to parasympathetic dominance (rest and digest).

How to practice

1. Find a comfortable seated or reclined position.

2. Inhale deeply through your nose until your lungs feel moderately full.

3. Without exhaling, take a second, short, sharp inhale, drawing in a bit more air, filling the very top of your lungs.

4. Slowly, and completely, exhale through your mouth with a soft "whoosh" sound until your lungs are empty. Focus on releasing all tension with the exhale.

5. Find a comfortable seated or reclined position.

6. Inhale deeply through your nose until your lungs feel moderately full.

7. Without exhaling, take a second, short, sharp inhale, drawing in a bit more air, filling the very top of your lungs.

8. Slowly, and completely, exhale through your mouth with a soft "whoosh" sound until your lungs are empty. Focus on releasing all tension with the exhale.