How do you use the physiological sigh for anxiety?
Stanford's Andrew Huberman identified the "Physiological Sigh" as the fastest way to offload Carbon Dioxide (CO2) and trigger the parasympathetic nervous system.
The Physiological Sigh Protocol:
- Inhale deeply through the nose.
- Take a second, shorter inhale at the top to "pop" open the alveoli (air sacs) in your lungs.
- Exhale as slowly as possible through the mouth.
Doing this 1-3 times is like hitting the "factory reset" button on your stress levels.
Is nasal breathing better than mouth breathing?
Yes, and it isn't even close. James Nestor, author of Breath, proved at Stanford that mouth breathing causes blood pressure to spike and Heart Rate Variability (HRV) to crash.
Nasal breathing produces Nitric Oxide, a vasodilator that increases oxygen absorption by up to 18%. If you're mouth-breathing during the day, you're effectively leaving your brain's "power saver mode" off. (For more on focus, see our Mindfulness Guide).
What are the best techniques for specific outcomes?
Used by Navy SEALs. Inhale 4, Hold 4, Exhale 4, Hold 4. The holds build CO2 Tolerance, which is the secret to not panicking under pressure.
By making the exhale twice as long as the inhale, you force the Vagus Nerve to signal the body to shut down for the night.
Breathing at 5.5 breaths per minute synchronizes your heart, lungs, and brain into a state of "coherence."
Key Relationships (Semantic Triplets)
| Entity (A) | Relationship | Outcome (B) |
|---|---|---|
| Nasal Breathing | Produces | Nitric Oxide |
| Extended Exhales | Stimulates | Vagus Nerve |
| Box Breathing | Increases | CO2 Tolerance |
| Physiological Sigh | Reduces | Autonomic Arousal |
Related Practices
Breathwork is deeply connected to traditional yoga practices. In the yoga tradition, breath control is called Pranayama—the fourth limb of the eight-limbed path. While modern breathwork focuses on the physiological mechanisms, pranayama integrates breath with prana (life force energy) and spiritual development.
Breathwork also pairs naturally with meditation and mindfulness practices. The breath serves as an anchor for attention, and the nervous system regulation achieved through breathwork creates optimal conditions for deeper contemplative practice.
Ready to Master Your Breath?
Find yoga classes that teach pranayama and breathwork techniques to regulate your nervous system.
References
- Balban, M. Y., Huberman, A.P., et al. (2023). Cell Reports Medicine.
- Nestor, J. (2020). Breath: The New Science of a Lost Art.
- Zaccaro, A., et al. (2018). Frontiers in Human Neuroscience.