Physiological Sigh

The Physiological Sigh is a breathing technique popularized by neuroscientist Dr. Andrew Huberman. 

It mimics the natural breathing pattern our body uses during sleep or or after sobbing when it needs to lower the carbon dioxide levels in the bloodstream. This often happens under stress or when the amount of inhaled oxygen is insufficient. To perform the physiological sigh most effectively, inhale deeply through your nose until your lungs are full, then take a second, quicker breath without exhaling the first one. 

If you’re unable to breathe through your nose, two breaths - first long then a quick one - through your mouth can be used instead. Repeating this breath pattern three times helps regulate the nervous system, providing immediate relief in moments of stress. Additionally, incorporating it into your daily routine offers long-term benefits.

This exercise helps reduce stress and anxiety by activating the parasympathetic nervous system, which promotes relaxation. 

It can be used both in moments of stress or when anticipating stressful events, as well as incorporated into a daily routine to regulate the nervous system for long-term benefits

The Method

Here’s how the process works: The lungs contain small sacs called alveoli, which expand to take in oxygen. Under stress or when insufficient oxygen is inhaled, carbon dioxide levels rise, causing some of these sacs to collapse. The two consecutive breaths in this practice help to reinflate the alveoli, while the extended exhale allows the body to expel the maximum amount of carbon dioxide.

This technique also promotes heart rate variability (HRV), a key indicator of autonomic nervous system balance. Longer inhales speed up the heart, while slow, extended exhales slow it down, increasing variability in heart rate, which is beneficial for overall health and resilience.