What is the cyclic physiological sigh?

The cyclic physiological sigh is a breathing technique discussed by Andrew Huberman that involves performing a sequence of deep breaths to manage stress, improve mood, and enhance sleep. Here’s how it works:

1. Double Inhale: You start with a deep inhale through the nose, followed immediately by a shorter, second inhale—a method that helps to maximally inflate the lungs.
2. Extended Exhale: After the inhales, you proceed with a long exhale through the mouth, emptying the lungs completely.

This sequence is repeated cyclically for about five minutes, regardless of the time of day. By engaging in this practice regularly, individuals experienced notable improvements not only during the breathing exercise but also in their general daily stress levels and sleep quality. The cyclic physiological sigh was found to be the most effective compared to other breathing practices like box breathing or mindfulness meditation, in reducing stress and enhancing autonomic function as measured by improvements in heart rate variability and other physiological metrics 1 2.