Cyclic Sighing (Huberman Protocol) — Exercise & Movement
Double inhale through nose followed by extended exhale — shown in Stanford RCT to reduce stress more effectively than mindfulness meditation.
Overview
Cyclic sighing is a breathwork technique studied by Andrew Huberman's lab at Stanford, consisting of a double inhale through the nose (first deep inhale, then a shorter 'top-off' inhale to maximally inflate the lungs and open collapsed alveoli) followed by an extended exhale through the mouth. A 2023 Cell Reports Medicine RCT (n=108) compared 5 minutes daily of cyclic sighing against box breathing, cyclic hyperventilation, and mindfulness meditation. Cyclic sighing produced the greatest improvements in mood, anxiety reduction, and physiological markers including respiratory rate and HRV. The 'physiological sigh' occurs naturally during sleep and crying — this protocol deliberately harnesses the mechanism.
Indications
- Acute stress and anxiety reduction
- Autonomic nervous system calming
- Pre-sleep relaxation
- Mood improvement
- Respiratory rate reduction
Mechanism of Action
The double inhale maximally inflates the lungs, opening collapsed alveoli and maximizing the surface area for CO2 offloading
Dosing
| Compound | Dose | Frequency | Notes |
|---|---|---|---|
| Cyclic Sighing | 5 min (approx 20-25 cycles) | 1-3x daily | Most effective technique in Stanford 2023 RCT for stress reduction |
Evidence Grade
GRADE C
Safety & Contraindications
- Extremely safe; can be performed anywhere, anytime
- Extended exhales may cause light-headedness initially — sit or lie down
- Not recommended during high-intensity exercise