Summary
Stanford researchers compared 5-minute daily breathing exercises over 4 weeks. Cyclic sighing (long exhale pattern) improved HRV and reduced anxiety more than box breathing or mindfulness meditation.
Methods
108 healthy adults, randomized controlled trial, 4 intervention arms, 28 days
Key Findings
- Cyclic sighing increased RMSSD by approximately 12%
- Positive mood improvements persisted even on non-practice days
- Box breathing showed smaller but still significant improvements
- Mindfulness meditation was least effective for HRV specifically
Limitations
Self-reported compliance, predominantly young healthy adults, no long-term follow-up
What This Means for You
If you're choosing one breathing technique for HRV improvement, cyclic sighing (inhale through nose, second inhale to fully expand lungs, long slow exhale through mouth) has the strongest evidence. Just 5 minutes daily is sufficient.
Source
Read the original paper in Cell Reports Medicine ↗
Added to HRV Zone: 2025-01-07