Glossary termPhysiology

RSA (Respiratory Sinus Arrhythmia)

The normal variation in heart rate across the breath cycle — faster on inhale, slower on exhale.

Also known as: Respiratory sinus arrhythmia

RSA is a large component of HRV. It emerges from vagal modulation of the sinoatrial node. Slow paced breathing at the resonance frequency maximises RSA amplitude and is the primary driver of high HRV readings during a breathwork session.

See also