Science & physiology
Why longer exhales may feel calming
Making the exhale longer than the inhale tends to feel calming because the heart slows during exhalation, and a longer exhale increases activity in the parasympathetic "rest" branch of the nervous system. This is why extended-exhale breathing is one of the most reliable calming techniques.
It is the single most useful thing to know about calming breaths: favor the out-breath.
The mechanism
Heart rate naturally dips during the exhale as vagal (parasympathetic) activity briefly rises. Spending more of each breath in the exhale phase means more time in that calmer state, which is associated with a slower heart rate and a settled feeling. [1]
What is well supported
What remains uncertain
- The ideal exhale-to-inhale ratio for a given person.
- How much of the calming feeling is physiological versus the attention and pause involved.
Practical implications
A ratio around 1 to 1.5 (for example 4 in, 6 out) is a good, comfortable target. Let the exhale be relaxed rather than forced.
Common misconceptions
- "The longer the exhale, the better." Very long, forced exhales can feel strained and are not more calming.
- "You must empty your lungs completely." A soft, comfortable exhale is enough.
Sources
- The physiological effects of slow breathing in the healthy human — Russo MA, Santarelli DM, O'Rourke D, Breathe (European Respiratory Society) (2017). doi:10.1183/20734735.009817
- How Breath-Control Can Change Your Life: A Systematic Review of Psycho-Physiological Correlates of Slow Breathing — Zaccaro A, et al., Frontiers in Human Neuroscience (2018). doi:10.3389/fnhum.2018.00353
- Effects of voluntary slow breathing on heart rate and heart rate variability: A systematic review and a meta-analysis — Laborde S, et al., Neuroscience & Biobehavioral Reviews (2022). doi:10.1016/j.neubiorev.2022.104711
This is general wellbeing information compiled by our editorial team, not medical advice.