Resonance Breathing

Resonance breathing is slow, paced breathing at about six breaths a minute, the pace at which heart rate and breath fall into step. It reliably produces a large rise in heart rate variability while you do it and may nudge your resting level up a little with regular practice, though that evidence is weak; done with a live heart-rate display (biofeedback), it has moderate evidence for easing stress and anxiety.

If you want to try it, breathe in for about 5 seconds and out for about 5. A pacing app or timer is enough to start; treat any change in your resting HRV as a small bonus, not the goal.

What it is

Heart rate variability (HRV) is the beat-to-beat shifting of the gaps between heartbeats; its fast component reflects the vagus nerve, the body's "rest and digest" brake on the heart (background on the heart rate variability page). Your heart naturally speeds up a little as you breathe in and slows as you breathe out. Breathing at about 6 breaths a minute — roughly 5 seconds in, 5 seconds out — makes that swing as large as it gets.

That pace lines the heartbeat up with the breath and works the blood-pressure reflex, the baroreflex, which senses pressure in the arteries and adjusts heart rate to keep blood pressure steady. Strengthening that reflex is the leading explanation for why the practice seems to help.^[1]

HRV biofeedback is the same slow breathing guided by a real-time display of your heart rhythm, from an app, a sensor or a clinic device, so you can see the swing and find the pace that maximises it.

What it does to your HRV

During the practice itself, slow breathing produces large rises in vagal HRV. Kept up over multiple sessions, it also nudges your resting RMSSD (the measure most apps report) upward, but the lasting effect is small and most of the underlying studies carry a high risk of bias.^[2]

Biofeedback moves the number modestly. A 2026 pooled analysis of app- or device-guided biofeedback at home found a medium rise in HRV compared with control across 10 studies.^[3] In people with heart disease, biofeedback raised overall HRV (SDNN, a measure of total variability) but not its vagal part, and most of the trials had some concerns or a high risk of bias.^[4] In heart patients, then, expect a small rise in overall HRV; a lasting vagal change is not established.

Stress and anxiety: moderate evidence

HRV biofeedback has moderate evidence for reducing self-reported stress and anxiety, with a large pooled effect in a meta-analysis whose authors still called for better-controlled studies.^[5] The picture is not uniform: in the 2026 analysis of biofeedback done at home, the effect on stress was not significant.^[6]

How slow breathing fits alongside exercise, sleep, mindfulness and relationships as a way of handling chronic stress, and whether a device adds anything over a plain breathing pace, is covered on Stress.

Not the same as meditation

Meditation hasn't been shown to do the same. Across 19 randomised trials, mindfulness meditation was not significantly better than control for resting vagal HRV; the results varied widely and the authors judged the evidence insufficient.^[7] If raising HRV is your goal, breathe slowly rather than sit still.

What hasn't been shown

No trial has shown that raising your HRV this way, or any other way, prevents heart attacks or lengthens life. Low HRV is a warning sign of poorer health, not a proven cause, so the rise you see during a session is a sign the technique is doing what it says, not a health outcome in itself.

What to do

Breathe at about 6 breaths a minute: roughly 5 seconds in, 5 seconds out.
Use a pacer. A timer or breathing app works; a live HRV display can help you find your best pace. If you have an irregular heart rhythm such as atrial fibrillation, or take beta-blockers, antidepressants or other heart medicines, the HRV display can mislead, since these distort the reading; use a plain breathing pace.
Practise regularly if you want a resting effect; the during-session rise is large, the lasting change small.
Judge it on how you feel. Stress and anxiety are where the evidence is; a higher morning HRV number is a modest side effect at best.