Does a daily slow breathing practice actually raise your resting HRV?

Twenty minutes of slow breathing a day for four weeks made people less stressed, anxious and depressed, and did nothing measurable to their resting HRV. That is the result of a randomized trial published in Scientific Reports in May 2026. Researchers split 80 adults into three groups: breathing at a personally tested resonance frequency, breathing at a fixed six breaths per minute, or a waitlist (see [1]). Both breathing groups beat the controls on stress, anxiety and depression scores. But at the final ECG check, RMSSD and high-frequency power had drifted down in all three groups, trained or not, with no difference between them. The personalized resonance frequency also failed to beat plain six-per-minute breathing.

The confusion comes from treating two separate effects as one. HRV climbs during a slow breathing session, and that part is solid. A 2022 meta-analysis of 223 studies by Laborde and colleagues found vagally mediated HRV rose during sessions, right after a single session, and after multi-session programs (see [2]). The trial authors read that last category more cautiously, describing the resting effect as small and limited to RMSSD, with other reviews similarly inconclusive (see [1]). So the rise you see on your app mid-session is real. The claim that breathwork permanently resets your baseline is the weak link.

If you want to test it on yourself, run it like an experiment. Collect two weeks of morning HRV first and judge on a rolling weekly average, because a single reading is mostly noise. Then do the breathing block at a fixed time well away from your measurement window, so you are not recording the session's afterglow and calling it adaptation. Rate your stress daily too, since that is where the trial actually found an effect. If you want a refresher on what RMSSD is capturing, our guide to what HRV is covers it. Keep the trial's own limits in mind: a waitlist rather than an active control, no tracking of home practice, and no follow-up (see [1]). Four weeks may simply be too short to move a resting number.

This is general information, not medical advice. Talk to a qualified clinician about your own situation.