What coherent breathing is
Coherent breathing means slow breathing at about five to six breaths a minute, with the inhale and the exhale the same length. At 5.5 breaths a minute, one breath takes 10.9 seconds: about 4.4 seconds in and 6.5 seconds out on the resonance pages, or 5.45 seconds each way in the equal pattern used here. Normal resting breathing for adults is about 12 to 20 breaths a minute, so this is roughly half your usual pace [Russo, Santarelli & O'Rourke 2017].
The term was popularised by Richard Brown and Patricia Gerbarg in The Healing Power of the Breath (2012). It is related to the heart coherence pattern described by the HeartMath Institute. Both use a fixed rate near the population average, not a rate tested on you.
That is the main difference from the resonance test on this site. Resonance frequency breathing uses your personal rate, usually between 4.5 and 6.5 breaths a minute, where your heart-rate swings are largest [Lehrer & Gevirtz 2014; Vaschillo, Vaschillo & Lehrer 2006]. Coherent breathing skips the test and uses 5.5. It is a reasonable starting point, but it may not be your best rate.
What the research supports
Slow breathing has been studied more than most people expect. A 2018 systematic review of 15 studies in healthy people found slow breathing under 10 breaths a minute was associated with increased HRV and respiratory sinus arrhythmia, EEG changes (more alpha, less theta), and reports of increased comfort, relaxation, pleasantness, vigor and alertness, plus reduced arousal, anxiety, depression, anger and confusion [Zaccaro et al. 2018]. The review covers healthy subjects and the studies are small.
A 2020 meta-analysis of 58 randomized controlled studies of HRV biofeedback found a small to moderate effect in its favour. The largest effects were for anxiety, depression, anger and athletic or artistic performance. The smallest were for PTSD, sleep and quality of life, each based on a small number of studies. The authors describe it as useful as a complementary approach and say further research is needed for particular uses [Lehrer et al. 2020].
A 2017 study at Brigham Young University compared three groups for 15 minutes: breathing at the individual resonance frequency, breathing one breath a minute faster, and sitting quietly. The resonance group reported higher positive mood than the other two, showed a higher LF/HF HRV ratio than the control group, and had lower systolic blood pressure during a stressful mental task afterwards [Steffen et al. 2017].
A 2017 review explains the physiology. At around six breaths a minute, breathing and the blood-pressure rhythm of the baroreflex line up, which is why heart-rate swings grow [Russo, Santarelli & O'Rourke 2017]. Normal ranges and metrics for HRV are described in Shaffer & Ginsberg 2017. These are associations from small or moderate studies, not proof. Individual results vary.
How to practise at 5.5 breaths a minute
Set the pacer to 5.5 breaths a minute with equal in and out. Breathe through your nose where possible. Keep the breath light and unforced, because over-breathing causes light-headedness. Sit or lie comfortably, and stop if you feel dizzy.
Twenty minutes a day is the practice dose in Leah Lagos's book Heart Breath Mind (2020) and in most HRV biofeedback studies [Lehrer et al. 2020]. Her ten-week program uses twice a day for about twenty minutes, with the exhale longer than the inhale. The equal pattern here is a simpler version of the same idea.
If you want to find your personal rate instead, the resonance test walks you through 6.5, 6, 5.5, 5 and 4.5 breaths a minute for about two minutes each [Lehrer, Vaschillo & Vaschillo 2000]. Without a sensor you rate each rate by comfort, which is a starting point rather than a measurement. With a chest strap and an HRV app you can enter the app's reading for each rate and the highest wins. The chest strap page explains the setup.
Worked example: one breath at 5.5
At 5.5 breaths a minute, one full breath takes 10.9 seconds. Split equally, that is about 5.45 seconds in and 5.45 seconds out. Over twenty minutes you complete 110 breaths. If you used the 40:60 resonance ratio instead, the same 10.9 seconds would be 4.4 seconds in and 6.5 seconds out. The table below shows the rates this site uses.
| Rate (breaths/min) | Seconds per breath | Inhale (s) | Exhale (s) |
|---|---|---|---|
| 4.5 | 13.3 | 5.3 | 8.0 |
| 5 | 12.0 | 4.8 | 7.2 |
| 5.5 | 10.9 | 4.4 | 6.5 |
| 6 | 10.0 | 4.0 | 6.0 |
| 6.5 | 9.2 | 3.7 | 5.5 |
| 7 | 8.6 | 3.4 | 5.1 |
| 7.5 | 8.0 | 3.2 | 4.8 |
The inhale-to-exhale ratio is 40:60 on the resonance pages, as Lehrer's manual and Lagos's book prescribe. The coherent pattern is 50:50. Both are slow breathing, and the slow-breathing evidence above applies to either.
Other patterns on this site include box breathing, 4-7-8 breathing and the physiological sigh. The books page lists the sources behind this page.
This site is educational and not medical advice. Anyone who is pregnant, has a heart or lung condition, a history of fainting, panic disorder, or epilepsy, or is being treated for a mental health condition should check with a clinician first. Slow breathing can lower blood pressure and heart rate; people on medication for either should ask their clinician. Nothing on this site is medical advice, a diagnosis or a treatment.