What resonance frequency breathing is
Resonance frequency breathing means breathing slowly at your own personal rate. At that rate, the swings in your heart rate that follow each breath become as large as they can. Heart rate variability (HRV, the beat-to-beat changes in heart rate) is highest there [Lehrer & Gevirtz 2014; Vaschillo, Vaschillo & Lehrer 2006].
For most adults the rate falls between 4.5 and 6.5 breaths a minute. Normal resting breathing is about 12 to 20 breaths a minute [Russo, Santarelli & O'Rourke 2017]. The exact rate differs from person to person. In data on 56 adults, the rate was lower in taller people and lower in men than in women, with no link to age or weight [Vaschillo et al. 2006].
At around six breaths a minute, breathing and the blood-pressure rhythm of the baroreflex line up. That lining up is why heart-rate swings grow [Russo, Santarelli & O'Rourke 2017].
Where the test comes from
The standard test comes from Lehrer, Vaschillo and Vaschillo (2000). You breathe at each of 6.5, 6, 5.5, 5 and 4.5 breaths a minute for about two minutes. An HRV sensor records your heart-rate swings at each rate. The rate with the largest swings is your resonance frequency [Lehrer, Vaschillo & Vaschillo 2000].
Leah Lagos's book Heart Breath Mind (2020) describes the same test for the general reader. It then gives a ten-week program of practice at the chosen rate, usually twice a day for about twenty minutes, with the exhale longer than the inhale. This site's test follows the same rates and timing.
On this page you breathe five rates, two minutes each. After each rate you rest and give a rating. If you have a chest strap and an HRV app, you can enter the app's reading for each rate. The highest reading wins. Without a sensor, you rate each rate by comfort. That is a starting point, not a measurement.
How to read your result
If you used a chest strap, your result is the rate with the highest HRV figure. If you rated by feel, your result is the rate that felt steadiest and most comfortable. Both are useful. A felt-sense result tells you where to start. A measured result tells you where your heart-rate swings were largest on that day.
Repeat the test on another day. Your rate can shift with stress, sleep and posture. Two tests on two days give you a better picture than one. The test is a pacer with a protocol, not a medical device.
Once you have a rate, you can practise with the breathing pacer. The pacer shows the inhale and exhale timing for each rate. For the resonance pattern, the inhale-to-exhale ratio is 40:60, as Lehrer's manual and Lagos's book prescribe. The coherent pattern uses a 50:50 ratio.
Worked example
Suppose you test at 6.5 breaths a minute. That is 9.2 seconds a breath: inhale 3.7 seconds, exhale 5.5 seconds. At 6 breaths a minute, it is 10 seconds a breath: inhale 4 seconds, exhale 6 seconds. At 5.5, it is 10.9 seconds: inhale 4.4, exhale 6.5. At 5, it is 12 seconds: inhale 4.8, exhale 7.2. At 4.5, it is 13.3 seconds: inhale 5.3, exhale 8. If your highest HRV reading came at 5.5, that is your rate for now.
What the research supports
A 2020 meta-analysis of 58 randomized controlled studies looked at HRV biofeedback, which is training at the resonance frequency with feedback. It 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 call it useful as a complementary approach and say more 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. It also showed a higher LF/HF HRV ratio than the control group and lower systolic blood pressure during a stressful mental task afterwards [Steffen et al. 2017].
A 2018 systematic review of 15 studies in healthy people found slow breathing (under 10 breaths a minute) associated with increased HRV and respiratory sinus arrhythmia, EEG changes (more alpha, less theta), and reports of increased comfort, relaxation, pleasantness, vigor and alertness. It also found reduced arousal, anxiety, depression, anger and confusion. The review is of healthy subjects and the studies are small [Zaccaro et al. 2018].
These are associations from small or moderate studies, not proof. Individual results vary. Normal ranges and metrics for HRV are described in Shaffer & Ginsberg 2017.
Other slow patterns
Coherent breathing is slow breathing at about five to six breaths a minute with equal inhale and exhale. Richard Brown and Patricia Gerbarg popularised the term in The Healing Power of the Breath (2012). It is related to the heart coherence pattern described by the HeartMath Institute. It uses a fixed rate near the population average rather than a personally tested one. The slow-breathing evidence above applies.
Box breathing is inhale 4 seconds, hold 4, exhale 4, hold 4. That is 3.75 breaths a minute. It is widely taught in military and first-responder stress training. Mark Divine, a former Navy SEAL, popularised it. Trials of box breathing specifically are few. It is a slow-breathing practice with holds, so the slow-breathing evidence applies in general. In the 2023 Stanford study, box breathing was one of the arms; cyclic sighing showed the larger mood improvement [Balban et al. 2023]. Holds can feel uncomfortable. Shorter holds of 2 or 3 seconds are a reasonable way to start.
4-7-8 breathing is inhale 4 seconds, hold 7, exhale 8. That is about 3.2 breaths a minute. Dr. Andrew Weil popularised it as a relaxation and sleep exercise. He suggests four cycles at a time to begin. Evidence specific to 4-7-8 is thin. The pattern is slow breathing with a long exhale and a hold, so the general slow-breathing evidence applies. The 7-second hold is hard at first. Build up over days.
Physiological sigh, or cyclic sighing, is a full inhale through the nose, a short second inhale to top up the lungs, then a long exhale through the mouth. In a remote randomized controlled study over one month, five minutes a day of breathwork, and cyclic sighing in particular, produced greater improvement in mood and a greater reduction in breathing rate than an equal period of mindfulness meditation. The other breathing arms were box breathing and cyclic hyperventilation with retention. The authors (Balban, Huberman, Spiegel and colleagues at Stanford) call daily cyclic sighing promising as a stress-management exercise [Balban et al. 2023]. It is one study, run remotely with self-reported mood. The senior author later became an advisor to a wearables company, which the paper discloses. Andrew Huberman's podcast made the technique widely known.
Practice guidance and limits
Breathe through the nose where possible. Keep the breath light and unforced; over-breathing causes light-headedness. Sit or lie comfortably. Stop if you feel dizzy. Two minutes per rate is enough for the test. Twenty minutes a day is the practice dose in Lagos's program and in most HRV biofeedback studies [Lehrer et al. 2020].
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.
For a chest strap, a Bluetooth model such as the Polar H10 with an HRV app such as Elite HRV, HRV4Biofeedback or Kubios records beat-to-beat intervals. The app shows an HRV figure (RMSSD or the amplitude of heart-rate swings) for each rate. That is the number to enter. Wrist wearables (watches and rings) measure HRV overnight and are not suited to a two-minute paced test. The site sells no device and has no affiliate relationship with device makers. Books only, disclosed on /books/. See /hrv-chest-strap/ for more on sensors and /how-it-works/ for the full references.