Cardiac coherence: guided exercise, method and benefits
Medical review in progress.
Lehrer and Gevirtz (Frontiers in Psychology, 2014) write that most studies find the largest amplitude of heart rate variability around 0.1 Hz, i.e. six breaths per minute. This guide makes each breath last 10 seconds, 5 to breathe in and 5 to breathe out, for 5 minutes (30 breaths). It does not measure your heart.
The calculation runs in your browser. No data is sent or stored.
Example: 5 minutes × 6 breaths = 30 breaths. Each breath lasts 60 / 6 = 10 seconds.
Do the exercise now
The guide is on this page: a circle that grows and shrinks for 5 minutes. There is no video to open elsewhere. The sound, if switched on, only marks the change between breathing in and out.
Five seconds breathing in and five seconds breathing out is the split chosen to land on six breaths per minute. The Lehrer and Gevirtz article does not prescribe this exact split. It also mentions, in later work cited by the same authors, an average close to 0.09 Hz, i.e. about 5.5 breaths per minute and a breath of about 11 seconds. The guide stays at 6 per minute, the frequency cited for most studies in that review.
The method: rhythm, duration, frequency
A 5-minute session has 30 breaths. Three sessions would be 90 breaths. The review sets no mandatory number of sessions per day for the general public. It describes heart rate variability biofeedback, with feedback of the heart rhythm, which this page does not do: here, only the breathing rhythm is guided.
Usual resting breathing, in the same article, often sits between 0.15 and 0.4 Hz, i.e. 9 to 24 breaths per minute. Six per minute is slower.
What the research says
The article explains that, around six breaths per minute, heart rate oscillations and breathing are in phase, and that the amplitude of variability is then larger. The mechanism discussed is the baroreflex: at this frequency, heart rate and blood pressure oscillate in opposite phase.
The authors write that a body of studies suggests biofeedback training can help hypertensive patients lower their pressure. This page does not repeat that as a promise. The exercise guided here is not biofeedback (it does not display your heart rhythm) and it is not aimed at anyone to treat blood pressure.
Cardiac coherence and HRV
Heart rate variability is the time gap between beats. The article links its amplitude to breathing frequency. Seeing the effect of a habit over several weeks would require repeated recording. Elio follows this variability at night as a wellbeing indicator, not as an examination.
When to practice
The guide can be started in the morning, during the day or in the evening. Nothing in the article read rules out the evening. Stop if you feel uncomfortable. In case of breathing difficulty, chest pain or faintness, stop and talk to a doctor.
Precautions
This is not a guided meditation and it is not a treatment. The difference from a meditation: here the only instruction is the rhythm, six breaths per minute, with no imposed mental object.
Do not look on this page for an effect on anxiety or blood pressure. The review article speaks of research on several disorders and on performance, and says several mechanisms remain little studied. That does not become an indication.
This exercise does not treat anxiety, blood pressure or any disease. It does not replace care.
Frequently asked questions
How many times a day should you do cardiac coherence?
The review read sets no quota for a general-public session without biofeedback. The calculation is linear: each 5-minute block has 30 breaths. Three blocks would have 90 breaths.
How long before you feel an effect?
The article indicates that the sinusoidal pattern of variability often appears within a fraction of a minute when breathing is guided at the right frequency, in people practising biofeedback with heart rhythm feedback. This page does not measure that effect in you.
Can you do it in the evening?
Yes, the guide starts at the time you choose. The text read does not restrict the exercise to a time of day.
What is the difference from meditation?
The guide offers only a rhythm: breathe in for 5 seconds, breathe out for 5 seconds, for 5 minutes. It gives no attention instruction other than this rhythm.
Does cardiac coherence lower blood pressure?
This page does not promise it. Lehrer and Gevirtz cite biofeedback studies in hypertensive or prehypertensive people. The exercise here does not measure blood pressure and does not replace a treatment.
Sources
Read also
Elio follows heart rate variability at night. Elio measures heart rate variability continuously, including at night, as a wellbeing trend. It does not prove the effect of a session. See the Elio band