Cardiac Coherence 3-6-5: The Complete Protocol

Cardiac coherence is one of the very few wellbeing practices whose instructions fit into three numbers. No posture to learn, no vocabulary, no mandatory subscription: three times a day, six breaths a minute, five minutes.

That is the 3-6-5 protocol, popularised in France by Dr David O’Hare from the HeartMath Institute’s work on heart rate variability. It is free, it works anywhere, and it is measurable — which sets it apart from most breathing exercises.

Here is the exact protocol, what it produces, and what it does not.

What 3-6-5 means, number by number

3 — three sessions a day. Not a preference: the physiological effect of a session fades in about four hours. A single session is pleasant and has no bearing on your day. Three sessions cover your waking hours.

6 — six breaths per minute. This is the core. Six cycles a minute means ten seconds per cycle: five seconds in, five seconds out. That frequency was not chosen because it is easy to remember. It matches the zone where oscillations in heart rate come into phase with the breathing rhythm — the phenomenon called coherence.

5 — five minutes. The time the system needs to settle. Below three minutes you get only the beginning of an effect; beyond six or seven, the additional benefit is small for a distinctly higher attention cost.

What actually happens in the body

Your heart does not beat at regular intervals. The gap between beats varies constantly — that is heart rate variability, and it is a sign of good adaptability, not a defect.

Part of that variability is driven by breathing: heart rate rises slightly on the inhale and falls on the exhale. This is respiratory sinus arrhythmia, and it is normal in everyone.

When you breathe at six cycles a minute, those two oscillations synchronise. The heart-rate curve, usually irregular, takes on a regular wave shape. That state is what we call cardiac coherence, and it is what a sensor shows when it displays a clean sine wave.

What the literature associates with the practice, stated carefully: a drop in perceived stress, a measurable improvement in heart rate variability, and an effect on reported sleep quality. What remains debated: the size of long-term effects, how much of it is attentional, and how well laboratory results transfer to daily use.

What it is not: a treatment. Cardiac coherence does not treat hypertension, clinical anxiety or established insomnia. If you take cardiac medication or live with an anxiety disorder, the practice is compatible with medical care — it does not replace it, and that sentence is meant literally.

The protocol, minute by minute

The five steps above amount to one gesture: sit, breathe five seconds in and five seconds out, thirty times. Everything else is comfort detail. Three points that change the experience:

Do not try to breathe deeply. This is mistake number one. The protocol asks for a rhythm, not a volume. A full deep breath over five seconds produces light-headedness and the impression that “it isn’t working”. Breathe normally, just slower.

Do not lie down. Sitting, feet on the floor. Lying changes the mechanics and makes the rhythm harder to hold. Standing works too — on a train, in a queue.

Count, or be guided. Both work. Counting takes some attention, which helps some people stay out of their thoughts and irritates others. An audio or visual guide removes the counting and leaves attention free.

The three times of day that matter

Session	Window	What it targets
Morning	Within an hour of waking, before the phone	Cushioning the waking cortisol peak and starting the day out of reaction
Midday	Before lunch, or right after a difficult meeting	Interrupting accumulation before it becomes the whole day
Late afternoon	Between 4 and 6 pm, before the evening switch	Stopping the day’s tension arriving intact into the evening

The late-evening slot is the only debatable one: practised right before bed, cardiac coherence is mildly activating for some people. If that is you, keep the third session in the late afternoon and save a long-exhale pattern for bedtime, inside a dedicated evening ritual for better sleep.

Three variants, and when to prefer them

The 5/5 is the reference rhythm, but not the only one.

Rhythm	Cycle	When to choose it
5 / 5	5 s in, 5 s out	The standard protocol, the one that establishes coherence
4 / 6	4 s in, 6 s out	When you are agitated: the longer exhale sharpens the calming effect
6 / 4	6 s in, 4 s out	In the morning, when you need to get moving

All three stay at six cycles a minute — the frequency is what counts; the split inside the cycle simply shifts the tone of the effect.

Why people quit around day nine

The protocol is trivial. Its difficulty lies elsewhere, and it is entirely logistical.

Three sessions a day means three appointments to remember, in different contexts, two of which fall inside a working day. The morning session holds effortlessly because it attaches to waking up. The late-afternoon one roughly holds. The midday one is the first to go, and it takes the others with it.

The two corrections that work:

• Attach each session to a habit that already exists, not to a clock time. “After I put my bag down” holds better than “at 12:30”.
• Accept two out of three. Two daily sessions held for six months are worth infinitely more than three held for nine days. The protocol is a target, not an exam.

Where evolum fits

evolum builds cardiac coherence into the daily ritual as one component rather than a separate module: the breathing guide arrives in the sequence, before the meditation, at the time you chose. The breathing circle sets the rhythm visually, which removes the counting — and on days when the emotional check-in reports agitation, the sequence switches to a long-exhale pattern instead of the standard 5/5.

It is also worth saying what this does not justify. You do not need any app to do 3-6-5. A clock with a second hand is enough, and a free timer does the job. If your only goal is cardiac coherence, take a free guide and keep your money: that is the honest recommendation. evolum only matters if you want a complete ritual — breathing, meditation, affirmation, guidance — composed for you instead of picked from a catalogue. That is the subject of the guided meditation guide for beginners.

FAQ

How many times a day should you practise cardiac coherence?

Three times a day is the reference protocol, because the physiological effect of a session fades after roughly four hours. Three five-minute sessions therefore cover your waking hours. Two daily sessions sustained over months remain far preferable to three abandoned after a fortnight.

What is the correct breathing rhythm for cardiac coherence?

The reference rhythm is six breaths per minute, meaning a ten-second cycle: five seconds inhaling and five seconds exhaling. That frequency matches the zone where heart-rate oscillations synchronise with breathing. The aim is not to breathe deeply but to breathe slowly and regularly.

Do you need a device or an app to practise?

No equipment is required: a clock with a second hand or simple mental counting is enough to hold the five-in, five-out rhythm. Heart rate variability sensors let you see the coherence, which is motivating at the start, but they have no bearing on the effect of the practice itself.

How quickly do you feel the effects of cardiac coherence?

The immediate effect — lower, slower breathing and a sense of slowing down — is noticeable from the first session, usually within thirty seconds of stopping the count. Reported effects on perceived stress or sleep quality take several weeks of regular practice and vary considerably between individuals.

Can you practise cardiac coherence in the evening before bed?

You can, but it does not suit everyone: for some people the 5/5 rhythm right before bed is mildly activating. If that applies to you, keep the third session in the late afternoon and reserve a distinctly longer exhale for the evening, which sharpens the shift towards rest.

Is cardiac coherence a medical treatment?

No. Cardiac coherence is a wellbeing practice, not a treatment: it does not treat hypertension, an anxiety disorder or established insomnia. It can accompany medical care but never replaces it, and any persistent difficulty warrants seeing a health professional.

What should you do if you lose count during a session?

Losing count is normal and inconsequential: pick up at the next cycle instead of starting over. The goal of the protocol is an unbroken breathing rhythm rather than accurate counting — and the irritation of restarting costs more than the few cycles missed.