Heart coherence breathing: is there any danger in practising it?

Heart coherence breathing and danger: the two often come up together in searches, and I understand why. You were shown a simple exercise, five minutes of breathing, and then one day your head started to spin, or your heart felt strange. Or perhaps you read a negative review and now you wonder whether you should carry on.

I am a sophrologist, hypnotherapist and wellbeing coach in Bordeaux. Slow breathing is part of almost all my sessions, and it was one of the first things I learnt while getting back on my feet after a burnout. I value this tool, which is exactly why I would rather tell you what we know, what we do not know, and what breathing will not sort out.

If you are looking for the exercise itself, I explain it step by step in my article on heart coherence breathing and the 365 method.

Is heart coherence breathing dangerous?

For someone with no particular health problem, breathing at the intended pace, nothing I have read presents it as dangerous. A meta-analysis of 223 studies, led by the German Sport University Cologne, describes a simple technique with few adverse effects expected.

Still, that "few" deserves a closer look. Another meta-analysis, from the University of Sussex, pooled 12 trials and 785 adults for stress. It found no adverse events or lasting bad effects directly attributed to breathwork, but only four studies actively looked at the question, six if you count the other outcomes. So the lack of reports does not prove much by itself.

I have not found an official list of contraindications either. If you come across one, check where it comes from. I would rather tell you that than make up a list that sounds serious.

Slow breathing and fast breathing are not the same

Part of the suspicion comes from here. A review from the University of Duisburg-Essen on pranayama, covering 6 trials and 517 people being followed for mental health difficulties, notes that adverse events are more often linked to fast techniques than to slow ones, while finding this data too poorly reported to draw firm conclusions.

Heart coherence breathing means about six breaths a minute, without forcing. If your exercise involves breathing very fast, very hard or holding your breath for a long time, you are doing something else, and what I say here does not apply to it.

The real risk, as I see it: stopping there

Inserm, the French national institute for health and medical research, says plainly that the data are still patchy and that some benefits are overstated. It speaks of opening the door to abuse when people claim to sort out depression or addiction through breathing, with no other support.

For me, that is the main danger: telling yourself "I do my breathing" and putting off seeing a doctor when something is wrong. This exercise does not replace medical advice. It helps bring tension down, and that is already a lot.

Why your head can spin: breathing too hard

This is the question I hear most, and the explanation is fairly simple. When you deliberately control your breath without being used to it, you often take in too much air. You then breathe out more carbon dioxide than your body produces.

A team at the University of Warsaw measured this in 83 participants: at six breaths a minute, untrained people can slide into moderate hyperventilation. In that study, it was not enough to raise how agitated they felt. But when it is stronger, this team's work explains, the drop in carbon dioxide can bring dizziness, tingling, headaches or tension in the hands.

One instruction changes a lot

The same researcher tested a very simple instruction on 46 young adults during ten minutes of breathing: avoid breathing too deeply, keep your breath light and natural. Without the instruction, exhaled carbon dioxide dropped by 5.21 mmHg. With it, by 2.7 mmHg, and the unpleasant sensations were milder.

That is what I keep repeating in sessions: we slow the breath down, we do not inflate it. Many people think they are doing well by filling their lungs to the maximum. That is often the very thing that makes their head spin.

You can learn it

Another study by the same author, with 16 people practising ten minutes a day for a week, points the same way. On the first day, exhaled carbon dioxide fell below 30 mmHg in 37.5% of participants. By the seventh, in no one, apart from one participant who was already there before starting. The exercise also became more pleasant and more relaxing.

The mild sensations did not go away for all that. And this is a very small group. But it does explain why the first attempts are sometimes the least comfortable.

If heart coherence breathing makes you feel worse

This happens more than people admit, and it is not a failure. Listening to your breath, feeling your heart beat, counting: for someone who already watches those sensations with worry, it is a bit like staring straight at the thing that scares you.

An older paper by the researcher R. Ley offers a theoretical explanation for panic attacks during relaxation. In someone who hyperventilates all the time, sitting down to relax lowers the carbon dioxide the body produces, while the volume of air breathed stays the same. The level in the blood falls further, and sensations of panic can rise. It is a hypothesis, not an established truth, but I find it helps people stop thinking they are "bad at relaxing".

The MSD Manual points out that a panic attack can bring chest pain, a sensation of choking or dizziness. It is not dangerous in itself, but doctors first make sure no physical disorder is the cause. Do not make that call on your own. If these episodes keep coming back, talk to someone, even if slow breathing helps you.

When you are told you hyperventilate

Hyperventilation syndrome is estimated to affect about 9.5% of adults, according to the Cochrane review on breathing exercises in this situation. It included only one small trial and concluded there is no credible evidence of their effectiveness for these difficulties. That does not mean they do harm. It means we do not know, and that follow-up belongs with your doctor or whoever they refer you to.

Heart, breathing or blood pressure problem: ask your doctor

Let me be precise about what we know. The Warsaw study on the instruction was carried out on people aged 19 to 26, with no self-reported respiratory, psychiatric, neurological or chronic disease. So these results say nothing about someone living with heart failure or asthma.

There is some reassuring work, though. A study from Kraków followed 40 people being treated for chronic heart failure, with 15 minutes of breathing at six breaths a minute, twice a day, for 10 to 12 weeks. The share of people with a drop in blood pressure on standing did not move: 10% before, 10% after. But this was a small open trial, with a guiding device and medical follow-up, and the authors ask for confirmation in a larger group.

Before you start, I would therefore suggest talking to the person who follows you if:

• you have a heart condition, an irregular heart rhythm or a pacemaker;
• you take medication for blood pressure, or your blood pressure is already low;
• you have asthma, COPD or another breathing problem;
• you have fainted before;
• you are pregnant and the breathlessness is new to you.

This list comes from my own caution, not from official guidance. In these cases, the question fits in one sentence: "I would like to do five minutes of slow breathing, three times a day, is there any reason not to?" And never change your medication because you are breathing better.

How to practise without putting yourself in difficulty

Here is the version I show people who have already felt light-headed.

The exercise in five steps

1. Sit down with your feet flat and your back straight but not stiff. Not standing, and not at the wheel.
2. Breathe normally for a minute, without changing anything.
3. Slow down: three or four seconds in, the same out, with the amount of air of an ordinary breath. Your chest should hardly rise any more than usual.
4. Carry on for two or three minutes, then gradually lengthen, over several days, towards five seconds and five minutes.
5. Stay seated for a minute before getting up.

Six breaths a minute remains a guide. If you stop at eight, that is absolutely fine.

If an unpleasant sensation comes up

• Light-headedness or tingling: go back to your normal breathing and wait for it to pass. Try again later with less air.
• An urgent need to catch your breath: the pace is too slow for you. Shorten it.
• A surge of panic: open your eyes, rest your gaze on an object, feel your feet on the floor. Nothing obliges you to finish the five minutes.

If these sensations come back every time despite these adjustments, stop and talk to your doctor. And if the exercise does not suit you, there are other ways to bring tension down. I describe several in my articles on the vagus nerve and on managing stress and emotions.

The signs that breathing will not sort out

Here I am categorical: you do not breathe your way over these signs. The MSD Manual on palpitations says to go to an emergency department right away when palpitations come with any of the following:

• light-headedness or fainting;
• chest pain or pressure;
• shortness of breath;
• a pulse over 120 or under 45 beats a minute;
• known heart disease, or a family history of sudden death;
• onset during exercise.

The manual also says to go to the emergency department if palpitations do not stop, and to call emergency services in case of fainting, chest pain or shortness of breath. In France, that means calling 15 or 112. For occasional palpitations with none of these signs, a call to your doctor is enough for them to decide how soon to see you. And even without palpitations, severe chest pain or great difficulty breathing should not wait.

If you have fainted, even once, during the exercise or not, see a doctor promptly. And if exhaustion is what led you to heart coherence breathing, if you have been drained for weeks, read the signs of burnout and make an appointment with your doctor. Do not wait until your body forces you to stop.

What I do in sessions

I often start by watching how you breathe when I ask nothing of you, because your usual breathing explains a good part of the difficulties. Then we look for your rhythm, rather than applying the same one to everybody. If you have medical follow-up, we work within that: sophrology does not replace medical advice, it sits alongside it.

If counting stresses you, we go another way: dropping the shoulders, the sensations in your feet, an out-breath that lengthens by itself. You can understand what is going on in the body with my article on the parasympathetic nervous system, and see where I come from on the about page.

To begin, try the short version tonight: three minutes, sitting down, with an ordinary breath. If you would rather be guided, I see people as a sophrologist in Bordeaux, on rue Ducau, or through online sophrology. The simplest way is to book a sophrology session for adults.