Breathwork myths: 4 popular claims, checked

Why do breathwork myths spread?

Breathwork is everywhere: apps, studios, social media. And it often comes with big, exciting promises. Your nervous system will "reset". Your vagus nerve will be "activated". It will fix, boost or cure things.

I run breathwork classes and I like this stuff. So this isn't about knocking anything. It's that the real findings are interesting enough on their own, and I'd rather you hear them in the studies' own careful words.

Here are four popular claims, what the research says about each, and a verdict. I only used papers and pages I opened and read.

What to do with a big claim

1. Ask what the study actually measured: how people felt, or a number like heart rate.
2. Notice who was studied and for how long.
3. Treat slow breathing as a simple, low-cost way to settle yourself, not a treatment.
4. Skip breath holds and fast breathing unless a doctor has said they're right for you.
5. Keep taking your medicines and seeing your doctor.

Is cyclic sighing the best breathing exercise for anxiety?

What holds up. In a 2023 Stanford trial, 108 adults, mostly university students, did one of four daily practices for 28 days, about five minutes a day: cyclic sighing (a double inhale, then a long exhale), box breathing, a fast-breathing-with-hold routine, or mindfulness meditation. Everyone's mood improved. Cyclic sighing raised positive mood more than mindfulness did, and the benefit grew with more days of practice. It also lowered resting breathing rate more than mindfulness did. Balban et al.

What goes further than the study. On anxiety, all groups improved and the difference between groups wasn't significant. So cyclic sighing didn't beat the others on anxiety here. The authors say the trial was exploratory, the groups were small, it was done remotely, and it followed people for only four weeks.

Verdict: a promising small trial for mood, with no proof that cyclic sighing is "the best" for anxiety. The full story is in cyclic sighing and anxiety.

Does breathwork raise your HRV for good?

HRV, heart rate variability, is the small natural change in time between heartbeats. Higher is often (but not always) read as a sign of a flexible, relaxed nervous system.

What holds up. A 2018 systematic review of 15 studies found that slow breathing, under 10 breaths a minute, tends to raise HRV while you're doing it. Zaccaro et al.

What goes further than the study. The same review included no randomised controlled trials and no long-term follow-up. The studies used different methods and had small samples, and the authors said long-term effects need more study. They also noted that slow breathing can itself inflate one HRV measure, which clouds the reading. In the Stanford trial above, there was no significant change in HRV or resting heart rate in any group over 28 days. Balban et al.

Verdict: slow breathing changes HRV in the moment. Whether it changes your resting HRV for good isn't shown by these studies.

Does vagus nerve breathing work?

The vagus nerve is a long nerve that runs between your brain and organs including your heart and lungs. It's involved in calming the body down.

What holds up. Gerritsen and Band, in a 2018 paper, propose that slow breathing with long exhales stimulates the vagus nerve and shifts the body toward its calming side. Gerritsen and Band

What goes further than the study. That paper is a theory. The authors themselves say the mechanisms are "proposed, not proven" and that several predictions should be tested. They add that much of the supporting evidence is correlational and that HRV, often used to stand in for vagus activity, is questioned as a measure of it. They also note that some studies report controlled breathing raising sympathetic (activating) activity, depending on the instructions. The Zaccaro review also frames its proposed mechanisms as hypotheses.

Verdict: a reasonable idea, not an established fact. "Activating your vagus nerve" says more than the science does so far.

Do breathing exercises help asthma?

What holds up. A Cochrane review (the gold standard of evidence reviews) of breathing exercises for adults with asthma covered 22 trials and 2,880 adults with mild to moderate asthma. It found breathing exercises may have positive effects on quality of life, hyperventilation symptoms and lung function. Cochrane, Santino et al. 2020

What goes further than the study. Most of those trials were yoga (14). Only one used the Buteyko method and one used Buteyko with pranayama. The review's results on asthma control were inconclusive, the certainty of the evidence ranged from moderate to very low, and the evidence covers only mild to moderate asthma. It didn't test a cure, and adverse effects weren't measured.

Verdict: breathing exercises may help some people with mild to moderate asthma feel better as an addition to usual care, but the review doesn't support "cures asthma". Don't stop prescribed asthma medicine because of a breathing programme.

The research in a nutshell

How strong is the evidence? Mixed. Modest for slow breathing and mood, early for most mechanisms, weak for anything described as a cure.

What does this mean for your own practice?

Pick the practice you'll actually do. In the Stanford trial, people practised about 5 to 6 minutes a day on average, and that was enough to see mood changes. And if a class or app names a mechanism with total confidence, a gentle "interesting, is that proven?" is a fine response.