Breathwork: What Does the Science Actually Say?

In the first article in this series, I talked about something that sounds almost ridiculously simple: Change the way you breathe, and you may change how you feel.

But why?

This is where breathwork becomes much more interesting than “take a deep breath and calm down.”

Breathing interacts with your cardiovascular system, nervous system, and brain. Researchers can measure some of the changes that occur when we deliberately alter the rate and pattern of breathing.

And yes, there is real research behind breathwork. There are also plenty of claims that get ahead of that research. Let's separate the two.

Your breathing and heart are already talking to each other

Your heart does not beat like a metronome. The amount of time between individual heartbeats naturally changes slightly, and breathing contributes to those changes. Generally, heart rate increases somewhat during inhalation and decreases during exhalation.

Those beat-to-beat differences contribute to something called heart-rate variability, or HRV. HRV is one of the physiological measurements researchers use when studying breathing and autonomic activity.

Slow-paced breathing is particularly interesting because breathing at certain slower rates can increase oscillations associated with HRV and interact with the body's regulation of blood pressure.

This doesn't mean that “high HRV = relaxed” and “low HRV = stressed” in every circumstance. Human physiology is considerably more complicated than an app score.

What happens when we slow the breath?

A 2024 systematic review and meta-analysis looked at 31 studies involving 1,133 participants practicing slow-paced breathing.

The researchers found immediate cardiovascular changes. Slow-paced breathing was associated with reduced systolic blood pressure, a small reduction in heart rate, and increases in certain measures of heart-rate variability. The effect on negative emotion, including perceived stress, was more modest, and evidence for long-term cardiovascular effects was limited.

I actually love findings like that. Not because they're disappointing, but because they're more useful than saying, “Breathwork regulates your nervous system!” The physiology may change even when someone doesn't suddenly feel blissfully relaxed. Bodies are complicated.

What about stress and anxiety?

A 2023 meta-analysis of randomized controlled trials examined breathwork and mental health. For its primary stress analysis, it included 12 randomized controlled trials with a combined 785 adult participants.

Breathwork was associated with lower self-reported stress compared with control conditions, with a small-to-medium effect. Researchers also found smaller beneficial associations involving anxiety and depressive symptoms.

So—is breathwork scientifically proven to cure anxiety and depression? No. The researchers specifically warned against allowing enthusiasm for breathwork to create a mismatch between hype and evidence.

Promising evidence deserves attention. It doesn't require exaggeration.

Does the technique matter?

Probably.

“Breathwork” can mean slow breathing, fast breathing, diaphragmatic breathing, nasal breathing, extended exhalation, equal breathing, breath holds, coherent breathing, alternate-nostril breathing, and quite a few other practices. Those are substantially different respiratory behaviors.

A recent review specifically asked whether choosing a particular breathing technique matters when using breathwork for chronic stress and mental health. A 2025 narrative review proposed the A52 Breath Method, drawing from research on slow diaphragmatic nasal breathing and breath retention.

But proposing a method based on existing evidence isn't the same as proving that specific combination works. The author explicitly calls for randomized controlled trials to validate the method.

What about cortisol and the “nervous system”?

You'll frequently see breathwork described as something that “regulates your nervous system,” “activates the vagus nerve,” or “lowers cortisol.”

There are physiological reasons slow breathing may influence autonomic activity, and researchers have observed changes in HRV and other cardiovascular measures. There is also research investigating cortisol and stress physiology.

But different techniques have different effects. Studies use different populations, breathing protocols, lengths of practice, and outcome measurements. The nervous system isn't an on/off switch where we simply press the “parasympathetic” button by taking four deep breaths.

Why this matters to me as a massage therapist

I don't need breathwork to cure anything in order to find it useful.

I'm not a psychotherapist. I'm not treating someone's anxiety disorder, PTSD, depression, cardiovascular disease, or respiratory condition. But I work with human beings who sometimes arrive carrying an incredible amount of tension.

If comfortable breathing helps someone settle onto the table, stop holding their breath, soften their body, or simply bring their attention back into the room, that can be useful within the context of massage.

“Would you like to try taking a few slow breaths?” is very different from “You need to breathe this way so I can regulate your nervous system.” One is an invitation. The other is a claim.

In Part Three, we'll get practical: several common breathing techniques, how they differ, and a few simple ways to experiment with them yourself.

Sources & Further Reading

Fincham, G. W., et al. (2023). “Effect of Breathwork on Stress and Mental Health: A Meta-Analysis of Randomised-Controlled Trials.” Scientific Reports, 13, 432.

https://www.nature.com/articles/s41598-022-27247-y

Shao, R., Man, I. S. C., & Lee, T. M. C. (2024). “The Effect of Slow-Paced Breathing on Cardiovascular and Emotion Functions: A Meta-Analysis and Systematic Review.” Mindfulness, 15.

https://link.springer.com/article/10.1007/s12671-023-02294-2

Little, A. L. (2025). “The A52 Breath Method: A Narrative Review of Breathwork for Mental Health and Stress Resilience.” Stress and Health.

PubMed: https://pubmed.ncbi.nlm.nih.gov/40792649/

https://pmc.ncbi.nlm.nih.gov/articles/PMC12341363/

“Breathwork for Chronic Stress and Mental Health: Does Choosing a Specific Technique Matter?”

https://pmc.ncbi.nlm.nih.gov/articles/PMC12372116/

National Geographic (2025). “How Changing the Way You Breathe Can Improve Your Brain and Body.”

https://www.nationalgeographic.com/health/article/health-benefits-of-breathing-exercises

Yabluchanskiy, Andriy & Iabluchanskyi, Mykola. Conscious Breathing: Supporting Health Throughout Life.

https://books.google.com/books/about/Conscious_Breathing.html?id=UvnVEQAAQBAJ