Watching your breath eases stress a little, while forceful breathwork near water can kill

Key takeaways

• In a 2023 trial of 400 adults, a slow “coherent” breathing pace cut stress no more than a placebo pace of 12 breaths a minute; both groups improved about equally.
• A 2023 review of 12 trials with 785 adults found breathwork lowered stress by a small to medium amount, but most studies had a moderate risk of bias.
• Five minutes a day of cyclic sighing lifted mood more than mindfulness in a small, month-long Stanford trial, though anxiety fell about equally across groups.
• For panic disorder, one FDA-cleared approach trains people to breathe slower and with less volume, not deeper, to bring low carbon dioxide back up.
• The American Red Cross, USA Swimming and the YMCA warn that hyperventilating before swimming underwater, or holding your breath for long periods, can lead to unconsciousness and death.

In 2023, researchers at the University of Sussex in England ran a test that few breathing programs ever face. They asked 400 adults to breathe along with a recording for about 10 minutes a day for four weeks¹.

Half followed a slow “coherent” rhythm of about 5.5 breaths a minute. The other half breathed at 12 breaths a minute, a version the researchers built as a placebo. Neither group knew which one they had¹.

After a month, stress had dropped in both groups by about the same amount. Anxiety, low mood and well-being followed the same pattern¹. The slow pace added nothing the researchers could measure.

That doesn’t make breathing practice useless. It suggests much of the benefit may come from what both groups shared: a daily pause, attention turned toward the body and the hope of feeling calmer. That is the core of breath awareness.

Breathing runs on autopilot, yet you can take the controls at any moment. This article covers what research shows about gentle practices, popular techniques and devices, and why forceful breathing near water can be deadly.

Noticing your breath and steering it are different skills

Breath awareness means watching the breath as it is. You notice air at the nostrils, the rise of the belly and the small pause after each exhale, without trying to change anything.

Breath control means changing the breath on purpose. You might slow it, stretch the exhale, hold it or speed it up.

Both have deep roots. Early Buddhist teachings on mindfulness of breathing, called anapanasati, begin with simply knowing whether a breath is long or short. Later steps widen attention to the whole body and let bodily activity calm down¹⁵. Yoga’s pranayama practices, by contrast, shape the breath deliberately, with set counts, holds and nostril patterns.

Modern methods fall along the same range. Mindfulness classes teach awareness. Slow-paced breathing, box breathing and the Buteyko method are forms of control. At the far end sit fast, forceful styles, such as the hyperventilation exercises popularized by the Wim Hof Method¹⁴.

The difference matters for safety. Hard, fast breathing blows off carbon dioxide, which changes how your body senses the need for air¹⁴. The more forcefully you steer, the more care you need.

Pooled trials show a small benefit, but no “perfect” pace has proved itself

The same Sussex team first pooled earlier research. In a 2023 meta-analysis, a study that combines the results of many trials, they found 12 randomized controlled trials of breathwork for stress, with 785 adults in all². A randomized controlled trial assigns people by chance to a treatment or a comparison group.

Breathwork lowered stress by a small to medium amount compared with control groups². Results for anxiety, from 20 trials, and depression, from 18 trials, looked similar².

Most studies had a moderate risk of bias, meaning design flaws could have tilted the results². The team’s later placebo trial then found no edge for the slow pace¹.

A note on ties: lead author Guy Fincham, a Sussex doctoral researcher, also teaches breathwork with the Breath-Body-Mind Foundation in New York, according to a 2023 fellowship profile⁹. If anything, that makes his placebo trial’s null result more credible.

So setting aside time to breathe slowly and attentively seems to help a little, but no single count or rhythm has proved special.

A five-minute sigh lifted mood in one Stanford trial

The best-known test of cyclic sighing is a 2023 study led by Stanford University researchers, with neurobiologist Andrew Huberman as senior author³.

The technique is simple. Breathe in through the nose, then take a second, shorter sip of air on top. Then let out a long, slow exhale. Repeat for five minutes³.

The team compared it with three other five-minute daily practices for a month: box breathing (equal counts of breathing in, holding and breathing out), cyclic hyperventilation with breath retention, and mindfulness meditation³. Of 108 people enrolled, most came from a Stanford undergraduate psychology class³.

The breathing groups, and cyclic sighing above all, raised daily positive mood more than mindfulness did and lowered breathing rate more³. Sighing was the only style that beat mindfulness on mood by itself, and its edge grew the more days people practiced³.

Some details often get lost:

• Anxiety fell in every group, including mindfulness, with no difference between them³.
• Heart rate variability, resting heart rate and sleep didn’t change³.
• The study began as an exploratory project and was registered after the fact, not in advance³.
• Each group had only about 20 to 33 people, and the trial ran four weeks with no follow-up³.
• About 1 in 10 people who answered a debriefing survey reported a negative experience with the exercises³.

On disclosures: Huberman became an adviser to WHOOP, the wearable maker, in 2022, and WHOOP donated the wrist straps used in the study. The paper says the company had no role in the design or analysis³.

Evidence label: promising but early. One small, month-long trial with an active comparison group is a good start, not a verdict.

An FDA-cleared breathing device looked weaker in independent trials

In 2002, the FDA cleared RESPeRATE, a biofeedback device that leads users through guided, monitored breathing exercises⁶. Its cleared uses are relaxation and stress reduction, and an add-on treatment for high blood pressure alongside other care⁶.

In 2013, the American Heart Association called device-guided breathing “reasonable” for lowering blood pressure. That’s a Class IIa recommendation with Level B evidence, a step below the top rating it gave aerobic exercise⁴.

Later reviews were cooler. A 2016 evidence review by Mahtani and colleagues noted that the modest benefit seen in an earlier meta-analysis vanished when trials sponsored by or involving the manufacturer were set aside⁵. An independent trial and an independent pooled analysis of patient data found no overall benefit, along with signs of possible side effects⁵. The reviewers, who declared no conflicts of interest, concluded the pooled evidence doesn’t support routine use⁵.

Slow breathing without a gadget shows a similar pattern. A 2019 review described by the National Center for Complementary and Integrative Health (NCCIH) found that slow breathing exercises lowered blood pressure modestly. But the studies were short, at high risk of bias, and none tracked heart attacks or strokes⁷.

If you have high blood pressure, NCCIH advises staying with your prescribed treatment and talking with your clinician before adding a complementary approach⁷.

For panic, the goal can be breathing less, not deeper

Some people with panic disorder breathe in a way that keeps their carbon dioxide low, and one treatment aims straight at that pattern⁸.

Alicia Meuret and colleagues developed capnometry-assisted respiratory training, or CART⁸. A sensor at the nose reads the carbon dioxide in each breath out. Patients watch the readout and learn to slow their breathing until the numbers settle into a normal range⁸. For people whose levels run low, the key is taking in less air with each breath, not more⁸.

That runs against the familiar advice to take a deep breath. One 2018 paper from Meuret’s group is titled “Hypoventilation therapy alleviates panic by repeated induction of dyspnea,” the medical word for breathlessness⁸.

In a randomized trial published in 2010, CART helped people with panic disorder about as much as cognitive therapy did⁸. The FDA cleared a home version, Freespira, for panic disorder in 2013 and for PTSD in 2018⁸. It’s a 28-day program with two 17-minute sessions a day⁸.

In a 2022 analysis of real-world data from 1,395 people with panic disorder, average symptom scores fell by about half⁸. But there was no comparison group. Three of the four authors work for Freespira and hold equity in it, the fourth is a paid scientific adviser, and the company funded the study⁸.

Evidence label: promising but early. Our upcoming article on anxiety covers panic treatment in more depth.

Breathing retraining helps asthma quality of life more clearly than lung function

A 2020 Cochrane review pooled 22 studies with 2,880 adults who had mild to moderate asthma¹⁰. Most tested yoga. One tested the Buteyko method alone and another combined Buteyko with pranayama¹⁰.

Breathing exercises probably improved quality of life and symptoms of over-breathing, with moderate-certainty evidence¹⁰. They didn’t clearly change asthma-control scores, and lung-function results were mixed and uncertain¹⁰. It can’t speak to severe asthma, which wasn’t studied¹⁰.

A review published in June 2026 looked at six studies with 1,098 adults, four of them randomized trials. It found possible gains in quality of life and asthma-control scores, but no change in lung function and no drop in severe attacks¹¹. In one 60-person trial from 2024, Buteyko was linked to about 20% less use of reliever and steroid inhalers, with asthma control maintained¹¹.

Those authors report that the Global Initiative for Asthma’s 2024 report recommends breathing exercises as an add-on for adults whose symptoms persist despite the best medicine¹¹. Keep using your prescribed inhalers, and bring any breathing program to the clinician who treats your asthma¹⁰¹¹.

Evidence label: promising but early.

Wim Hof breathing changed one immune test, and in water it can turn deadly

Dutchman Wim Hof developed a training program that combines meditation, cold exposure and hyperventilation-style breathing¹²¹⁴.

In a 2014 study published in PNAS, Dutch researchers trained a small group of healthy young men in the program¹². Then the trained men and an untrained group received endotoxin, a bacterial fragment that sets off brief flu-like symptoms¹².

The trained men released more adrenaline, showed a calmer inflammatory response and reported fewer flu-like symptoms¹². It was a striking result, but the study was small, limited to healthy young men, and bundled breathing with cold and meditation, so it can’t show what breathing did alone. In a follow-up analysis, men who were more optimistic showed bigger adrenaline responses, a hint that expectations matter¹².

The clearest danger is water. Rising carbon dioxide, not falling oxygen, is what normally makes you feel the need to breathe. Hyperventilating blows off carbon dioxide and quiets that alarm, so oxygen can drop until you pass out without warning¹⁴.

Underwater, a person who blacks out may take a reflex breath and pull in water. Because there’s no struggle, onlookers may think the swimmer is just holding their breath¹⁴. Joanna Chan, an emergency physician at Singapore General Hospital writing for that country’s national sports agency, says Wim Hof-style hyperventilation done in or near water has led to deaths around the world, citing news reports¹⁴. She notes that the official Wim Hof website itself warns against using the techniques near water¹⁴.

In 2022, the American Red Cross, USA Swimming and the YMCA of the USA warned in a joint statement that hyperventilating before swimming underwater, and holding your breath for long periods, can starve the body of oxygen¹³. The result can be loss of consciousness and death, they wrote¹³. They urge instructors to limit breath holding to a single breath and lifeguards to respond fast to anyone motionless in the water¹³. They also dropped the term “shallow water blackout,” since depth isn’t what matters¹³.

For claims about nose breathing and mouth taping, see our articles on breathing during exercise and on sleep apnea.

Try it: a three-minute breath awareness practice

Breath awareness fits what many natural-health readers prize. It’s free, needs no product or app, and comes from contemplative traditions many centuries old. This script is our own, written for beginners.

Minute 1: arrive. Sit with your feet on the floor. Keep your eyes open with a soft gaze, or close them if that feels fine. Feel where your body meets the chair. Notice that you’re breathing. You don’t need to change anything.

Minute 2: Find the breath. Pick one spot to watch: the nostrils, the chest or the belly. Follow one breath in, the turn, the breath out and the pause. If it helps, silently note “long” or “short,” a nod to anapanasati’s first steps¹⁵. When your mind wanders, notice where it went and come back. That return is the practice.

Minute 3: widen. Let your attention spread to the whole body breathing: shoulders, ribs, belly, hands. If the breath slows on its own, let it. To finish, name one thing you can see and one thing you can hear, then carry on with your day.

Optional: steer gently. If you’d like to try breath control, let each exhale run a little longer than the inhale, or try cyclic sighing for one to five minutes³. If it feels like a strain or makes you more anxious, ease off and go back to simply watching³⁷.

When to get help. See a health care provider if anxiety, panic or low mood is severe or lasts a long time⁷. If someone is motionless in the water, get them out and get help right away¹³. If distress comes with thoughts of harming yourself, call or text the 988 Suicide & Crisis Lifeline. In a life-threatening emergency, call 911.

What the evidence says, rated

Practice	What studies found	Evidence level
Breathwork for stress, overall	Small to medium benefit in 12 trials; moderate risk of bias2	Promising but early
A slow “coherent” pace over an ordinary pace	No added benefit in a 400-person placebo trial1	Not enough evidence
Cyclic sighing	Beat mindfulness on mood, not anxiety, in one small trial3	Promising but early
Device-guided breathing for blood pressure	AHA rated it reasonable in 2013; independent trials found no overall benefit45	Not enough evidence
CART for panic disorder	Matched cognitive therapy in a trial; company-run data lack controls8	Promising but early
Breathing retraining for asthma	Better quality of life, no clear change in lung function1011	Promising but early
Wim Hof-style breathing for immunity	One small lab study, bundled with cold and meditation12	Not enough evidence
Hyperventilation or long breath holds in water	Can cause sudden blackout and drowning1314	Evidence says no, or unsafe

Questions readers ask

The bottom line

Gentle breathing practices, from simply watching the breath to slow, easy exhales, have modest, early evidence for easing stress. The strongest test so far suggests the daily pause and the attention matter more than any special count.

Forceful breathwork is a different matter. It can make you faint, so never do it in water, while driving or standing, and check with a clinician first if you have a heart, seizure or mental health condition. For panic, asthma and blood pressure, breathing practice works best as an add-on to proven care.

Related reading

• A body scan may ease pain’s distress more than the pain itself
• The viral “military sleep method” hasn’t been tested in trials, unlike older relaxation methods
• Your HRV is personal and noisy, so read the trend rather than the day
• Breathing takes care of itself in most workouts, but lifting, side stitches and asthma need a plan
• “FDA registered” isn’t “FDA approved”: a buyer’s map to wellness devices

Sources

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2. Fincham GW, Strauss C, Montero-Marin J, Cavanagh K. “Effect of breathwork on stress and mental health: a meta-analysis of randomised-controlled trials.” Scientific Reports, 2023;13:432 (University of Sussex repository). pubmed.ncbi.nlm.nih.gov
3. Balban MY, Neri E, Kogon MM, et al. “Brief structured respiration practices enhance mood and reduce physiological arousal.” Cell Reports Medicine, 2023;4:100895 (PMC full text). pmc.ncbi.nlm.nih.gov
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9. Sylff. “Voices” profile of Guy Fincham, University of Sussex. sylff.org, March 23, 2023. sylff.org
10. Santino TA, Chaves GSS, Freitas DA, Fregonezi GAF, Mendonça KMPP. “Breathing exercises for adults with asthma.” Cochrane Database of Systematic Reviews, 2020, Issue 3, CD001277 (PEDro record). search.pedro.org.au
11. Crespo-Lessmann A, Vélez-Segovia E, Paz L, Plaza V. “Breathing exercises as adjunct therapy in adult asthma: a systematic review.” F1000Research, 2026;15:996. f1000research.com
12. van Middendorp H, Kox M, Pickkers P, Evers AWM. “The role of outcome expectancies for a training program consisting of meditation, breathing exercises, and cold exposure on the response to endotoxin administration: a proof-of-principle study.” Clinical Rheumatology, 2016;35:1081-1085 (Leiden University repository; summarizes Kox et al., PNAS, 2014). scholarlypublications.universiteitleiden.nl
13. American Red Cross, USA Swimming and YMCA of the USA. “Joint Statement on Hypoxic Blackout.” November 2022. Hypoxic Blackout – Joint Statement – Red Cross Y USA Swimming 10-31-2022.pdf
14. Chan Shi-En J (Singapore General Hospital). “Breath-holding with hyperventilation: an invisible danger.” ActiveSG Circle, Sport Singapore.
15. Anālayo Bh. “Buddhist Antecedents to the Body Scan Meditation.” Mindfulness, 11(1):194-202, first published 2018 (University of Hamburg copy). buddhismuskunde.uni-hamburg.de