Breathwork reduces stress

Deliberate breathing practices lower self-reported stress by a small to moderate amount in randomized trials, most of which compared them with doing nothing. When two larger trials compared a breathing technique with a sham breathing pattern, stress fell by about the same amount in both groups. A 2023 review pooled 12 randomized trials in 785 adults and found stress scores fell more with breathwork than in comparison groups (effect size 0.35), with similar small effects on anxiety (0.32, 20 trials) and low mood (0.40, 18 trials). Ten of the 12 trials used slow breathing. The effect was smaller against other activities that take the same time and attention (0.26, 5 trials) than against doing nothing (0.37, 7 trials). Most of the trials had some risk of bias, all measured stress with questionnaires, and too few followed people up after the practice ended to say whether the effect lasts.

The two larger trials were run online in the UK after that review, by its lead author, and participants were not told whether they had the technique under test or the sham. In 400 adults, four weeks of slow breathing at about 5.5 breaths a minute, around 10 minutes a day, lowered stress scores by the same amount as breathing paced at 12 breaths a minute, with still no difference a month later. In 200 healthy adults aged 18 to 39, three weeks of daily fast breathing with long breath holds lowered stress slightly more than a sham at 15 breaths a minute with short holds, a difference small enough to be chance; the two pooled trials of fast breathing had not shown a clear effect either. Stress scores fell in both groups of each trial, so these results do not show that a daily breathing session does nothing. In both, the specific pattern produced no measurable difference from paced breathing at an ordinary rate. Fast styles, including Wim Hof style breathing and holotropic breathwork, carry risks slow breathing does not: fainting, which can be fatal in or near water, and a lowered seizure threshold, since brief deliberate hyperventilation is used in clinics to bring on seizures. Reviews of these practices advise caution for people who are pregnant or who have epilepsy, heart or blood vessel disease, panic disorder or psychosis. The pooled trials were in adults, and only one was in people with a mental health condition, where the result was not clear.

In a 2023 trial run remotely from Stanford, 108 adults did five minutes a day for a month of one of three breathing patterns or of mindfulness meditation. Anxiety dropped after each session by similar amounts in all four groups. Breathing practices, especially cyclic sighing, which stretches out the exhale, raised positive mood more than meditation did and slowed resting breathing rate. The trial was registered after it had ended and measured many outcomes, and its clearest difference was in mood rather than anxiety. In the UK trial of fast breathing, participants practised lying down and away from water, and people who were pregnant or who had epilepsy, heart or blood pressure problems, a history of fainting or panic attacks were not enrolled. About 9 percent of each group reported unpleasant short-term effects and none reported lasting ones; no heart or blood pressure measurements were taken.

Slow breathing, around six breaths a minute, reliably raises heart rate variability, a marker of the part of the nervous system that slows the body down. A 2022 review of 223 studies found this during practice, immediately after a single session and after programmes of several sessions. Whether that change is what lowers stress is not established: in the 400-person trial, breathing at the slow rate lowered stress no more than breathing at 12 breaths a minute. A 2024 pooled analysis of 31 studies of slow breathing in healthy adults, nine of them randomized, found heart rate variability higher straight after practice, while the fall in negative emotion, measured by perceived stress in five of the seven studies that reported it, was not statistically clear.

US federal information on complementary health lists breathing exercises among relaxation techniques and describes them as generally safe for healthy people, with occasional reports of increased anxiety and rare reports of worsened symptoms in people with epilepsy, certain psychiatric conditions or a history of abuse or trauma. A 2013 World Health Organization guideline on conditions related to stress does not assess breathwork as a stress treatment; for people who hyperventilate in the month after a traumatic event, it describes coaching them back to normal breathing, not deeper and quicker than usual, and it recommends against paper-bag rebreathing for children.

The practices tested ranged from diaphragmatic and paced breathing to yogic pranayama, taught in person, online or both, over sessions lasting minutes to weeks.