Key takeaways
- A 2018 systematic review defined slow breathing techniques as fewer than 10 breaths a minute; Wikipedia gives 12 to 15 as typical for a healthy adult at rest.
- A 2018 systematic review linked slow breathing with higher heart rate variability and with reports of more relaxation and less anxiety, but included only 15 studies.
- A 2023 meta-analysis of 12 trials with 785 adults found breathwork lowered self-reported stress by a small-to-medium amount, with most studies at moderate risk of bias.
- A 2023 trial reported that breathwork, especially exhale-focused cyclic sighing, improved mood more than mindfulness meditation; it was one month-long trial and does not establish a best technique.
- The research does not show that breathing exercises treat anxiety disorders, insomnia or other conditions.
Research links slow breathing with higher heart rate variability and with people reporting more relaxation, and a 2023 meta-analysis found breathwork was associated with a small-to-medium reduction in self-reported stress; the same authors warned against letting hype run ahead of evidence. Breathwork has, in that meta-analysis's words, "recently received an unprecedented surge in public interest". This guide looks at what the research on slow breathing shows, how strong it is, and where its limits are.
How slow "slow breathing" is in research
Wikipedia gives the typical resting respiratory rate for a healthy adult as 12 to 15 breaths a minute, with the brain's respiratory centre setting a quiet rhythm of about two seconds in and three seconds out. Slow breathing in research means something much slower. A 2018 systematic review in Frontiers in Human Neuroscience defined slow breathing techniques as fewer than 10 breaths a minute.
The exercises covered on this site all fall below that line. If one count is one second:
| Exercise | One breath takes | Breaths a minute |
|---|---|---|
| Typical resting breath (2 s in, 3 s out) | 5 seconds | 12 |
| NHS exercise for stress (count 5 in, 5 out) | 10 seconds | 6 |
| Box breathing (4 in, 4 hold, 4 out, 4 hold) | 16 seconds | 3.75 |
| 4-7-8 breathing (4 in, 7 hold, 8 out) | 19 seconds | About 3.2 |
Whatever their names, these exercises share a rhythm far slower than the typical resting rate.
Findings of the 2018 review and the 2023 meta-analysis
The 2018 review searched two databases and screened 2,461 abstracts, but only 15 studies met its criteria. Across them, slow breathing was associated with increased heart rate variability and respiratory sinus arrhythmia, changes in brain activity on EEG (more alpha and less theta power), and psychological effects that participants reported: more comfort, relaxation, pleasantness, vigour and alertness, and fewer symptoms of arousal, anxiety, depression, anger and confusion. The studies were in healthy people.
A 2023 meta-analysis in Scientific Reports went further by pooling randomised controlled trials of breathwork. For self-reported stress, it combined 12 trials with 785 adults and found breathwork was associated with lower stress than control conditions, a small-to-medium effect. Results for anxiety (20 trials) and depressive symptoms (18 trials) were similar in size.
Cyclic sighing, box breathing and meditation compared
The meta-analysis compared breathwork with non-breathwork controls, not one technique with another. One study that did compare techniques is a 2023 randomised trial in Cell Reports Medicine, which compared daily five-minute sessions of cyclic sighing, box breathing and cyclic hyperventilation with retention against mindfulness meditation for a month. Breathwork, especially exhale-focused cyclic sighing, improved mood and lowered breathing rate more than meditation did. It is a single, short trial, so it hints that long exhales matter rather than proving it.
How much practice the studies used
In the studies cited here, the amount of practice was small:
- the 2023 Cell Reports Medicine trial used five minutes a day for a month;
- a 2017 trial of diaphragmatic breathing used 20 sessions over eight weeks, at about four breaths a minute;
- a 2022 study of 4-7-8 breathing measured effects straight after three sets of six cycles.
The NHS, for its part, suggests at least five minutes of its basic exercise and doing it regularly, as part of a daily routine. These abstracts do not report testing whether more practice brings more benefit, so they do not establish an ideal amount.
What the research does not support
The same meta-analysis that found benefits also judged most of its studies to be at moderate risk of bias and warned of "a miscalibration between hype and evidence". Taken together, the research has clear limits:
- Short-term, mostly healthy samples. The individual studies cited in these guides ran from a single session to eight weeks, and most recruited healthy adults.
- Self-reported outcomes. The meta-analysis's main outcome was self-reported stress, not a physical measurement.
- No proof of treatment. None of this shows that breathing exercises treat anxiety disorders, insomnia, high blood pressure or other conditions.
- No best technique. The evidence does not establish one pattern as best for everyone.
Fitting a few minutes of slow breathing into a day
The NHS describes its breathing exercise as a calming technique that takes just a few minutes, can be done anywhere, and gives the most benefit when done regularly as part of a daily routine. Choose a pattern that feels comfortable, breathe without forcing it, and stop and breathe normally if you feel dizzy. Guides on this site cover box breathing, 4-7-8 breathing and diaphragmatic breathing.
Kawaii Cute Breathe Relax Care, one of our health and nutrition apps, paces slow breathing with an animated guide and timer, from a one-minute reset to a bedtime wind-down. It is a relaxation tool, not a treatment; the app guide explains its routines.
Good to know
Frequently asked questions
How slow is slow breathing?
Is there scientific evidence that breathing exercises reduce stress?
Which breathing technique works best?
Can slow breathing treat anxiety?
Sources
- How Breath-Control Can Change Your Life: A Systematic Review on Psycho-Physiological Correlates of Slow Breathing (Zaccaro et al., Frontiers in Human Neuroscience, 2018) (opens in a new tab)PubMed — accessed
- Effect of breathwork on stress and mental health: A meta-analysis of randomised-controlled trials (Fincham et al., Scientific Reports, 2023) (opens in a new tab)PubMed — accessed
- Brief structured respiration practices enhance mood and reduce physiological arousal (Balban et al., Cell Reports Medicine, 2023) (opens in a new tab)PubMed — accessed
- The Effect of Diaphragmatic Breathing on Attention, Negative Affect and Stress in Healthy Adults (Ma et al., Frontiers in Psychology, 2017) (opens in a new tab)PubMed — accessed
- Effects of sleep deprivation and 4-7-8 breathing control on heart rate variability, blood pressure, blood glucose, and endothelial function in healthy young adults (Vierra et al., Physiological Reports, 2022) (opens in a new tab)PubMed — accessed
- Respiratory rate (opens in a new tab)Wikipedia — accessed
- Breathing exercises for stress (opens in a new tab)NHS — accessed
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