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Box breathing means breathing in, holding, breathing out and holding again for equal counts, usually 4 seconds each. Early research is encouraging: in a 2026 pilot, one minute of it was followed by lower anxiety than doing nothing. But in a bigger trial it did not beat mindfulness meditation, and nobody has tested how long to practice. Because it includes breath holds, check with a doctor first if you have a heart or lung condition or are pregnant.
Box breathing includes pauses with your lungs full and empty. Keep the counts comfortable, never strain, and stop if you feel dizzy or faint. Skip the holds, or check with a doctor first, if you have a heart or lung condition, a history of fainting or seizures, or you are pregnant. More in who should not do breathwork.
Picture tracing the sides of a square: up, across, down, back. That is box breathing. In for four, hold for four, out for four, hold for four.
You will see it in stress guides, apps and workplace wellbeing emails, often with big promises about calm and focus. So what has research actually tested? I read the studies I could open. Here is the friendly version, including the places where the honest answer is "we do not know yet".
How do you do box breathing?
These steps follow the way it was taught in the studies.
- Sit or lie down comfortably. Breathe through your nose if you can.
- Breathe in for 4 seconds.
- Hold gently for 4 seconds. Keep your shoulders and face soft.
- Breathe out for 4 seconds.
- Hold gently with your lungs empty for 4 seconds.
- Repeat.
If 4 seconds feels tight, use 3. If it feels easy, use 5 or 6. The main trial adjusted the count to each person's comfort, from 3 to 10 seconds a side.
How long should you do box breathing?
There is no proven answer. Nobody has compared 1, 5 and 10 minutes. The main trial used 5 minutes once a day, and the 2026 pilot used 1 minute during a tense moment. A good place to start is a minute or two, then see how you feel. There is no evidence that longer is better.
Is box breathing backed by science?
A little, so far. Here are the two studies I could read.
The 108-person trial
In 2023, a Stanford-led team published a randomized trial in Cell Reports Medicine (Balban et al.). Adults did a 5-minute exercise every day for 28 days at home. There were four groups: cyclic sighing, box breathing (21 people), a fast-breathing method with holds, and mindfulness meditation as the comparison. Most people came from a Stanford psychology class.
In the box breathing group:
- Mood rose after sessions, but not by more than it did after mindfulness. Only cyclic sighing beat mindfulness.
- Anxiety right now fell by about 3.75 points, close to the 3.95 for mindfulness. The groups did not differ.
- Heart rate variability and sleep did not change. HRV is the small natural change in time between heartbeats.
In plain words: people who did box breathing felt better after sessions, and so did people who did mindfulness. The study was not built to show that one method is better for anxiety. The authors call it exploratory, with small groups and self-reported practice.
A 2026 pilot: one minute, in real life
In April 2026, a German team published a pilot in Anxiety, Stress, & Coping (Riedl et al.). Forty-seven university students, 43 of them female, used a phone app whenever they felt tense. The app randomly gave them one minute of box breathing, one minute of cyclic sighing, or nothing to do. Anxiety was measured again five minutes later.
- Anxiety dropped more after box breathing than after nothing, and by a similar amount after cyclic sighing. It eased slightly even with no exercise.
- After box breathing, students made fewer slips on an attention test, mostly those with higher everyday anxiety.
- Both exercises were followed by slower reaction times, which the authors did not expect.
- Students found box breathing easier and less annoying than cyclic sighing, and were more likely to keep using it.
The authors note it was a small pilot of mostly young women, so it may not apply to everyone.
What is still unknown
- Long-term effects. The longest follow-up I found was 4 weeks.
- Whether it beats other simple methods. In the main trial, it did not beat mindfulness.
- What Stanford finds next. A trial (NCT06526585) compares box breathing and cyclic sighing with hypnosis and an audiobook, 10 minutes a day for 28 days, with brain scans (ClinicalTrials.gov). It plans 80 people, is due to finish on 12 November 2026, and has no results yet.
I also found no good evidence for the popular line that box breathing "resets your nervous system". The idea that slow breathing works through the vagus nerve is described by its own authors as proposed, not proven (Gerritsen and Band, 2018).
The research in a nutshell
| Study | Who | What they found |
|---|---|---|
| Balban et al. 2023 | 108 adults (21 box breathing), mostly psychology students | Mood and anxiety improved after sessions, but no more than with mindfulness. No change in HRV or sleep. |
| Riedl et al. 2026 | 47 university students, mostly women | Anxiety lower 5 minutes after 1 minute of box breathing than after nothing. |
| Stanford NCT06526585 | 80 planned adults | No results yet. |
How strong is the evidence? Early. Two small studies point the same way for short-term feelings, but neither shows box breathing is better than other calming habits, and neither tells us the best length.
Who should skip this or check first
- The main trial left out people with heart disease, glaucoma, seizure history, pregnancy, psychosis, suicidal thoughts, bipolar disorder and substance use disorders. Whether the exercise is right for you in those situations is a question for your doctor.
- The 2026 pilot also left out people with heart, brain, hormone or lung conditions, and pregnancy.
- Fast deep breathing can cause dizziness because it lowers carbon dioxide in the blood (Cleveland Clinic). Box breathing is slow, but if you feel lightheaded, stop and breathe normally.
- Never practice breath holds in water, while driving, or standing somewhere you could fall.
- If anxiety is strong, constant or getting in the way of life, please speak to a doctor or mental health professional.
Questions people ask
Is box breathing better than other breathing exercises?
Not shown. In the main trial, box breathing did not raise mood more than mindfulness, and in the pilot it was about equal to cyclic sighing for anxiety.
Do I have to hold my breath in box breathing?
In classic box breathing, yes, briefly. If holds feel uncomfortable, you can breathe in, out, in, out in a smooth rhythm instead. That is a different exercise, so the studies above do not apply to it directly.
Does box breathing help with anxiety?
People in both studies felt less anxious after sessions. In the main trial, mindfulness did about as well. It may be a handy calming habit, but it is not a treatment for anxiety.
Does box breathing improve HRV?
In the 28-day trial, HRV did not change significantly in any group. Other studies of slow breathing have found short-term changes while people breathe slowly, which we cover in slow breathing at 6 breaths a minute.
Was box breathing invented by Navy SEALs?
You will often see it described as a military technique, and the 2026 pilot's authors mention a military background. I did not find a source I could check for who first used it, so I will not give you a story I cannot back up.
Sources and further reading (5)
- Balban MY, Neri E, Kogon MM, Weed L, Nouriani B, Jo B, Holl G, Zeitzer JM, Spiegel D, Huberman AD. Brief structured respiration practices enhance mood and reduce physiological arousal. Cell Reports Medicine, 2023. Full text. PMC9873947
- Riedl EM, Bracklo T, Wimmer K, Perzl J, Gdynia H-J, Thomas J, Surzykiewicz J. Simply breathing anxiety away? A pilot, just-in-time ecological momentary intervention study of one-minute cyclic sighing versus box breathing. Anxiety, Stress, & Coping, 2026. Full text. doi.org/10.1080/10615806.2026.2659809
- Stanford University. Examining the Immediate and Training Effects of Regular Stress Reduction Practices on Psychophysiological Markers of Anxiety (NCT06526585), ClinicalTrials.gov registry record. clinicaltrials.gov/study/NCT06526585
- Gerritsen RJS, Band GPH. Breath of Life: The Respiratory Vagal Stimulation Model of Contemplative Activity. Frontiers in Human Neuroscience, 2018. First part of the full text read. PMC6189422
- Cleveland Clinic. Hyperventilation (patient information page). my.clevelandclinic.org
Updated 24 October 2026. We re-check posts when new research comes out.
