Breathe in for a count of 4, hold for 4, breathe out for 4, hold for 4, and repeat for a few minutes: that is box breathing, named for the square its four equal phases trace. In a month-long Stanford trial of daily practice, people felt calmer after each session yet did no better than the same short dose of mindfulness meditationmindfulness: Paying attention to what is happening in the present moment, including thoughts and sensations, on purpose and without judging it. The word covers both a state of mind and the courses that train it, and most research tests the courses.Full entry in the glossary.¹ A systematic reviewsystematic review: A review that fixes its question and its rules for including studies in advance, then searches out every study that fits and weighs them together. Some systematic reviews pool the results into a meta-analysis; others describe what the studies found without combining the numbers.Full entry in the glossary published in 2026 found only 8 randomized trials that tested box breathing itself; several showed short-term benefits for stress, anxiety or mood, but effects on heart rate and breathing were inconsistent and long-term data were scarce.²

The method takes five steps:

1. Sit or lie down and set a timer
2. Choose a count you can keep without straining
3. Breathe in, hold, breathe out, hold, for the same count
4. Keep going for a few minutes, then breathe normally
5. Stop if you feel dizzy, short of breath or panicky

What box breathing is, and why the holds slow you down

Box breathing, also called tactical or combat breathing, is a paced pattern in which the in-breath, a pause, the out-breath and a second pause all last the same time. A 2021 German lab study led by Stefan Röttger, read as an abstract only, notes that military and police personnel use tactical breathing to stay calm and keep performing in danger, but that evidence for it is limited.³

The pauses do the slowing. At 4 seconds a phase, you breathe fewer than 4 times a minute, well under the 10 a minute that a 2018 systematic review by Andrea Zaccaro and colleagues used to define slow breathing. Across the studies of healthy people it gathered, slower breathing went with a larger natural rise and fall of heart rate with each breath, and with feeling more relaxed and less anxious. None of those studies was a randomized controlled trial, so the review shows links, not proof.⁴

A 2022 meta-analysis of more than 200 studies, read as an abstract only, found the same signal in heart rate variability tied to the vagus nerve, a marker of the body’s calming branch: it was higher during slow breathing, right after a session and after programs of several sessions.⁵

Myth

Box breathing is a special military method that resets your nervous system.

Fact

It is one form of slow breathing. A handful of small trials show short-term calm, and none shows it is better overall than other slow patterns.

In practice, four rounds of the square take about a minute, the time a video call can take to connect. Because the holds set the pace, one that feels like a strain means the count is too long for you today.

How to do box breathing, step by step

Box breathing needs only a place to sit, a timer and a count you can keep. The steps below follow the instructions in a 2023 Stanford trial and a 2026 Texas State University trial, and describe a habit tested in healthy adults, not a treatment. Check the conditions listed further down before you start.

1. Sit or lie down and set a timer

Sit in a chair or lie down, and set a timer; the Stanford participants set theirs for 5 minutes. An on-screen pacer that shows when to breathe in, hold and breathe out, like the one the Texas State volunteers followed, works too.

2. Choose a count you can keep without straining

The classic count is 4 seconds per phase, the pattern used in the Texas State trial.⁶ The Stanford team instead sized the count to each person, from a few seconds up to about ten, and told everyone to shorten all four phases if they ever had to strain.¹ If 4 feels tight, start at 3. Neither trial compared counts, so a longer count has no known advantage.

3. Breathe in, hold, breathe out, hold, for the same count

Breathe in gently, through the nose if you can, and hold with the lungs comfortably full. Breathe out slowly, then pause with the lungs empty before the next breath.

1. Breathe in: slowly, through the nose if you can; recent trials used a count of about 4 seconds
2. Hold: for the same count, with the lungs comfortably full
3. Breathe out: slowly, for the same count
4. Hold: for the same count before the next breath; if any side feels like a strain, shorten all four equally

4. Keep going for a few minutes, then breathe normally

Let the timer run, then let your breathing find its own pace. The trials below all tested short sessions, so a few minutes before a meeting is closer to the evidence than a long sitting.

5. Stop if you feel dizzy, short of breath or panicky

The breaths should feel slow and easy, not deep and forced. Breathing too fast or too deep lowers carbon dioxide in the blood, and MedlinePlus lists feeling lightheaded, dizzy or unable to catch your breath among the symptoms that follow. If any of these appear, stop, breathe normally, and use a shorter count next time; if they continue or get worse, MedlinePlus advises contacting a provider.⁷

WiserHours

Before your first round

• Sit or lie somewhere I can stay still
• Set a timer for a few minutes
• Pick a count I can hold easily, 4 or less
• Keep the breaths gentle, not deep
• Stop and breathe normally if I feel dizzy or panicky

Find this checklist online:
https://wiserhours.com/mindfulness/box-breathing/#checklist-box-breathing-first-session

To try a round here, use the pacer below: it counts each side for you and moves only after you press Start.

What the trials found: calmer in the moment, no edge over mindfulness

In the two most detailed trials, anxiety was lower, or did not rise, after a session of box breathing, but the practice did not beat mindfulness meditation at Stanford, and neither trial found a change in heart rate variability. The Stanford study, led by Melis Yilmaz Balban, compared a month of daily practice with meditation.

The study

Limited evidence

Stanford, 2023: four five-minute practices for a month, and no clear win for the square

People assigned to box breathing felt less anxious and in a better mood after each daily session, as did those assigned to mindfulness meditation or to two other breathing patterns. The breathing groups together did not reduce anxiety more than mindfulness, and box breathing did not differ clearly from it on positive mood; only cyclic sighing, a pattern with long out-breaths, beat mindfulness there. No group showed a change in heart rate variability measured during sleep.¹

The mindfulness group also sat for five minutes a day, eyes closed, focused on a spot between the eyebrows, so the trial cannot show that the square adds anything over that. The groups were also small, the trial was registered only after it had run, and the wrist straps were donated by their maker, WHOOP, which took no part in the analysis; Andrew Huberman, the study’s lead contact, became an adviser to WHOOP after the data were collected.¹

A 2026 trial at Texas State University, run by Matthew McAllister and colleagues with partial funding from the US Justice Department’s community policing office, tested a single short session before a stressor: young adults recruited on campus gave a job-interview speech to recorded judges. Heart rate and anxiety climbed in those who breathed normally, but not in those who first did box breathing or took periodic long out-breaths. Heart rate variability did not change in any group, and cortisol did not differ between groups, which the authors put down to a speech task too short to raise it.⁶

Before a difficult call with a client, a few rounds of the square may keep your pulse and nerves from climbing. What the evidence does not promise is a calmer baseline weeks later.

Does the square pattern beat other ways of slowing down?

No trial has shown that box breathing works better overall than other slow-breathing patterns. The few small comparisons point one way: slowing down seems to matter more than the exact shape of each breath.

In the 2021 German lab study, healthy volunteers did a demanding attention task under time pressure and noise, using tactical breathing (counts not given in the abstract) in one condition and a long out-breath in the other. They felt no different with either; tactical breathing left them less physically aroused, and the long out-breath gave better performance.³ The Texas State team found similar effects for box breathing and periodic long out-breaths; comparing other box-breathing variants, it suggested the exact in-to-out ratio may matter less than slowing the overall breathing rate.⁶

Evidence for breathing exercises as a whole is modest and favors slow ones. Guy Fincham and colleagues pooled a dozen randomized trials in a 2023 meta-analysis: breathwork went with somewhat lower self-rated stress than comparison conditions, and in subgroup analyses split by pace, slow techniques kept that link while fast ones did not. Most of the trials had some risk of biasrisk of bias: A rating of how much room a study's design, conduct and reporting leave for its result to be systematically wrong. It judges the method, not the motives of the researchers, and a high rating means the result may be off, not that it is.Full entry in the glossary, Fincham is a trained breath teacher, and the team asks clinicians to judge case by case whether breathing exercises might aggravate a patient’s mental or physical health problems.⁸ So the square is one reasonable way to follow the slow-breathing step among everyday habits that lower stress, not the only one; the mindfulness and breathing guides cover others.

Choose the slow pattern you will keep doing.

When box breathing may not suit you, even if you are healthy

Box breathing does not suit every moment or person: in one trial the holds added strain after hard exercise, and in daily life its average benefit was small.

In a 2025 Turkish crossover trialcrossover trial: A trial in which each participant receives every condition being compared, one after another in random order, often with a gap between them. Because people are compared with themselves, fewer are needed, but the design only suits effects that wear off.Full entry in the glossary, active university students tried three ways of breathing after intense cycling; box breathing left heart rates higher than breathing at six breaths a minute, and effort felt harder than with either alternative. The authors suggest the holds added strain while the body was still working hard, and favor the even pace for recovery.⁹ A 2026 US trial of 62 cadets, read as an abstract only, points the other way on one measure: after a maximal exercise test, box breathing sped the recovery of heart rate variability compared with ordinary breathing, while heart rate recovery did not differ.¹⁰ With one trial each way, an even slow rhythm is the gentler choice between hard intervals at the gym or after a sprint for the train.

Results also varied from person to person. In a 2026 German study, physicians in training ran their own month-long experiments, alternating weeks with and without a short daily breathing exercise they had chosen. For box breathing the average change in daily stress was close to zero: a handful met the authors’ bar for a meaningful drop, while about a third had higher stress in the weeks they used it, mostly within the range of chance. Participants chose their exercise and knew which weeks were which.¹¹

The UK’s NHS offers a breathing exercise for stress with no holds: breathe in gently, perhaps counting to 5, breathe out to the same count, and repeat for at least 5 minutes.¹² If the square feels tense, try that for a week instead and notice which one you reach for.

Conditions that call for a clinician’s advice first

People with a heart condition, seizures, glaucoma, a serious mental health condition or a pregnancy should ask a clinician before trying breath holds, because the key trial of box breathing left these groups out. The Stanford trial excluded people with moderate to severe psychiatric or medical conditions that taking part could worsen, such as heart disease, glaucoma, a history of seizures, pregnancy, psychosis, suicidal thoughts, bipolar disorder or substance use disorders. Panic disorder needs its own mention: the same authors note that breathlessness is felt as a threat and that people with high anxiety or panic disorder tolerate it less well, so for them the empty-lung pause may feel alarming rather than calming.¹

When breathing trouble needs medical help

Sudden or severe difficulty breathing is an emergency, not a moment for a breathing exercise. The advice below, sorted by urgency, comes from the NHS, MedlinePlus and the NIMH (the US National Institute of Mental Health).

• Straight away: in the UK, the NHS says to call 999 or go to A&E for severe difficulty breathing, a chest that feels tight or heavy, or pain that spreads to your arms, back, neck or jaw.¹⁴ In the US, MedlinePlus advises calling 911 or going to the emergency room when breathing difficulty comes on suddenly or seriously interferes with breathing and talking.¹³ For thoughts of suicide or emotional distress, US readers can call or text 988, and should use 911 when someone’s life is in immediate danger, according to the NIMH.¹⁵ In the UK, the NHS says to dial 999 or go to A&E if a life is at risk, or to call 111 and choose the mental health option for urgent help; Samaritans take free calls on 116 123.¹⁶ Elsewhere, use your local emergency number.
• Soon: in the UK, contact NHS 111 if you are more short of breath than usual or have palpitations.¹⁴
• At a routine visit: if you live with anxiety or panic, ask your clinician whether breath holds suit you.

The bottom line

Four equal counts, a few minutes and a timer make box breathing a free, portable way to slow down. The evidence, a review of 8 trials and a few small experiments in healthy adults, supports it for short-term calm around a stressful moment, not as a lasting fix or as better than other slow breathing. Keep the count easy, stop if you feel dizzy or panicky, and ask a clinician before the holds if you have a heart, lung or serious mental health condition, panic disorder, or a pregnancy.