4·4·4·4 s
Box breathing
Inhale, hold, exhale, hold, four seconds each. Named by former Navy SEAL Mark Divine; also known as tactical breathing.
The protocol
Inhale for four seconds. Hold the breath in for four seconds. Exhale for four seconds. Hold the breath out for four seconds. Repeat. The four equal phases are why it’s called box. One cycle takes sixteen seconds, just under four breaths a minute.
In the app you can scale every phase from two to eight seconds together. Start at four. Move to five or six only after the four-count feels natural and uncomplicated.
Breathe through the nose throughout. The holds should be comfortable, never strained. If a hold turns into a struggle, shorten the cycle. If you feel dizzy, stop and breathe normally.
Best for
A structured pause before a meeting, a call, or a hard conversation.
Why it works
Nobody has shown why box breathing works, or how well. What can be documented is where it came from and what the few studies that tested it found.
Where it comes from
The name belongs to Mark Divine, a former Navy SEAL and the founder of SEALFIT. In a 2016 essay for Time, he wrote that he developed the practice to continue his breath training after the SEALs, and called it box breathing “because there are four parts of the practice.” The common line that SEALs invented it is not what Divine himself says.
The same equal-phase pattern also goes by tactical breathing, which is how Balban et al. (2023) introduce it. A German Armed Forces research team, Röttger et al. (2020), describe tactical breathing as used by military and law enforcement personnel to manage stress in dangerous situations, and note that “empirical evidence on the effectiveness of TB is limited.”
What the research does and doesn’t show
Against six breaths a minute. Marchant et al. (2025) had 84 college students breathe four ways (square, 4-7-8, and two versions of six breaths a minute) while an ECG recorded HRV. Six breaths a minute increased HRV more than square breathing, with small to medium effects. None of the four conditions meaningfully changed mood or blood pressure.
Against meditation, over a month.Balban et al. randomized participants to five minutes a day of box breathing, cyclic sighing, cyclic hyperventilation or mindfulness meditation. Box breathers reported less anxiety and negative mood after each session than before, as did every other arm. Their gain in positive mood was larger than the meditation group’s, but not by a statistically significant margin; only cyclic sighing cleared that bar.
Against a long exhale, under pressure.Röttger et al. had 30 people do a timed colour-word task under noise, using either tactical breathing or prolonged exhalation. Self-reported mood didn’t differ between the two. Physiological arousal was lower with tactical breathing; task performance was better with prolonged exhalation. The authors read it as tactical breathing suiting passive situations and prolonged exhalation suiting ones that demand action.
Our read: box breathing is a structure, not a proven lever. Its case is that it’s easy to remember and easy to do with your eyes open. That’s a real case. It isn’t a physiological one.
“Square and 4-7-8 breathing are popularly promoted by psychotherapists but have little empirical support.”
When to use it
Before a meeting, a call, a hard conversation. Five cycles at four seconds is 80 seconds, short enough to do at a desk without anyone noticing.
Not our pick for a daily HRV practice: in Marchant’s comparison, six breaths a minute moved in-session HRV more, so use resonance breathing for that. Not our pick for the last minutes before bed either; we’d use 4-7-8 or a plain extended exhale.
Or try a different technique