The basic box breath (4-4-4-4)

Breathe in four counts, hold four, out four, hold four — repeat for two to five minutes.

Why it works

The four-sided pattern slows breathing to about 3–4 cycles per minute, squarely in the range where respiratory sinus arrhythmia is amplified and parasympathetic tone increases measurably. The equal holds interrupt the tendency to over-breathe on stress and give attention a simple, predictable task — counting — that displaces anxious rumination without requiring effort or training.

How to do it

1. Sit upright or stand with feet grounded. Exhale fully to start.
2. Inhale slowly through the nose for a count of four — let the belly expand first.
3. Hold gently at the top for four counts (no strain; it is a pause, not a clench).
4. Exhale slowly through the mouth or nose for four counts.
5. Hold empty for four counts, then repeat. Run four to six cycles.

Evidence

Slow-paced breathing in the 3–6 breaths-per-minute range has robust support for increasing HRV and reducing acute stress; box breathing at 4-4-4-4 puts you in that range. (rct)

Specific RCTs on "box breathing" as a named protocol are sparse; the evidence supporting it is the general slow-breathing literature. The four-count convention is not specially studied.

Sources

• Zaccaro et al. (2018), systematic review of slow breathing and autonomic/CNS effects, Frontiers in Human Neuroscience

Common mistake

Counting too fast, which defeats the slowing effect. A useful check: four counts should take about four real seconds — slow enough that four breaths fill a minute at most.