4·7·8 s
4-7-8
Inhale four, hold seven, exhale eight. Physician Andrew Weil's pattern, adapted from yogic pranayama.
The protocol
Inhale through the nose for four seconds. Hold the breath in for seven seconds. Exhale through the mouth, lips slightly pursed, for eight seconds. That’s one cycle: nineteen seconds, about three breaths a minute.
The phases are fixed in the app. Start with four cycles. Don’t speed up to make the hold easier, and don’t add cycles until four feel unremarkable.
Sit or lie down for the first few sessions. If you feel light-headed, stop and breathe normally.
Best for
The last few minutes before bed. Four cycles, lights out.
Why it works
4-7-8 wasn’t designed in a laboratory, and the laboratory has only started to look at it. Vierra et al. (2022) credit the pattern to Andrew Weil, an American physician, and describe it as based on pranayama, the breath practices of yoga. Nobody has shown why it would work, and the evidence that it does anything specific is thin.
What the research does and doesn’t show
One session, two groups.Vierra et al. had 43 healthy adults aged 19 to 25, about half of them short on sleep, do three sets of six 4-7-8 cycles, and measured HRV straight after. In the group that had slept normally, high-frequency HRV power rose. In the sleep-deprived group, the time-domain HRV measures fell. Heart rate and systolic blood pressure dropped in both. Everyone did the breathing; there was no group that sat quietly instead, so the study can’t separate the pattern from simply resting.
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 4-7-8, with small to medium effects. The authors open by noting that square and 4-7-8 breathing are “popularly promoted by psychotherapists but have little empirical support.”
What nobody has tested.We could not find a controlled trial of 4-7-8 as a way to fall asleep in healthy adults (PubMed, September 2026). Easier sleep is the technique’s stated aim, which Vierra et al. note in their introduction. It is not a finding.
“None of the breathing conditions resulted in meaningful changes in blood pressure or mood.”
When to use it
The last few minutes before bed, the use the technique is taught for. Lying down, four cycles, lights out. Treat it as a routine that marks the end of the day, not as a sleep treatment; no trial supports the second.
Not a daily HRV practice. In Marchant’s comparison, six breaths a minute moved in-session HRV more than 4-7-8 did. Use resonance breathing for that, or extended exhale if you want the long exhale without the hold.
Or try a different technique