The short version
A normal inhale through the nose, then a second, shorter sip stacked on top, then 1 long, slow exhale through the mouth, longer than both inhales combined. About 4 seconds. Repeat 1 to 3 times, then breathe normally. The fastest reset in the book for a single sharp jolt.
What the research says
The best-supported single breath in this field. A 2023 Stanford trial (108 enrolled, 100 analyzed) found five minutes a day of cyclic sighing improved mood and lowered resting breathing rate over a month; it was not clearly better than box breathing in the same study. Cited under Chapter 2.
Rooms where it does the work
Two rules, no exceptions
Never practice any technique on this site while you are driving, operating machinery, or doing anything that needs your full attention. The slow ones can make you drowsy, faster than you’d expect. And never practice a breath-hold, bellows breath, or any vigorous breathing in or near water. Read Before you begin for the doctor’s list and the rest.
The short version is a reminder, not a lesson. The chapter has the story, the steps, the mistakes, and the limits.