There is a small, reliable piece of physiology that I teach in almost every session, usually without naming it. When the out-breath is longer than the in-breath, the heart slows a little. Not by much. A few beats. But the body notices, and it takes the slowing as information: nothing is chasing us, we can stop bracing.
You can feel this now, if you like. Breathe in for a count of four. Breathe out for a count of six. Do it three times. Somewhere around the second exhale, most people feel their shoulders drop by a centimetre they did not know they were holding.
Why the exhale
The inhale is effort. The diaphragm contracts, the ribs lift, the chest makes room. The exhale, in quiet breathing, is mostly release: the muscles let go and the lungs empty themselves the way a wave goes back down the sand. To lengthen the exhale is really to lengthen the letting go.
This is why I do not ask you to take a deep breath when you are anxious. A deep breath is a big inhale, and a big inhale is what the body does before it runs. I ask instead for a slow breath out. Then another.
You do not have to breathe well. You only have to breathe out a little more slowly than you breathed in.
Five and a half seconds
Researchers who study heart rhythm talk about a resonant pace, around five or six breaths a minute, at which the rise and fall of the heart rate lines up with the breath and swings widest. For most adults that is somewhere near five and a half seconds in, five and a half seconds out. The Daily Pause home page breathes at exactly that pace. You may have noticed. You may have started breathing with it.
I do not think there is anything magical about the number. It is simply slow enough to feel like rest and not so slow that it becomes a strain. If it feels like work, shorten it. The practice is to be comfortable, not correct.
People sometimes ask how long it takes before this works. The honest answer is one breath. The less honest, more useful answer is that it works better every time you do it, because the body learns that the long exhale is a door, and it starts to walk through on its own.