Dr. Stephen Porges on Breath, the Vagus Nerve, and Calming the Body

Watch anyone psyching up for a track meet or some other athletic contest and you'll see a pattern in how they breathe: long inhales, quick exhales. That rhythm pushes the body toward a mobilized fight or flight state. The breathing people use in yoga, or in what we might call spiritual breathing, runs the opposite way. The emphasis sits on drawing the exhalation out and on engaging the diaphragm, pressing it downward. The mechanism behind it is not complicated.

The diaphragm is where a great deal of the vagal traffic lives. Press it down and the sensory fibers, the afferent side of the diaphragm, feed into and strengthen the motor side of the vagus, the efferent pathway. The longer you exhale, the more that activity builds, and the result is calming. So when someone says "if you're stressed, take a deep breath," what they ought to be saying is "take a deep breath into your belly and let it out slowly." Being specific about it matters, and none of it is mysterious physiology.

There's a related point about movement. Watch people rocking during certain religious prayers. That back and forth motion stimulates the carotid baroreceptors, the receptors that track blood pressure, and moving the body through space along that axis ends up engaging the vagal systems too.

Eric: That's fascinating. Just to restate it for anyone listening: the long exhalation tends to settle you down, while short, fast exhalations tend to rev you up. Have I got that right?

Dr. Porges: Yes. Back when I was in high school I ran track, I was a sprinter, and I was always struck by how runners carried themselves at the starting line. Nobody was chatty or warm, no "how are you, can I help you with anything." Faces went blank, the usual social tone drained away, and there was all this huffing and puffing with the breath to get the body going. They'd rev themselves up, then rein it in as they settled into the blocks, and then explode off the line. There was a physiology underneath the behavior. It wasn't simply wanting to run fast, it was getting the body into the state that lets you run fast.

The reverse shows up in other sports. Watch a player at the free throw line: a deep breath, an exhale, then the release. Professional skeet shooters with shotguns do the same thing, managing their breath. Archers too. At the plainest level they're damping the small tremors of the body, but the reason that works is that vagal activity soothes and calms.