How Does a Physiological Sigh Cut Stress So Fast?

Andrew Huberman says the physiological sigh cuts stress the fastest while a person is still engaged in life. A breathwork class or a weekend at Esalen is a magical experience, but stress hits when life demands press in. Vacation, long meditation retreats, massages, and a nice drink, for anyone of drinking age, still work, but they are slow and take a person offline.

Physiologists discovered the pattern in the thirties. Professor Jack Feldman at UCLA, a world expert in the neurobiology of respiration, and Andrew Huberman's colleague Mark Krasnow at Stanford, who studies lung function, later rediscovered it. In deep sleep, when carbon dioxide in the bloodstream gets too high, people and dogs do a double inhale followed by an extended exhale. Sobbing children and adults do the same double inhale and exhale. It relaxes because it offloads a lot of carbon dioxide at once. Lungs are not two big bags of air. Millions of little sacks, laid flat, would cover about a tennis court, so the volume of air and carbon dioxide they can offload is tremendously high. Under stress, carbon dioxide builds up and the sacks deflate. A double inhale, best through the nose though the mouth also works, sneaks in a little more air at the end and reinflates the sacks. The exhale discards the carbon dioxide all at once. Unless a person is underwater, a double inhale followed by an extended exhale offloads the maximum amount of carbon dioxide.

Huberman's laboratory and other laboratories found that just one, two, or three physiological sighs bring stress down very, very fast.