The drawn-out exhalation we know as a sigh doesn’t just telegraph emotion. It’s also a vital reflex that keeps us from suffocating.
Researchers have now isolated the clusters of neurons in the brain stem that turn a simple breath into a sigh. (And yes, that’s the term scientists use for it, too.) Finding it is an important step toward treatments for people who can’t regulate breathing on their own.
This elusive mechanism has turned out to be a stunningly simple reflex. “Sighing appears to be regulated by the fewest number of neurons we have seen linked to a fundamental human behavior,” said Jack Feldman, a neurobiology professor at the University of California, Los Angeles, in a press release. Feldman is an author of a new paper in Nature documenting the discovery, made by a team of researchers from UCLA and Stanford University.
Consciously or not, we sigh about every five minutes. Those exaggerated breaths take in twice the normal volume of air and reinflate the alveoli, the tiny sacs in the lungs where oxygen and carbon dioxide exchange. When the alveoli collapse, only a sigh will reinflate them.
Artificial ventilators mimic the action of a sigh. The new discovery could help develop medications that train patients’ brains to sigh on their own.