You Sigh Without Realizing It Every Five Minutes. Here’s Why.

We sigh when we’re stressed, when we’re in love and when we practice yoga and meditation — but that’s not all. Our brains signal for us to sigh every five minutes, often without us even realizing it. (Seriously, listen to your own breaths in a quiet room, it’s like clockwork.)

Sighing, or breathing more deeply than normal, is a vital part of our everyday lives, as it helps preserve the health and function of our lungs. But exactly where our sighs originate in the brain has been somewhat of a mystery — until now.

A team of researchers at Stanford University and the University of California, Los Angeles, has pinpointed two clusters of neurons in the brain stem that are responsible for the deep exhalations, outlined in a new study published in the journal Nature on Monday.

Converting our normal breaths into sighs is regulated by the fewest number of neurons yet seen linked to a fundamental human behavior, said research co-author Dr. Jack Feldman, a professor of neurobiology at the David Geffen School of Medicine at UCLA.

“This work was very exciting to us,” Feldman told The Huffington Post. “You breathe 600 million times in a lifetime, how does the nervous system do that? … We’re hoping that in understanding breathing we can find some basic principles in how the mammalian, including human, brain is working to produce more complex behaviors.”

The researchers examined more than 14,000 gene-expression patterns in the brain cells of mice. From there, they pinpointed roughly 200 neurons in the lower part of the brain stem that contain two specific neuropeptides, which are molecules that brain cells use to communicate with each other.

Another cluster of 200 neurons contains peptide receptors that are activated by the neuropeptides, which leads to the triggering of breathing behavior.