While a sigh was previously regarded as a sign of sadness or weariness, scientists say that this is why we truly sigh: it’s a life-sustaining reflex that is vital for human being to keeps their lungs from collapsing. And unsurprisingly enough, it has nothing to do with your mood or your current emotions. As a matter of fact, people tend to sigh a lot more than they realize – studies average it at about 12 times an hour, so every 5 minutes.

But it’s become the kind of reaction people only realize they have when they only do it half-consciously – which is when the situation is dire – and thus previously only connected it to that. However, researchers from several universities such as California, Los Angeles and Stanford, have been running a thorough experiment on the neural circuitry of sighing and actually managed to find the place where sighing actually originates from in our brains.

According to Jack Feldman, neurobiology professor at UCLA and senior author on the paper that was released on this topic said that the study could lead to the discovery that some people require treatment for not sighing enough or sighing too much as the process of sighing is central to the health of our lungs.

According to the study, the need to sigh originates from a part of the brain that forces a double inhalation every now and then in order to reinflate some of the 500 million alveoli in our lungs. The alveoli are responsible for letting oxygen enter the bloodstream and carbon dioxide to be released and removed instead. These alveoli will occasionally collapse and the only way to make them functional again is to bring in a higher volume of air in so they re-expand.

But apparently the suspicions behind sighing aren’t all that new. Feldman has been studying the effect of studying on rats for several years, seeing that rodents are the only other animals who sigh regularly and even more than humans do. During his experiments, Feldman managed to get a rat to sigh up to 400 times an hour by making use of a molecule called bombesin into the lower part of its brain stem.

That portion of our brain is responsible with being the breathing control center of the body. It decides not only how fast we breathe but also what type of breath we take or how deeply we breathe: yawns, sighs, sniffs, coughs and so on. There’s yet no telling what effect sighing has from an emotional perspective and why humans and rodents seem to sigh more when stressed or upset.

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