It comes as natural and we don’t really think about it, but sighing is actually vital for the lungs to keep up normal breathing patterns without us even realizing.
- Humans sigh an average of 12 times per hour
- Researchers found a neuropeptide that influences sighing, and its region in the brain
- There are around 200 neurons that trigger the reflex of sighing
- A sigh brings in twice the amount of air, which helps in maintaining the well functioning of our lungs
A sigh can be an emotional response to many things, ranging from dreaminess to disapproval, disappointment, or frustration. However, we actually do it much more often than we realize. Most of us reportedly sight around 12 times per hour without realizing it, taking that much needed “double breath” that our lungs require. It’s an involuntary reflex, and just as mysterious as it is common.
Two researchers delved further into the matter after identifying a type of neuropeptide that influenced the way rodents sigh. It’s a protein-like molecule used by the brain in communication, though it seems to be affecting breathing to a degree as well. Jack Feldman, from the University of California, Los Angeles (UCLA) conducted an experiment by either injecting the peptide or repressing its receptors in mice.
By artificially introducing the compound into the brains of the rodent subjects, it increased the rate of sighing from 40 times to 400 times per hour. When the receptors for the peptide were repressed, the mice stopped sighing altogether. However, it didn’t appear to affect their normal breathing patterns.
Feldman’s research was paired with Mark Krasnow’s from Stanford University, and they managed to find the precise region in the brain that controls sighing. According to co-author of the study, Krasnow, the brain’s breathing center not only regulates how often we breathe, but what type of breath we take in. Sighing is in a different category, as it requires the lungs to take a double breath. Why this happens is vital for our regular breathing.
The lungs have around 500 million little balloon-like sacs where the oxygen enters the bloodstream, and the carbon dioxide is pushed out. These are called alveoli. Each one in particular is barely two tenths of a millimeter wide, but together they could cover the surface area of a tennis court. According to the researchers, these alveoli “barely ever” collapse. However, given that there are half a billion of them, that’s still a relatively high number.
When one of them crashes, the signal is sent to our brain to sigh. The extra gust of air we inhale beyond our normal breathing helps the alveoli recover. This is because sighing brings in twice the amount of air. It’s more than just a reaction to emotional stimuli, but it’s actually a physical need that is paramount to breathing.
And according to the researchers, there are just around 200 neurons that carry out the task of triggering the reflex. At the very least, this is the case in rodents, which have been showed to have both brains and respiratory systems similar to our own. So, you may not be aware of it, but you’re sighing no matter your mood. Or very likely while reading about it, as it happens with most involuntary reflexes.
Image source: gooverseas.com