We Sigh All Day Everyday, Yet it's Still a Mystery
Researchers know some physical reasons to explain sighing, but are lost about it's relationship to our emotions
Hiya
So, apparently, I sigh a lot. Over the years, I’m frequently asked by friends, roommates, coworkers, and acquaintances whether I’m okay. They often interpret my sighs as annoyance or frustration, but I always respond, “I’m good, just breathing.” Most of the time, I’m completely oblivious to my sighs until someone asks if I’m okay.
Since it’s been brought to my attention, though, I’ve found that more often than not, I sigh when I’m trying to understand something or am deep in thought, which is often. Of course, I also sigh when relaxed, full after a meal, bored, or sleepy. But it’s not like I’m the only one. Everyone sighs, and we do it for all sorts of reasons. Yet, amazingly, researchers understand shockingly little about why we sigh at all.
Sighing
Did you know that, on average, we sigh about twelve times in an hour, or about once every five minutes? That’s a lot! I know I sigh often, but that’s more than even I expected and suggests that sighing is more important than we realize.
How can such a small act be so important, and in what way is it important? In this sense, experts have come relatively far. They’ve learned a lot about the physical effects of sighing, including the influence it has on our brains and lungs. But sighing has a strong connection to our emotions, too — and that link remains a mystery.
Sighing in the brain
Our brains are remarkable machines, capable of far more than we realize or understand. Yet, according to an article by UCLA Newsroom, a professor of neurobiology at the David Geffen School of Medicine at UCLA and a member of the UCLA Brain Research Institute, Jack Feldman, discovered that,
“Sighing appears to be regulated by the fewest number of neurons we have seen linked to a fundamental human behavior. One of the holy grails in neuroscience is figuring out how the brain controls behavior. Our finding gives us insights into mechanisms that may underlie much more complex behaviors.”
In 2016, Feldman and Mark Krasnow, a professor of biochemistry and Howard Hughes Medical Institute Investigator at the Stanford University School of Medicine, teamed up and discovered the neurons responsible for sighing in the brain. Each of the few neurons regulates not just how fast we breathe but also the form our breaths take. Krasnow explains in the same article as above,
“It’s made up of small numbers of different kinds of neurons. Each functions like a button that turns on a different type of breath. One button programs regular breaths, another sighs, and the others could be for yawns, sniffs, coughs and maybe even laughs and cries.”
I don’t think I considered all the various forms our breath can take. Nor did I notice the many ways our breathing reflects our emotions or state of mind, but of course, it does! Though sighing serves another, perhaps, more important purpose than conveying how we feel. It turns out that sighing is mightily important to our lung health.
Sighing in the Lungs
See, there are half a billion tiny air sacs called alveoli covering our lungs, which exchange oxygen and carbon dioxide when we breathe. But sometimes, the alveoli collapse, which is when sighing comes in.
As you know, a sigh is like a regular breath, except it includes a second inhale before exhaling — and it’s the exhale that we call a sigh — usually followed by a pause before returning to our regular breathing pattern. This oxygen boost helps reset the collapsed sacs so they can continue exchanging O2 with CO2. Feldman explains that when our alveoli sacs collapse, which they’re prone to do regularly,
“The only way to pop them open again is to sigh, which brings in twice the volume of a normal breath. If you don’t sigh, your lungs will fail over time.”
In fact, sighing is so essential to our respiratory health that ventilators programmed to include sporadic sighing actually improved the lung health of patients using the machines. More specifically, research shows that including sighs in the ventilation patterns actually improved Gas Exchange and Lung Volume in Patients with Acute Respiratory Distress Syndrome.
The frequency of our sighs makes sense between the minimal neuronal activity and the relationship between our lung health and sighing. Knowing the physiological reasons for sighing might have once been enough, but the context of our sighs indicates there’s more to it.
After all, on the one hand, sighing is almost autonomic — we do it without even realizing we’re doing it. But on the other hand, as I mentioned earlier, we also sigh intentionally to convey our emotions. And it’s the link between sighing and our emotions that is proving far more elusive than the physical properties behind it.
Emotional Sighing
No doubt you’ve experienced the emotional release a quality sigh can provide, especially in moments of stress or high anxiety. I swear sighing helps me think or gather my thoughts, though I have no research to support my hypothesis.
However, study after study over the years, including as recent as 2022, suggests we sigh more often while experiencing “negative emotional states,” including fear, sadness, and anxiety, but also during pain and arousal.
Some research suggests that sighs are usually unintentional expressions of an activity, desire, or plan that has to be scrapped and create a pause so a new novel initiative can replace it.
Yet despite all the research showing that sighs are basic forms of self-expression, the mechanisms behind conscious sighing and our emotions remain elusive.
Perspective Shift
Discovering the physiological reasons and biology behind sighing shows how vital sighs are for our health, which is fascinating in itself. Though, of course, you know I love a mystery, and the fact that sighing also possesses an emotional component tickles my brain.
Less so that we don’t understand the connection, which makes sense since emotions remain largely mysterious in their own right. What I find impressive is how we’ve adapted practically every feature and function within our control to convey what’s going on within us.
Sighing, which likely evolved to aid our lung health, was adapted as a way also to convey our emotions and even offer relief from the ones causing us distress. Maybe this just shows how efficient we are as a species, or perhaps our intense desire to connect with others.
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