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sigh

There I go again, sighing. Most of the time I don’t know I’m doing it but thanks to my family I’m aware that I emit plenty of audible exhales.

My grandmother was a chronic sigher.  Each time she sat down, air rushed out of her mouth. It just seemed like an intrinsic part of her mechanism. A decade or two later my mother became a sigher as well. I should have realized the same fate would eventually strike me. I persist in thinking it’s a phase. Surely the women in my line sighed for the same reasons everyone else does—blowing off stress, expressing relief, giving in to exhaustion. Maybe they just had more than their fair share of sigh-worthy burdens.

There are good body-based reasons to sigh. When we’re stressed or fatigued our breathing is less variable. That’s not healthy. Our lungs, like the rest of our bodies, operate best dynamically. Our respiratory function becomes less efficient if we breathe in one state too long. A deep sigh resets breathing, loosening the lung’s air sacs and providing a feeling of relief.

More importantly, a deep sigh also stimulates the vagus nerve. We know all about the flight-or-flight response, which is controlled by the parasympathetic nervous system. In that state our stress hormones are turned way up. We’re jittery, impulsive, and cued to react to stress. When we are relaxed, the opposite system, the parasympathetic nervous system is active. The vagus nerve is a primary stimulator of this feel-good nervous system, operating via the neurotransmitter acetylcholine. This neurotransmitter promotes relaxation and a feeling of well-being. That’s why good deep breaths are linked to the stress-quelling results found with the Relaxation Response as well as more traditional meditation. Acetylcholine also has to do with learning, memory, even reduced inflammation. So stimulating your vagus nerve is great for brain AND body.

Not ready to sigh just yet?

Well, Dacher Keltner, psychology professor and Director of the Greater Good Science Center says that the vagus nerve is responsible for much more. Biggies like empathy and who we are as a species. In his book, Born to Be Good: The Science of a Meaningful Life* he explains that the vagus nerve,

…resides in the chest and, when activated, produces a feeling of spreading, liquid warmth in the chest and a lump in the throat.  The vagus nerve…originates in the top of the spinal cord and then winds its way through the body…, connecting up to facial muscle tissue, muscles that are involved in vocalization, the heart, the lungs, the kidneys and liver, and the digestive organs. In a series of controversial papers, physiological psychologist Steve Porges has made the case that the vagus nerve is the nerve of compassion, the body’s caretaking organ.

…Porges notes that the vagus nerve innervates the muscle groups of communicative systems involved in caretaking – the facial musculature and vocal apparatus. In our research, for example, we have found that people systematically sigh – little quarter-second, breathy expressions of concern and understanding – when listening to another person describe an experience of suffering. The sigh is a primordial exhalation, calming the sigher’s flight/flight physiology, and a trigger of comfort and trust, our study found, in the speaker. When we sigh in soothing fashion, or reassure others in distress with our concerned gaze or oblique eyebrows, the vagus nerve is doing its work, stimulating the muscles of the throat, mouth, face, and tongue to emit soothing displays of concern and reassurance.

Second, the vagus nerve is the primary brake on our heart rate.  Without activation of the vagus nerve, your heart would fire on average at about 115 beats per minute, instead of the more typical 72 beats per minute. The vagus nerve helps slow the heart rate down. When we are angry or fearful, our heart races, literally jumping five to ten beats per minute, distributing blood to various muscle groups, preparing the body for fight or flight. The vagus nerve does the opposite, reducing our heart rate to a more peaceful pace, enhancing the likelihood of gentle contact in close proximity with others.

Third, the vagus nerve is directly connected to rich networks of oxytocin receptors, those neuropeptides intimately involved in the experience of trust and love. As the vagus nerve fires, stimulating affiliative vocalizations and calmer cardiovascular physiology, presumably it triggers the release of oxytocin, sending signals of warmth, trust, and devotion throughout the brain and body, and ultimately, to other people.

Finally, the vagus nerve is unique to mammals…as caretaking began to define a new class of species – mammals – a region of the nervous system, the vagus nerve, emerged evolutionarily to help support this new category of behavior.

I’m sticking with what the body knows. I’ll be activating my vagus nerve, feeling calm and relaxed. Vagus Overusers Anonymous here I come. sigh