None of this tends to be a problem if it happens in moderation. Your body is designed to experience plenty of stress-related activation, and there’s some evidence that short bouts of stress may helpfully sharpen your focus, strengthen your memory, and provide other temporary benefits without doing any lasting damage. (If the stress response were wholly bad, your body wouldn’t engage it so readily.)
But if stress is too severe or too persistent, much can go wrong.
Chronic stress promotes low-grade, systemic inflammation, and it’s associated with an increased risk for pretty much all the major disorders of the mind and body — from anxiety and depression to heart disease. Pick a medical condition, any medical condition, and research has probably shown that chronic stress contributes to its development or makes it worse.
As researchers have studied the many overlapping risks associated with chronic stress, they’ve also identified helpful methods of stress relief or mitigation. That work has repeatedly found that Eastern wellness or contemplative practices, such as meditation, yoga, and tai chi — as well as stripped-down, Westernized versions of these activities, such as mindfulness and progressive muscle relaxation — produce potent anti-stress benefits.
While each of these practices is unique, a single unifying feature ties them all together: the breath.
Calm and controlled breathing quickly and dramatically snuffs out stress by stimulating the vagus nerve
For a 2018 paper in Frontiers in Human Neuroscience, researchers from Germany and the Netherlands explored the role of “respiratory discipline” — basically, slow and measured breathing — in the management of stress.
In that paper, they make a compelling case that calm and controlled breathing quickly and dramatically snuffs out stress by stimulating the vagus nerve.
The vagus nerve, which experts have nicknamed the body’s “great wandering protector,” is actually a lengthy, branching network of nerves that extends from your brain down into your body, where it communicates with many of your organs and systems.
Much about the vagus nerve remains a mystery, but its activity is closely linked to states of rest and relaxation.