Have you ever noticed that when you are feeling stressed out, that taking a few deep breaths, or stretching, or reaching out to hug a friend or loved one, provides almost instant relief? We all do these kinds of things in response to a stressful situation, and they all can provide a similar calming effect.

That is because each of the actions described, all stimulate the vagus nerve.

The vagus nerve is one of the twelve cranial nerves, which sprawl out from the brain and into the body like an intricate network of roots. These nerve networks act as lines of communication between the brain and the body’s many systems and organs. Some of the cranial nerves interpret sensory information collected by the skin, eyes, or tongue. Others control muscles or communicate with glands.

Vagus is Latin for “wandering,” which is apt when one considers all the different parts of the body the vagus nerve reaches. “It seems like every year somebody finds a new organ or system that it talks with,” says Tiffany Field, PhD, director of the Touch Research Institute at the University of Miami School of Medicine.

Field says that branches of the vagus nerve are connected to the face and voice. “We know that depressed people have low vagal activity, and this is associated with less intonation and less-active facial expressions,” she explains. A separate branch of the vagus nerve runs down to the gastrointestinal tract. Here, low vagal activity is associated with slowed gastric motility, which interferes with proper digestion, she says.

In fact, experts have linked the activity of the vagus nerve to symptom changes in people with migraine headaches, inflammatory bowel disease, depression, epilepsy, arthritis, and many other common ailments. The more science learns about the vagus nerve, the more it seems like a better understanding of its function could unlock new doors to treating all manner of disease and human affliction.

Inflammation is the Key

There is a current avenue of medical thinking that believes that systemic inflammation is responsible for most, if not all disease conditions, even aging. This theory could explain why the activity of the vagus nerve is so critical to health and well-being. The nerve’s activation or deactivation is tied to the ebb and flow of hormones such as cortisol and the digestive hormone ghrelin – both of which influence inflammation.

Cortisol, in particular, is known as the “stress hormone.” High levels of cortisol are released when you are stressed. Elevated cortisol levels have been linked to everything from obesity, to back pain, to diabetes and Alzheimer’s disease. The link between cortisol and all of these conditions is increased systemic inflammation which throws off the immune system and equilibrium of the gut microbiome.

As indicated in the opening, the vagus nerve is intimately related to our reactions to stress, and the activation of the “fight or flight” response.

The vagus nerve triggers all of the body’s relaxation responses. In simple terms, heightened vagal activity counteracts the stress response, which involves the sympathetic nervous system. “The sympathetic nervous system is fight or flight, while the parasympathetic nervous system is more chill out,” says Stephen Silberstein, MD, a professor of neurology and director of the Headache Center at Philadelphia’s Thomas Jefferson University Hospitals.

Silberstein has been involved in research that is using directed stimulation of the vagus nerve to successfully treat conditions such as asthma and epilepsy. He says, “Pick almost any common medical condition that’s made worse by stress or inflammation — everything from arthritis to inflammatory bowel disease — and there’s research showing that vagus nerve stimulation can help treat it or relieve its symptoms.”

Silberstein also says that while his research is showing how external stimulation of the vagus nerve can treat disease, ways that you can trigger its relaxation response on your own, can help prevent inflammatory disease.

He says that stress reduction activities such as yoga, meditation, tai-chi, and or deep breathing, improve health and well-being, through increased vagal activity.