(The most crucial nerve you didn't know you had!)
The word vagus means wandering in Latin, appropriate, as the vagus nerve is the longest cranial nerve and travels all the way from the brain stem to the colon.
The vagus nerve has a crucial role in gut-brain communication, and it's an integral part of the parasympathetic nervous system (the "rest and digest" response, basically the opposite of our "fight or flight" response).
Vagus nerve activation is involved in obesity, gastrointestinal diseases, cardiovascular diseases, mood disorders like depression, and all kinds of other chronic health problems.
The vagus nerve helps to regulate inflammation, and inflammation is involved in just about every chronic disease. So stimulating vagus nerve signals to the brain are anti-inflammatory – it signals the brain to turn down the stress response and reduce the production of inflammatory cytokines.
The effects here are a little hard to untangle because the vagus nerve is a two-way street, and there are many complicated feedback loops between the brain and the gut (remember that the vagus nerve runs both ways!). But for those of us who just care about improving our health, the exact mechanism might be less important than the impressive results:
If a bad diet is affecting the sensitivity of your vagus nerve, it could also have secondhand effects on all these diseases—one reason why gut health is such a big player in overall health.
The vagus nerve innervating the gut plays a role in controlling metabolism. It communicates peripheral information about the volume and type of nutrients between the gut and the brain. Modulation of vagus activity may alter eating behavior. In small clinical studies, in patients with depression or epilepsy, vagal nerve stimulation has been demonstrated to promote weight loss. Vagal blockade, which inhibits the vagus nerve, results in significant weight loss. Vagal blockade is proposed to inhibit aberrant orexigenic signals arising in obesity as a putative mechanism of vagal blockade‐induced weight loss. Approaches and molecular targets to develop future pharmacotherapy targeted to the vagus nerve to treat obesity are proposed. In conclusion, there is strong evidence that the vagus nerve is involved in the development of obesity. Therefore, it is proving to be an attractive target for the treatment of obesity.
An amped-up perception of stress causes lower vagal tone (or responsiveness), which means the vagus nerve has performance issues and operates at a lower capacity. If the vagus nerve isn't happy, chances are greater you won't be healthy and are more likely to age faster. Conversely, a high vagal tone is a marker of greater altruistic behavior and feeling a closeness to others.
Vagal tone is correlated with the capacity to regulate stress responses and can be influenced by breathing; its increase through meditation and yoga likely contribute to resilience and the mitigation of mood and anxiety symptoms.
We don't always have to let stressful situations negatively our minds and bodies. We can do things to stimulate our vagus nerve to send a message to our bodies that it's time to relax and de-stress, which leads to long-term improvements in mood, pain management, wellbeing, and resilience.
One of the main ways to stimulate the healthy function of the vagus nerve is through deep, slow belly breathing. You can learn to use breathing exercises to shift your focus away from stress or pain. The human mind processes one thing at a time. So if you focus on the rhythm of your breathing, you're not focused on the stressor.
When we anticipate stress in any form, most of us tend to stop breathing and hold our breath. Breath-holding activates the fight/flight/freeze response; it tends to increase the sensation of pain, stiffness, anxiety, or fear. To practice, deep breathing inhale through your nose and exhale through your mouth; remember to:
Breathe more slowly (aim for six breaths per minute).
Breathe more deeply, from the belly. Think about expanding your abdomen and widening your rib cage as you inhale.
Exhale longer than you inhale. It's the exhale that triggers the relaxation response.
Loud gargling with water or loud singing activates our vocal cords, which stimulates the vagus nerve.
Eating fiber stimulates vagus impulses to the brain slowing the gut movements and making us feel fuller after meals.
Laughter: having a good laugh lifts your mood, boosts your immune system, and stimulates the vagus nerve.
Alternate hot and cold showers. It has to be totally cold, and that hot-cold temperature variation is an excellent stimulant for the vagus nerve.
Humming and singing. The vagus nerve also supplies the throat muscles.
Yoga. Sun salutation yoga is potent in stimulating the vagus nerve.
Getting a massage or acupressure. Massage and acupressure are excellent detox activities because they open the lymphatic channels and stimulate the vagus nerve.
The last and most easily done activity that allows you to stimulate the vagus nerve is to go for long walks, preferably in nature, because nature causes the relaxation response to be triggered rather than the stress response. This is called forest bathing.
The gut, the brain, and the rest of your body are all connected. Knowing about the vagus nerve helps to explain why gut health, mental health, and whole-body health are so tangled up with each other and why good gut health is so essential for things way beyond digestion.
New, noninvasive vagus nerve stimulation devices, which don't require surgical implantation, have been approved in Europe to treat epilepsy, depression, and pain. In addition, a noninvasive device that stimulates the vagus nerve was recently approved by the Food and Drug Administration to treat cluster headaches in the United States.