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The Connection Between The Vagus Nerve and Stress

Stress is a well-documented major contributor to disease, degeneration, and aging. Compared to our ancestors who lived peacefully in sync with the natural cycles of nature, we have created a culture that has replaced beneficial physical stress (i.e. exercise) with unsustainable levels of mental and emotional stress.

With each stressful mental and emotional experience, we change the way we breathe. Every worry, regret, unfulfilled desire, and the emotions that come with them force us to take a more shallow, upper-chest breath. This activates receptors in the upper chest to trigger a fight-or-flight response. While this reaction will save your life in the face of short-term danger, it can be extremely degenerative in the long term. With chronic stress comes a chronic degenerative response that is initially triggered by a simple shift in how we breathe. Think of a gasp when you see a bear in the woods, or a spider or mouse in your home.

To protect the body from out-of-control fight or flight stress, the body employs a cranial nerve called the vagus nerve. Known as the “wandering nerve”, it travels from the brain to the lower abdomen. It acts as a firefighter, putting out fires and turning off unnecessary alarm bells caused by stress throughout the body. As it travels, it wanders, innervating almost every major organ and gland of the body, making sure that stress is not allowed to run rampant anywhere in the body.

The vagus nerve governs the parasympathetic nervous system (also known as the “rest and digest” nervous system). There are many Ayurvedic techniques that stimulate the parasympathetic nervous system via the vagus nerve, such as yoga, breathing, meditation, daily self-massage, chanting, humming, singing, and many more. It can be said that any relaxation technique can stimulate the vagus nerve and help combat stress. In this article, I will only touch on those techniques that are backed by science.  

Effective Electrical Vagus Nerve Stimulation

For years now, medical doctors have been using vagal stimulation for depression and epilepsy with great success. Early vagal stimulation required implanting electrical stimulation devices under the chest, with a wire inserted behind the left ear to stimulate the vagus nerve.  Today there are hand-held, FDA-approved, non-invasive vagus nerve stimulators that have been studied to effectively stimulate the vagus nerve. Studies have shown that placing a small vagal stimulator below the ear and behind the jar bone can effectively stimulate the vagus nerve.

The Hoolest VeRelief is one such device. Studies done with the handheld VeRelief PRIME found that stimulating the vagus nerve for 1-2 minutes a day delivered the following results:

• 100% reported treatment was relaxing
• 36% decrease in state-anxiety
• 31% increase in parasympathetic activity (HRV)
• 31% improvement in heart rate variability, a measure of relaxation under stress
• Supported healthy sleep cycles
• 0 differences in safety and tolerability compared to the placebo group

How Does It Work for Sleep, Stress, and Anxiety?

The auricular branch of the vagus nerve (ABVN) runs just under the skin below the ear and along the jawline. This location makes it very accessible for minimal stimulation. The ABVN region below the ear stimulates the brain’s reticular activating system: where serotonin and norepinephrine are produced. This is how topical stimulation of the vagus nerve can be so effective in helping you fall asleep faster, easing racing thoughts, reducing stress and anxiety, and even improving your mood. 

Listen to Dr. Douillard’s podcast interview with Dr. Nick Hool, the inventor of the VeRelief, on the research behind vagus nerve stimulation. 

Vagal nerve stimulation with the VeRelief Prime has been shown to increase vagal tone by increasing heart rate variability (HRV). When stress levels are high, HRV (the space between each heartbeat) increases. When stress levels are low and the parasympathetic system is activated, HRV levels drop. Directly stimulating the vagus nerve where it is most accessible with safe topical electrical stimulation is perhaps the quickest way to access symptomatic relief. However, there is evidence that the following Ayurvedic pranayama practices are also powerful methods for accessing the vagus nerve. These breathing techniques take time to work, but they also train the nervous system that it is safe to turn off the fight-or-flight system. 

Nose Breathing to Stimulate the Vagus Nerve

One of the best ways to stimulate the vagus nerve is to breathe deep enough and slow enough to stimulate the vagus nerve as it passes through the diaphragm. This happens naturally when you breathe through the nose consistently. Our study, in which we compared nose breathing to mouth breathing during exercise, showed that nose breathing during exercise increased parasympathetic activity while lowering sympathetic (fight or flight) activity. Nose breathing exercisers also saw meditative alpha brain wave activity, suggesting a neurological calm during sub-maximal exercise. These results stand in contrast to the mouth-breathing exercisers, who produced predominantly beta brain wave activity (which is an indicator of stress).

See also How Nose Breathing Gets Athletes in the Zone

Strengthening the Diaphragm to Stimulate the Vagus Nerve

Shallow breathing because of inactivity, sitting, and slouching has become a chronic condition that I see clinically on a daily basis. The diaphragm, when fully contracting and relaxing, has a powerful effect on activating a relaxation response via vagal stimulation. Sadly, in a recent study,  91% of athletes tested had dysfunctional breathing patterns where their diaphragm was not relaxing and contracting fully. Suppose the athletes of the world do not have healthy diaphragmatic functions. In that case, it is safe to assume that most of us do not either, thus the need for regular diaphragmatic exercise and vagal stimulation.

I have written many articles on nose breathing, pranayama, and how to strengthen the diaphragm. To get started, I have compiled an article on the Best Diaphragmatic Exercises. There are 3 video tutorials there that will help to free up and strengthen your diaphragm.

Refining Ujjayi Pranayama for Vagal Stimulation

Ujjayi pranayama is also known as the ocean breath or “Darth Vader breath” because as you inhale and exhale, you slightly constrict the back of the throat, creating a sound as if you were breathing through a respirator.

To use this breathing technique to stimulate a vagal response, you must fully extend the exhale. When making the ujjayi breathing sound on a full exhale, you will notice that in order to continue to make the resonating sound of ujjayi, you MUST contract the abdomen. When you exhale fully and naturally contract the abdomen, you trigger an abdominal—diaphragmatic—cardiac “massage”.  By contracting the abdomen and then the diaphragm, this then pushes up on the heart, triggering the vagus nerve as it passes through all of these structures. It was this effect that seemed to cause the results in our nose vs. mouth breathing study mentioned above and in my book, Body, Mind, and Sport. 

Note: Use ujjayi only during the exhale during exercise and use both inhale and exhale prior to meditation.

Tip: Go for a walk/hike. Breathing maximally in through the nose and maximally out through the nose. Use ujjayi to engage in a maximal exhalation feel the abdomen fully contract, and enjoy an effortless vagal stimulation exercise.

Humming (Brahmari Pranayama) to Stimulate a Vagal Response 

There are many studies suggesting there are powerful hidden health benefits in singing, chanting, and even humming. Those who practice these techniques know this to be true. Now, research shows that the studies that link these practices are linked to increased parasympathetic activation via vagal stimulation. Let’s look at a pranayama breathing technique called brahmari (the humming or bee breath). In one study evaluating brahmari,  23 participants were monitored during sleep, physical exercise, emotional stress, and the practice of brahmari. Heart rate variability (HRV) was used to measure the level of parasympathetic activity or vagal activation. The humming during brahmari produced more HRV (relaxation) than any of the other activities tested. The study concluded that a regular daily humming routine can help enhance the parasympathetic nervous system and slow down sympathetic activation.

See also Dr. Douillard’s Full Article on All the Benefits of Brahmari Pranayama 

Cold Exposure to Boost Vagus Nerve Activation

Cold showers, ice baths, or dipping your face into cold water have also been shown to increase parasympathetic activity over time. The first response to cold exposure is actually an increase in sympathetic (fight-or-flight) activation. However, once the body acclimates, the sympathetic activation drops and parasympathetic (rest-and-digest) activity increases. The more you acclimatize to being in the cold, the more parasympathetic tone is produced.

Cold plunge acclimatization slowly trains the brain that the body is quite safe in these cold temperatures. Sadly, because of our desire for comfort, we have acclimatized to the room temperature of 72 degrees F and feel stressed on either side of that. It is a good practice to train the body to tolerate heat with saunas and to tolerate cold with cold water exposure. Overall, combining Ayurvedic nose breathing practices with cold exposure is a great way to activate your parasympathetic nervous system, and new technology like the VeRelief offers fast activation of the vagus nerve. In a fast-moving modern world that often triggers our stress responses, these techniques are important methods of maintaining long-term health.