The Vagus Nerve, Vagal Tone, and Vagus Nerve Activation

One of the most central topics within the gut-brain axis is the vagus nerve. Here’s why you should care about your vagus nerve, how to improve vagal nerve function, and why “toning” the vagus nerve is an important part of supporting good mental health and gut health.

The vagus nerve is the longest cranial nerve in the body. It travels all the way from the brainstem to wrap around and run alongside organs throughout the abdomen, including the lungs, the esophagus, the heart, the liver, the stomach, and the large and small intestines (just to name a few).

It both carries signals from the brain down to the heart and the digestive organs (motor signals, telling those parts of the body what to do) and carries signals back up to the brain from those organs (sensory signals, telling the brain what’s going on in your midsection). It’s mostly in control of autonomic functions – the things your body does without you having to think about it, like pumping your heart, breathing, and digesting your food.
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However, stress and anxiety affect the function of the vagus nerve pretty dramatically. When you’re in fight-or-flight mode, your heart rate and breathing speed up, and digestion slows way down. This makes good sense, since when your life is in imminent danger, you want to have adequate blood flow and plenty of oxygen to fuel your muscles, and you don’t really want to be thinking about finding a restroom.

But what about the chronic, constant day-to-day anxiety of our lives today? What about people with anxiety disorders?

In these cases, the vagus nerve’s function is thrown off balance. As a result, our heart and lungs will spend most of their time on high alert, working too hard, and our digestive system may become sluggish, leading to things like low stomach acid, gastroparesis (slow stomach emptying), acid reflux (also known as GERD), and poor digestion. Along with anxiety, this imbalance has been linked with depression, and with gut disorders such as IBS and IBD.

If you’ve struggled with chronic anxiety or an anxiety disorder, you might resonate with some of these symptoms. Perhaps your appetite tends to be poor when you are stressed, or if you try to eat you feel like the food sits in your stomach like a rock, or you develop heartburn after eating.

(On the other hand, you may have had the opposite experience, where anxiety causes your appetite to increase. This tends to be more of a learned self-soothing behavior, but doesn’t rule out having some of the same side effects of decreased vagus nerve functioning noted above.)

The important question, then, is: what can we do about this?

You may have been told by a well-meaning doctor, psychiatrist, or loved one in the past that you need to “reduce stress” or just “stop being so anxious.” These recommendations tend to be quite unhelpful and frustrating.

But there are some truly actionable ways to help close the loop of the stress cycle and harness the power of the mind-body connection to decrease anxiety.

Let’s start with the breath.

I mentioned that most of the functions of the vagus nerve are “autonomic” – meaning that they happen automatically without us having to think about them. This is true for digestion, certainly, and thankfully your heart keeps beating even if you’re not thinking about it. But breathing is different. It can and does happen automatically most of the time, but you also can control it, if you so choose.

Take a moment right now to notice the rate of your breathing. Is it fast or slow? Are you breathing through your mouth or through your nose? Are you holding your breath?

Now take a conscious, deep inhale through your nose, feeling your belly expand like a balloon as you breathe in. Count to four as you inhale; one, two, three, four. Hold it here for a count of seven; one, two, three, four, five, six, seven. And now breathe out through your mouth slowly, for a count of eight; one, two, three, four, five, six, seven, eight.

Repeat this at least four or five more times on your own, perhaps even with your eyes closed. You may notice that this is a much-needed moment of peace and stillness, and spend a few more minutes here on your own. By all means, please do.

When you have finished this short breathing practice, notice what’s going on inside your body. Has your heart rate slowed? Is your breathing a little calmer than it was when you first tuned into it?

Deep breathing, or diaphragmatic breathing, is one of the simplest ways to tap into and change the functioning of your vagus nerve. While I feel like this term is a bit too simplistic, some call it “resetting” your vagus nerve. Whatever you call it, doing breathing practices like this one regularly, you can actually strengthen its function, which is why this is called building “vagal tone.”

This can help improve heart rate variability, the ability of your cardiovascular system to respond to increases and decreases in stress levels appropriately – speeding up and slowing down to match the needs of the moment.

A lot of research is being done on VNS devices implanted to stimulate the vagus nerve for depression, PTSD, and epilepsy, among other things. However, there are some less-invasive methods you can try today.

Here are some of the other practices and tools that have been touted for improving vagal tone:

• Yoga (and other mind-body practices, like qi gong)
• Brief cold water immersion or cold showers
• Biofeedback
• Humming and singing
• Gargling
• Alternate nostril breathing (nadi shodhana pranayama)
• Acupuncture
• Massage
• Tapping
• Joyful movement
• Laughter
• A healthy diet (full of nutrient-dense foods, high in omega-3s, and with added probiotics such as from fermented foods)

Some of these practices are better researched than others. My personal favorites are eating a nourishing diet, laughter, singing along to your favorite music, and moving the body in any way that feels stress-relieving to you!

So the next time you’re feeling anxious, give your vagus nerve some love! Over time, by regularly working on toning your vagus nerve, you might find it gradually get easier to move through the stressful fight-or-flight mode and get back to resting and digesting. 

​If you’re interested in learning more about the gut-brain connection and how to improve your mental health and gut health through the power of nutrition and lifestyle, contact us or schedule a virtual telehealth appointment with Erica, a mental health dietitian! 

Note: This post may contain affiliate links. I only recommend products I love!

Erica Golden, RDN, LD, IFNCP

Mental Health, Eating Disorders, and Gut Health 
Registered Dietitian Nutritionist