How Vagus Nerve Stimulation Impacts Digestion and Mental Health: Part One in the Series
The vagus nerve — the longest cranial nerve in the body — is finally getting the attention it deserves. Not just because the vagal nerves are involved in essential bodily functions like digestion, mood, speech, and respiration, but because vagus nerve stimulation (VNS) is shown to be a promising adjunct treatment for many physical and mental health concerns (and the digestive issues that often accompany them).
Take anxiety and depression, for example. About 60 percent of individuals with anxiety and depression experience gastrointestinal disturbances like irritable bowel syndrome (IBS); stress can further exacerbate these symptoms. Studies also show that those with irritable bowel syndrome (IBS) frequently experience anxiety and depression in addition to GI symptoms such as diarrhea, constipation, abdominal pain, and bloating.
Stimulating the vagus nerve; however, is shown to benefit the brain as well as the gut. It can even improve sleep quality (which also affects our mental health and digestion, by the way!).
But what exactly does it mean to “stimulate” the vagus nerve? And how can we possibly stimulate a nerve that runs from the brain all the way down to the large intestine? It is possible, and there are lots of vagus nerve exercises we can try from home. These exercises can help to improve the health of the vagus nerve (known as the vagal tone), strengthen the connection between the gut and brain, and reduce gastrointestinal symptoms.
As part one in my Digestion and Mental Health Series, this blog focuses on the vagal nerves and their impact on the gut. Read on to learn how to stimulate your vagus nerve for improved digestion and psychological well-being.
The Parasympathetic Nervous System & Vagal Nerves
While the purpose of this blog is to share a few of my favorite vagal nerve exercises for digestion, let’s first take a quick look at the connection between the parasympathetic nervous system (PSNS) and vagus nerve. Both are integral parts of the body’s autonomic nervous system (ANS), working together with the sympathetic and enteric nervous systems (ENS) to control various “automatic” processes in the body.
As the main nerves of the PSNS — the network of nerves responsible for digestion and other processes like defecation, urination, and sweating — the vagal nerves travel down the right and left sides of the body. They send signals in both directions, allowing the gut and brain to communicate with one another. This pathway is more commonly known as the gut-brain connection, gut-brain axis, or gut-brain crosstalk.
When the gut and brain don’t communicate as they should; however, gastrointestinal disturbances can occur. Disruptions in the gut-brain axis are also thought to be involved in the development of “functional” gastrointestinal disorders (FGIDs) like IBS and gastroesophageal reflux disease (GERD).
Furthermore, since the vagus nerve makes up about 75 percent of the parasympathetic nervous system, engaging in manual or electrical activities that stimulate the vagal nerves also activates the PSNS — the part of the nervous system that’s responsible for promoting the body’s “rest and digest” response. This, in turn, calms the sympathetic nervous system (SNS) — the network of nerves that control the body’s “fight or flight” response — reduces stress and anxiety, and improves digestive issues like abdominal pain or diarrhea.
Vagus Nerve Exercises for Digestion
When we engage in activities that stimulate the vagal nerves, what we are essentially doing is increasing the vagal tone and improving the gut-brain connection (the communication between the brain and gut). Here are five vagus nerve exercises to improve the gut-brain axis, reduce symptoms of anxiety and depression, and boost gut health.
1. Diaphragmatic Breathing
While breathing is an automatic process that’s controlled by the autonomic nervous system, there is a right and wrong way to do it. And unfortunately, most of us are doing it incorrectly. We tend to breathe through our upper chests and with our mouths open, when what we should be doing is breathing through our abdomens. I’m talking about deep belly breaths where we can actually see our abdomens rising and falling.
Known as diaphragmatic breathing, this style of deep breathing activates the parasympathetic nervous system, improves heart rate variability (HRV), and stimulates the vagus nerve for improved vagal tone. It’s something we can do anywhere and at any time, and it’s one vagus nerve exercise that has an instant effect on physical and mental health.
One study even showed that diaphragmatic breathing could improve sustained attention, reduce negative affect, and lower cortisol levels. Another showed that six weeks of deep breathing could enhance vagal activity and reduce symptoms associated with constipation-predominant IBS.
2. Cold Water Exposure
As unpleasant as it may sound, cold water exposure can do wonders for the vagus nerve and parasympathetic nervous system. One study, for instance, found that 15 minutes of cold-water immersion reduced stress, anxiety, depression, muscle aches, and cortisol hormone levels among elite athletes. Another study published in Aviation, Space, and Environmental Medicine found that repeated whole-body cold water exposure could decrease the sympathetic response and increase parasympathetic activity.
That being said, research also tells us you don’t necessarily need to do a cold-water plunge to reap these benefits. A more recent study published in JMIR Formative Research found that cold stimulation at the lateral neck area specifically could activate the parasympathetic nervous system. So don’t feel the need to fill your bathtub with ice water just yet (unless that’s your thing, of course!).
If you’re not up for taking a cold bath or shower (I get that), simply washing your face and neck with cold water or placing a cold pack on the back of your neck will do the trick. Other ways to stimulate the vagus nerve include placing a cold pack on your chest, ending every shower with a blast of cold water, and drinking ice water.
3. Gargling, Humming, & Singing
There’s a good chance doctors have been testing your gag reflex for as long as you can remember. But do you know why they do it? It’s to test cranial nerve X (AKA the vagus nerve!). Activating the gag reflex stimulates the vagus nerve and engages the larynx; however, it isn’t your only option (thank goodness for that!).
Some other vagus nerve exercises that engage the larynx and vocal cords include:
- Gargling with water whenever you brush your teeth.
- Humming a tune.
- Singing along to your favorite songs.
- Laughing out loud.
4. Interval Training & Tai Chi
It’s no secret that exercise improves mental health and well-being, but did you know it increases vagus nerve activity as well? It’s true! One study showed that vagal nerve activity increased significantly after the cessation of moderate-intensity interval training, while another found that tai chi exercise may enhance vagal modulation. Tai chi is also shown to improve symptoms of IBS with constipation, particularly in symptom severity, quality of life, and abdominal diameter.
A third study looked at the effects of mild exercise on vagal nerve regulation in rats. Researchers found that after mild physical activity, the vagus nerve “stimulates gastric motility and enhances the ability of the stomach to process food.” (Ye Wang, et. al., 2010). The study also suggests that mild physical activity enhances the gastrointestinal tract’s ability to process food and absorb nutrients from food. This is super important since vitamin deficiencies can negatively affect our mental health, digestion, and overall well-being — including deficiencies in vitamin B, vitamin D, and choline.
5. Mindful Eating
You might remember from my intuitive eating and mental health blog that our eating habits (like overeating or not eating enough) can either harm or support our mental health. But eating mindfully is just as important as eating intuitively, especially when it comes to vagus nerve stimulation.
Mindful eating — the practice of staying present during mealtimes and focusing on the textures, tastes, smells, and other characteristics of the food we’re eating — reduces stress, activates the parasympathetic nervous system, and improves digestive function. It can also help those with digestive disorders like IBS to identify their food triggers, chew food more thoroughly, and avoid overeating. Better yet, we can pair mindful eating with a few moments of diaphragmatic breathing to give the vagus nerve a double dose of love at mealtimes.
Stay Tuned for More Blogs in My Digestion & Mental Health Series
As my Digestion and Mental Health Series continues, we’ll be looking at a few of the different ways in which digestion affects mental health (and vice versa). Stay tuned as the series continues, and in the meantime, try these five vagus nerve exercises to alleviate digestive issues, reduce stress, and activate your body’s “rest and digest” mode for improved physical and mental health!
Ready to nourish your body, mind, and soul with functional and integrative therapies like nutrition, mindfulness, sleep, movement, and genetics testing? Start by learning more about holistic mental wellness or apply for private coaching.