What is the Vagus Nerve and What Does it Do?

What is the Vagus Nerve and What Does it Do?

Picture this: It's Monday morning, your alarm blares, your eyes snap open and your heart starts racing. You're just as tired as you were when you went to bed last night (and sometimes even more tired, I mean how is that even possible). The world feels like a relentless whirlwind of stress and chaos, and you're either already running through your to-do list for the day or burrowing your head under the covers until your next snooze alarm attempts to wake you (but it wouldn't dare).

Sound familiar? Well, you're not alone. This used to be my reality, one that I escaped but know very well. In today's fast-paced, results-driven, metrics-based world, how can we not feel overwhelmed from time to time? And if we're not careful, “from time to time” quickly becomes all the time.

When I say you're not alone, you're really not alone. Your body contains microbes, organs, cells, communication systems, storage centers, analysis hubs, and even its own waste management system. As advanced as our society's scientific knowledge is, we continue to learn more and more about the complexity of the human body each and every day, and at an exponential rate. We've started connecting the pieces, exciting pieces, building bridges across what we thought were islands, mapping out a system more complex than we could have imagined. Interdisciplinary research teams are forming, and new fields like psychneuroimmunology and neuromicrobiology are being born.

In all the noise, no matter where you go, even when you're at your most alone…know that you have an ally with you always. There's a hidden hero within you, silently working to keep you calm and centered amidst the chaos - the mighty vagus nerve.

The vagus nerve is one of the longest nerves in the human body, running from the brain to various organs such as the gut, heart, and lungs and communicating with them all at lightning speed. It plays a crucial role in regulating the parasympathetic system, also known as the "rest and digest" system¹. Our vagus nerve is what calms us down by regulating our breathing, stimulating digestion, and informing our heart to slow back down to a normal speed.

Our vagus nerve is what takes us from a tense, numb, scared, anxious, angry or otherwise emotionally-activated or dissociated state to what is informally known as “social engagement mode”, which essentially handles higher-order cognitive functions such as empathy and long-term planning². When we're in social engagement mode, we feel comfortable around others, not threatened or on edge. Our brains are ready to connect, create, and learn. We feel safe.

Wait, social engagement sounds awesome! Why don't we just stay in it all the time? Well…the vagus nerve has a side hustle. And that side hustle is to activate our “fight-or-flight” response; in other words, it turns on our sympathetic nervous system and sends messages throughout our entire body to let all our cells know WE ARE IN DANGER. During this reactive response, our heart rate increases alongside our blood pressure and breathing, redirecting blood flow from the digestive system to prepare us for action³. Our body starts shutting down higher executive functioning and anything “extra” (like digesting), because we need to focus all our bodily resources on running from this threat or fighting it! There will be plenty of time to digest our food later if we survive this!

Keep in mind: our ancestors faced threats in the form of lions, tigers, and bears, not lengthy corporate emails sent in the middle of the night by Susan when she knows you are on vacation. But to our vagus nerve, a threat is a threat. The sympathetic nervous system and its fight-or-flight suite of symptoms continue until the perceived danger has passed, and which point the vagus nerve reactivates “rest and digest” mode. The parasympathetic and sympathetic nervous systems work together to ensure our survival, enabling our bodies to react automatically to potential threats with almost no conscious effort. But what if the perceived danger never passes?

The vagus nerve is highly sensitive to instances or perceptions of threat. Generally, as human evolution intended, this is a good thing. This is what kept our ancestors alive. Ideally, we want our parasympathetic and sympathetic nervous systems to be in homeostasis, which is a fancy word for balanced. But considering that this modern world is filled to the brim with injustice, overstimulating media, existential threats, and basically every danger you could possibly imagine except aliens (so far), it's become very difficult to achieve this balance.

That racing heartbeat on a Monday morning or the sinking feeling in your stomach after watching the news or scrolling on your feed — that's a sign of your sympathetic nervous system in action. Your body's natural defense system has interpreted a threat from your environment and is alerting you and preparing you for impending danger. It’s possible that many of us are experience chronic over-activation of this system, which can have detrimental effects on our mental health. We love a side hustle, but in this case…when your vagus nerve's side hustle becomes its main hustle, it's time to give your vagus nerve a little support.

One indicator that the vagus nerve is functioning poorly is referred to as having a low vagal tone. When we have low vagal tone, its activity has measurably decreased, leading to the parasympathetic nervous system being under-activated. This can make it even harder to achieve a balanced nervous system. Heart-rate variability (HRV) is measured, sometimes alongside breathing rate, as an indirect measure of vagal tone, but there is debate as to whether HRV is actually a good proxy for vagal activity⁴. It would likely be much more useful and practical to simply observe how your body feels when you're emotionally active, especially when you are experiencing stress. If you find yourself to be constantly shifting among fight, flight, freeze, or fawn, but can't remember the last time you felt at ease and totally safe, with no lingering feeling of impending doom…your vagus nerve has got you stuck in that parasympathetic-activated state.

The other limitation of trying to measure vagal tone and determine whether your vagus nerve is functioning properly is this: your vagus nerve might be functioning flawlessly and still have you stuck in fight-or-flight because it TRULY. BELIEVES. YOU ARE. IN. DANGER.

Your vagus nerve itself is probably fine, honey. It might be society that's the problem. It might be your environment. It might be our stored memories, our earliest traumas and painful experiences, buried so deeply that we sometimes cannot access them, but that provide clear instructions for what constitutes a threat worthy of shutting down social engagement mode: abandonment wounds, insecurities, fear of loss, destitution, or being labelled other.

We have known about the vagus nerve for a long time, but the intricacies of its functioning and how it is linked to the rest of our body's functioning are still being investigated. Fortunately, there are many available techniques and interventions that you can apply without consulting a doctor about your vagus nerve. Activities such as yoga, meditation, and deep breathing can help activate the parasympathetic system, bringing balance to both systems and improving our overall well-being⁵.

By slowing down heart rate and breathing, we can activate our parasympathetic system and come back to a productive, non-activated mental and physical state⁶. The way I look at it, by choosing to take deep breaths when in an activated state, I'm communicating to my body that I am, in fact, safe.

Here are some activities you can try:

  1. Deep Breathing: Engage in slow, deep breaths, focusing on extending the exhale longer than the inhale. This helps activate the relaxation response and stimulates the vagus nerve.
  2. Meditation: Practice mindfulness meditation or other forms of meditation to calm the mind, reduce stress, and promote relaxation. Meditation activates the parasympathetic system and enhances vagal tone.
  3. Yoga: Participate in yoga sessions that incorporate gentle stretches, deep breathing, and mindfulness. Yoga combines physical movement, breath control, and meditation, all of which stimulate the vagus nerve and promote relaxation.
  4. Singing or Chanting: Singing, humming, or chanting can stimulate the vagus nerve and improve vagal tone. Engaging in activities that involve vocalization can have a calming effect on the body and mind.
  5. Cold Exposure: Brief exposure to cold water or cold showers can activate the vagus nerve and stimulate the parasympathetic system. Start with splashing cold water on your face or gradually expose yourself to cold temperatures.
  6. Laughter: Genuine laughter triggers the release of endorphins and activates the parasympathetic system. Engage in activities that make you laugh, such as watching funny videos or spending time with loved ones who bring joy.
  7. Massage or Self-Massage: Receive a gentle massage or practice self-massage techniques, particularly around the neck, throat, and chest area. Massaging these areas can stimulate the vagus nerve and promote relaxation.
  8. Socializing and Connection: Engage in meaningful social interactions with friends, family, or support groups. Positive social connections help activate the parasympathetic system and increase vagal tone.
  9. Mindful Eating: Slow down and savor your meals, paying attention to the flavors, textures, and sensations. Mindful eating promotes digestion and activates the vagus nerve's connection to the gastrointestinal system.
  10. Practicing Gratitude: Cultivate a regular gratitude practice by expressing appreciation for the positive aspects of your life. Gratitude activates the parasympathetic system and fosters a sense of well-being.

Ultimately, the vagus nerve is a crucial player in our body's ability to handle daily stress and maintain balance. So, next time you're feeling overwhelmed, take a moment to thank your vagus nerve and give it a little support through activities like yoga, meditation, and deep breathing. Your body (and mind) will thank you!

  1. Kanai, T., & Teratani, T. (2022). Role of the Vagus Nerve in the Gut-Brain Axis: Development and Maintenance of Gut Regulatory T Cells via the Liver-Brain-Gut Vago-Vagal Reflex. Brain and Nerve = Shinkei Kenkyu No Shinpo, 74(8), 971–977. https://doi.org/10.11477/mf.1416202163
  2. Porges, S. W. (2011). The polyvagal theory: Neurophysiological foundations of emotions, attachment, communication, and self-regulation (pp. xvii, 347). W W Norton & Co.
  3. Alshak, M. N., & M Das, J. (2022). Neuroanatomy, Sympathetic Nervous System. In StatPearls. StatPearls Publishing. http://www.ncbi.nlm.nih.gov/books/NBK542195/
  4. Marmerstein, J. T., McCallum, G. A. & Durand, D. M. (2021). Direct measurement of vagal tone in rats does not show correlation to HRV. Nature Scientific Reports. https://www.nature.com/articles/s41598-020-79808-8
  5. Sullivan, M. B., Erb, M., Schmalzl, L., Moonaz, S., Noggle Taylor, J., & Porges, S. W. (2018). Yoga Therapy and Polyvagal Theory: The Convergence of Traditional Wisdom and Contemporary Neuroscience for Self-Regulation and Resilience. Frontiers in Human Neuroscience, 12. https://www.frontiersin.org/articles/10.3389/fnhum.2018.00067
  6. Gerritsen, R. J. S., & Band, G. P. H. (2018). Breath of Life: The Respiratory Vagal Stimulation Model of Contemplative Activity. Frontiers in Human Neuroscience, 12, 397. https://doi.org/10.3389/fnhum.2018.00397

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