The Vagus nerve and its impact on anxiety and depression

The vagus nerve represents the main component of the parasympathetic nervous system, which oversees a vast array of crucial bodily functions, including control of mood, immune response, digestion, and heart rate. It establishes one of the connections between the brain and the gastrointestinal tract and sends information about the state of the inner organs to the brain via afferent fibers. Treatments that target the vagus nerve increase the vagal tone and inhibit cytokine production. Both are important mechanism of resiliency. The stimulation of vagal afferent fibers in the gut influences monoaminergic brain systems in the brain stem that play crucial roles in major psychiatric conditions, such as mood and anxiety disorders. There is also preliminary evidence for gut bacteria to have beneficial effect on mood and anxiety, partly by affecting the activity of the vagus nerve. Since, the vagal tone is correlated with capacity to regulate stress responses and can be influenced by breathing, its increase through meditation and yoga likely contribute to resilience and the relief of mood and anxiety symptoms.

Alongside the sympathetic nervous system and the enteric nervous system (ENS), the parasympathetic nervous system represents one of the three branches of the autonomic nervous system.

The definition of the sympathetic and parasympathetic nervous systems is primarily anatomical. The vagus nerve is the main contributor of the parasympathetic nervous system. Other three parasympathetic cranial nerves are the nervus oculomotorius, the nervus facialis, and the nervus glossopharyngeus.

IMAGE: https://www.britannica.com/science/human-nervous-system/The-autonomic-nervous-system

The most important function of the vagus nerve is afferent, bringing information of the inner organs, such as gut, liver, heart, and lungs to the brain. This suggests that the inner organs are major sources of sensory information to the brain. With the gut being the largest surface toward the outer world one would think that it would be a particularly important sensory organ.

Anxiety can be impossibly complicated, deeply personal, and really hard to predict. There are times when we think our anxiety is behind us but then something can shift and we are fighting to get back to a place of peace and calm. We are all students of our anxiety and that’s why understanding exactly how our nervous system works and how we can calm it, can be incredibly beneficial and empowering.

We would think that calming the nervous system is slowing the heart rate, expanding the breath, and relaxing various muscles, but what actually connects these sensations to the brain is the vagus nerve. This part of the body seems to explain how our minds control our bodies and how our bodies influence our minds. Through this understanding we might get the tools we need to calm and regulate them both.

In Latin the word ‘vagus’ means wandering.  The vagus nerve, cranial nerve V is the longest cranial nerve and ‘wanders’ throughout the body linking many of the organs to the brain.  Originating from the brainstem it travels down the neck, through the ears, connecting to all the organs in the chest, abdomen and gut, to then flow back up again to the brain allowing relevant information to be provided.  The body then responds as needed including decreasing inflammation, stimulating gut motility, producing digestive enzymes, reducing the heart rate and lowering blood pressure.

There are two sides to this vagus nerve, the dorsal (back) and the ventral (front). From there, the two sides of the vagus nerve run down throughout our body, considered to have the widest distribution of all the nerves within the human body.

Image: https://www.frontiersin.org/articles/10.3389/fpsyt.2018.00044/full

It is intuitive for us to scan our environment for cues of safety and danger. In polyvagal theory, Dr. Porges describes the process in which our neural circuits are reading cues of danger in our environment as neuroception. Through this process of neuroception, we are experiencing the world in a way in which we are involuntarily scanning situations and people to determine if they are safe or dangerous. As part of our autonomic nervous system, this process is happening without us even being aware that it is happening. In the process of neuroception, both sides of our vagus nerve can be stimulated. Each side (ventral and dorsal) has been found to respond in clear and independent ways as we scan and process information from our environment and social interactions.

The ventral vagus nerve responds to cues of safety in our environment and interactions. It supports feelings of physical safety and being safely emotionally connected to others in our social environment. The dorsal vagus nerve responds to cues of danger. It pulls us away from connection, out of awareness, and into a state of self-protection. In moments when we might experience a cue of extreme danger, we can shut down and feel frozen, an indication that our dorsal vagal nerve has taken over.

Within his polyvagal theory, Porges describes that there are three evolutionary stages involved in the development of our autonomic nervous system. Rather than simply suggesting that there is a balance between our sympathetic and parasympathetic nervous system, Porges describes that there is actually a hierarchy of responses built into our autonomic nervous system.

Immobilization. Involving an immobilization response is described as the oldest pathway. The dorsal vagus nerve responds to cues of extreme danger, causing us to become immobile. This means that we would respond to our fear by becoming numb and shutting down. It is almost as if our parasympathetic nervous system is firing on all cylinders and our response actually results in us freezing instead of simply slowing down.

Mobilization. This is a sympathetic nervous system response. This helps us mobilize when faced with danger. We receive an adrenaline rush to get away from danger or to fight off our threat. The polyvagal theory suggests that this pathway was next to develop in the evolutionary hierarchy.

Social engagement. This is the newest addition to the hierarchy of responses, and is based in the ventral vagus nerve. This part of the vagus nerve responds to feelings of safety and connection. Social engagement allows us to feel grounded and secure and is facilitated by the ventral vagus pathway.

In life there will always be moments that we feel safe and secure, and others that we perceive threat and danger. The polyvagal theory suggests that this is all fluid – moving in and out of different safety zones within the hierarchy of responses.

In a day we could experience a range of activations from experiencing social engagement in the embrace of a loved one to feeling a sense of immobilization as we are confronted with danger.

Our social engagement allows us to interact more dynamically with others, feeling connected and safe. When our body picks up a cue within an interaction that signals we may no longer be, it begins to respond. For many, this stimulus may move them into a place of a mobilization response, springing into action to attempt to neutralize the threat or get away from it.

Although the vagus nerve is known for being widely distributed and connected to a variety of areas of the body, this system can influence cranial nerves that regulate social engagement through facial expression and vocalization. We innately long for feelings of safety, trust, and comfort in our connections with others and quickly pick up cues that tell us when we may not be safe. As people become safer with and for each other, it can be easier to build healthy bonds, share vulnerabilities, and experience intimacy with each other.

Low vagal tone can result in conditions such as:

  • IBS
  • Anxiety
  • Depression
  • Addictive Behaviour
  • Diabetes
  • Heart Disease
  • Endometriosis
  • Chronic Fatigue Syndrome
  • Autoimmune diseases
  • Alzheimer’s
  • Tinnitus
  • Migraines
  • Cancer

How is the vagus nerve influencing my health?

In 1921, a German physiologist first discovered that stimulating the vagus nerve caused the heart rate to slow down by triggering the release of a substance he called Vagusstoff (vagus substance). It was later discovered that this substance was actually acetylcholine which is an important neurotransmitter in our nervous system. Since then, researchers have discovered a lot more about the vagus nerve and the role it plays in quite a few different diseases and important systems in the body. For example, electrical stimulation of this nerve has been shown to reduce the rate of epileptic seizures and help with depressive symptoms. Vagal tone, the strength of ones vagus nerve, can be connected to inflammationimmune system regulationmetabolism, and emotional regulation.

Low vagal tone is associated with poor emotional and attentional regulation, inflammation, depression, and is even used as a measurement for a person’s sensitivity to stress. Meanwhile, a healthy vagal tone is associated with positive emotions and psychological balance. Some studies have even shown that increasing vagal tone could help to treat addiction and certain cravings.

There are some everyday (fun) practices which, when done regularly, can be effective in developing good vagal tone, improve mood and develop a stronger resilience to stress.

We all want to feel a sense of empowerment by being able to take our health (current and future) into our own hands.

Christopher Bergland in Psychology Today wrote that “Vagusstoff (acetylcholine) is like a tranquilizer that you can self-administer simply by taking slow, deep diaphragmatic breaths.” So it seems as though the vagus nerve has a lot to do with breathing, which leaves no wonder that yoga and meditation focus so much on this principle. Besides breathing, there are lots of different ways to give your vagus nerve a much-needed workout.

Here are 8 vagus nerve “work-outs” that will help you fight anxiety and stress on a neurobiological level:

Singing and music

Research shows that singing has a biologically soothing effect, which has a lot to do with the vagus nerve. This can be anything from chanting to cooking your favourite meal while singing your favourite ’90s song.

Laughter

We should always try to lighten the load and not take life too seriously, find ways to play, have fun and giggle because it feels great and by doing this, we are toning the vagal nerve, which improves our health and happiness. Win, Win.

Intermittent fasting

Some studies suggest that fasting and dietary restriction can activate the vagus nerve, and considering all the other health benefits of fasting, it’s definitely something to think about.

Reflexology

With the feet having over 7000 nerve endings, a Reflexology treatment is a fantastic way to access the nervous system to stimulate and strengthen the vagus nerve.  Offering a sense of calm and relieving pain it can support the body in functioning in a more optimum way.  Working the vagus nerve points during a treatment feels incredibly soothing and leaves us really relaxed and connected.

Cold exposure

Studies show that cold exposure causes a shift toward parasympathetic nervous system activity, which as we know is modulated by the vagus nerve. So if you’ve never explored the benefits of hot to cold showering, your vagus nerve could be a good reason to start.

Probiotics

The vagus nerve plays a major role in the gut-brain axis, and thanks to science, we now know that gut microorganisms can actually activate the vagus nerve. So investing in a good probiotic and investing in your gut health can play a major role in our brain and behaviour.

Taking some deep abdominal breaths

Vagal tone is measured by the difference between the heart rate when we inhale compared to the heart rate when we exhale.  Taking some long deep belly breaths is a fabulous way to activate the vagus nerve and give ourselves an internal loving hug.

Yoga Asana & Meditation

When we gift ourselves some time in the day for a focused mindfulness practice this gives us an opportunity to check in and connect with what we need, what we can let go of and follow what feels authentic. Being in a more congruent space will bring more personal happiness.

“Our gut instincts are not fantasies but real nervous signals that guide much of our lives.”

Dr. Mark Sircus, acupuncturist, and doctor of Oriental and pastoral medicine.

Case study: 

“On 21 December 2020 I was diagnosed with Stage 1 Lobular Breast Cancer. I was side swiped as I thought I was one of the healthiest people I knew. I am a Therapeutic Reflexologist and Yoga Instructor, I eat well, sleep well and don’t drink much (if any) alcohol. I have a daily yoga practice and aim to include meditation or mindfulness. There is no family history of breast cancer either, so truly it was the last diagnoses I was expecting. The following day my dad collapsed and went into a complete cognitive and physical shutdown. Within a week he had passed away of Covid-19. While he was dying, I was being tested, having scans and many doctors’ meetings planning how I was going to tackle my cancer. My beloved 13 year old golden retriever also had cancer and her palliative care was no longer supporting her. My life was moving into a completely new phase and one that was somewhat out of my control.

I know a lot of people that face a health challenge by researching all the possible outcomes and get caught up in the story of their illness or circumstances. I was trying not to do this. I wanted to stay very present and be with my pain, grief and loss. I needed to be practical with my treatment plan, as well as my father’s passing away and the logistics around packing up his home and wrapping up his estate. Alongside this, I needed to be there for Cayla while she was coming to the end of her life. It was a lot. It felt pretty overwhelming.

I decided to take this on in a very sober way, cutting out all alcohol and as much as possible my sugar and stimulant intake. I looked at my diet and consulted with a dietician to formulate a nutritious and supportive meal plan. I have naturally found that fasting serves my body and activity and stuck with my 16:8 breakdown. I saw my homeopath for a remedy to help support me holistically, and she also tested my nutritional balances and made sure I was on the right supplements. I made sure to sit in my Vacuflex Concepts boots as often as I could as I believe strongly in the healing power of reflexology.

I continued with my yoga practice and increased my meditation, yoga nidra, breathing exercises and vagal nerve toning exercises. I found it do be hugely cathartic to regulate my nervous system, to calm my thoughts and my racing heartbeat. I naturally leaned towards a slower way of being which felt more nurturing. I focused on being present and enjoying time with my daughter, mother and dogs pre-surgery.

I had my operation 3 weeks after my diagnosis and was in hospital for 7 nights which truly tested me. I had to dig deep and found that guided meditation as well as a mindful movement practice was key to keeping an even temperament. My nervous system was in a state of flux and needed constant regulation. The movement was interesting as it had to be modified to accommodate the restrictions of the breast surgery, so I learnt a lot about how I could move the anesthetic out of my system and get my bowel movements to work, while moving safely so not to compromise the stitches and drains.

When I came out of hospital I focused on my recovery and finding solutions to my future approach to life decisions and how I would self-regulate more efficiently. I added in a weekly session with an embodiment life coach, who has been helping me exponentially. We are working on tangible mindfulness practices and Dr Stephen Porges vagal nerve exercises designed to assist in congruence and expanding one’s window of tolerance (ultimately getting triggered less by stressors). It is a helpful approach to keep me in check physically and mentally.

Understanding how I got cancer is something I am working through. I have had genetic testing which highlighted a defected gene called Chek2, which increases my propensity to breast cancer. Something obviously triggered a response for the cancer to grow and as time goes by I am understanding this more.

My treatment is on-going, but thankfully I don’t need radiation or chemotherapy. I am on a chronic medication which allows for an excellent life expectancy prognosis incase a couple cancer cells escaped! I am working with a team of experts to help guide me through the process, but more than that, I am checking in with myself and ensuring my health needs are met and I am looking after ME. Healthy eating, exercise, lots of rest, good sleep, meditation, yoga, embodiment therapy, massage, reflexology, reiki….and I love to add to this list learn along the way.”

In conclusion:

Image: https://www.thecut.com/2019/05/i-now-suspect-the-vagus-nerve-is-the-key-to-well-being.html

The interaction between the gut and the brain is based on a complex system that includes not only neural but also endocrine, immune, and humoral links.

The vagus nerve is an essential part of the brain–gut axis and plays an important role in the modulation of inflammation, the maintenance of intestinal homeostasis, and the regulation of food intake and energy homeostasis. An interaction between nutrition and the vagus nerve is well known, and vagal tone can influence this and weight gain.

Professor of psychiatry Stephen Porges hypothesizes that the parasympathetic nervous system has two parts that cause two different responses: the dorsal vagal nerve network and the ventral vagal nerve network. When you can’t resolve a threat through fight-or-flight or establish a social connection to help calm you, your body sometimes decides it’s better to physically and mentally “check out.” or dissociate, and it’s the work of the dorsal vagal nerve network. When you’re dissociated, you’ll feel fatigued and hopeless, possibly depressed or anxious.

On the other hand, the ventral vagal nerve network gets activated when you’re connecting with another person, or even with yourself, by responding to your body’s signs of stress! This triggers calmness. The bottom line is that this s the part of your nervous system you want to stimulate when you’re stressed or anxious.

The vagus nerve plays an important role in the pathogenesis of psychiatric disorders, anxiety, depression as well as other stress-induced and inflammatory diseases.

The good news is that research on the Vagus Nerve, shows how people can tune in to their nervous systems and find ways back to a “rest and digest” state amidst the chronic stress. With more understanding of our neurological and physical constitutions, we can find an individual and achievable plan of action to regulate our nervous systems. Allopathic and complementary medicine can work in harmony while including mind and body practices that support this.

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Audiobook – The Pocket Guide to the Polyvagal System, Stephen W. Porges (Date accessed December 2020)

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