The Vagus Nerve: the Unsung Hero for Optimising Well-Being

Have you ever heard the saying, "Listen to your gut"? Well, it turns out there's a scientific basis for that advice, and it involves a little-known and fascinating component of our nervous system called the vagus nerve. The vagus nerve has been emerging as an unsung hero in recent years and has been quietly stirring up excitement amongst health practitioners, prompting a wave of "vagal toning" techniques across the well-being scene. So what's the big deal and should we all be paying more attention to this under appreciated part of our anatomies?

Our body is made up of a bustling network of trillions of nerves. These are electrical messengers, transmitting impulses which send signals between different parts of the body. These signals trigger motor reactions, such as muscle movement, or sensory responses, for example smell or taste. Tucked at the back of the brain are 12 pairs of nerves, known as cranial nerves, which transmit information between the brain and other parts of the body. The vagus nerve is the longest of these cranial nerves and originates in the brainstem. It is made up of a complex network of fibres that extends throughout the body, reaching many of our organs such as the heart, lungs, digestive system, and even the ears and tongue. Its name, derived from the Latin word for "wandering," reflects its meandering path as it traverses through the body, connecting each of these organs to the brain.

Why does the Vagus Nerve matter?

The vagus nerve is essentially the mastermind of our stress response, through its role in regulating our autonomic nervous system (ANS), the part of our nervous system which governs our unconscious bodily processes, including breathing, heart rate, digestion, and certain reflex actions, such as swallowing, coughing and sneezing. It accomplishes this by facilitating communication and balance between the two branches of our ANS: the sympathetic nervous system, responsible for triggering the "fight or flight" response during stressful situations, and the parasympathetic "rest and digest" state which is the relaxed, recovery state we should be in the majority of the time (although in practice, this is often not the case).

In this way, the vagus nerve is intimately linked to the body's stress response system, controlling how quickly our bodies shift back into the parasympathetic rest and digest mode after experiencing a stressful situation. Since the ability to modulate stress levels is crucial for maintaining balance and resilience in the face of life's challenges, a healthy vagus nerve is critical to our overall well-being.

Why is a parasympathetic state so important?

When our body is in a sympathetic fight or flight state, it kicks into survival mode, focusing all its energy on priming our physiology to address the perceived threat, such as to escape a physical predator. It does this by widening the lung airways to increase oxygen intake, increasing heart rate to improve oxygen delivery to muscles and vital organs, enlarging pupils to improve vision and releasing glucose from temporary stores to generate immediate energy. In doing so, the body diverts energy away from activities it considers to be less urgent such as digestion, immune regulation and production of reproductive hormones. While these changes are not an issue for a temporary period, when stress becomes chronic and ongoing, the health implications of these physiological changes become problematic. These can lead to a multitude of health issues, including inflammation, digestive problems, anxiety, depression, insomnia, diabetes, high blood pressure and cardiovascular disease.

Most of us are familiar with the concept of tone in relation to our muscles but when it comes to our nerves, tone represents their resilience and ability to signal clearly, quickly and efficiently. If our vagal tone is low, the vagus nerve doesn't signal as well as it should which means we shift very quickly into our sympathetic state and our ability to switch back into a parasympathetic recovery state is compromised, leaving us in a stress state more of the time. Improving our vagal tone allows us to become more resilient and better able to balance out the stress response.

Heart rate variability (HRV), the fluctuation in the time between each heartbeat, is considered a key indicator of vagal tone. Since many wearables now track HRV, this is a useful way to monitor in vagal tone. It's therefore no coincidence that many of the activities promoted to increase HRV also improve vagal tone.

So how can we improve vagal tone?

1. Breathing & Meditation: slow nasal breathing exercises are a powerful tool for improving vagal tone. At the simplest level, a breathing approach where you maintain your exhale for longer than your inhale will decrease your heart rate and increase parasympathetic activity and vagal tone. Similarly, resonance breathing has been shown to be particularly effective in increasing HRV and vagal tone. Meditation practices are also beneficial as they focus on slow and calm breaths.

Nasal breathing is key here. This is because when we breathe through our noses, the diaphragm moves down and up with every in and out breath, causing changes in pressure in the abdominal region. This in turn results in movement of our organs, effectively generating a gentle massage effect. The nerve fibres surrounding these organs, including those of the vagus nerve, are also activated by this movement. In this way, nasal breathing plays a fundamental role in vagus nerve stimulation. So another good reason to take some time in your day to introduce breathwork practices.

2. Cold Exposure: cold therapy has been shown to increase both HRV and parasympathetic activity, consequently also positively influencing vagal tone. You can start by introducing 30 seconds of cold water at the end of your shower, and build this up, or if you're feeling brave, try some biohacking activities such as cold water immersion or cryotherapy!

3. Move Your Body: moderate to high intensity physical activity has been shown to stimulate vagus nerve activation. More generally, even light exercise, for example walking or yoga, can have a positive impact on HRV.

4. Connect Socially: increases in positive emotions and social connectedness are associated with higher vagal tone, so this is a great excuse to strengthen your social bonds and nurture your relationships. Whether it's a heartfelt conversation over coffee or a virtual hangout with loved ones, social connection is fantastic way to look after your vagus nerve.

5. Singing, Humming, Chanting and Gargling: because the branches of the vagus nerve pass through the muscles at the back of the throat as well as the ear canals, the vibration generated by activities such as singing, humming and loud gargling with water activate these branches and in turn are thought to stimulate the vagus nerve. These practices might not necessarily be appreciated by everyone else in your household but at least your vagus nerve will thank you for them!

6. Massage: massaging areas of the body near the vagus nerve, such as the back of the neck and the carotid artery (located at the sides of the neck where it meets the jaw) has been shown to increase HRV and vagal tone.

The Sensate is an infrasonic resonance device that effectively reproduces the effects of some of the vagal toning practices above, in part by replicating the vibrational impacts in the chest. It was developed by Stefan Chmelik, an integrated healthcare physician who has focused on the treatment of stress, anxiety, trauma and complex disease over a 30-year career. Chmelik created the Sensate as an alternate mechanism for nervous system regulation after finding that his clients were increasingly struggling to apply meditation and breathwork techniques. The pebble-shaped appliance is placed on the chest and works by emitting infrasonic frequency vibrations, which are combined with specially engineered soundscapes (selected through an app and played through headphones) to generate a calming effect on the nervous system. This is achieved through the low frequency vibrations being conducted through the chest bone into the thoracic cavity, which acts like a speaker, creating sound resonance and signalling the vagus nerve to relax. In this way the Sensate claims to increase vagal tone and to calm the brain, reducing stress and anxiety.

Does it deliver on this? It’s certainly showing promise when it comes to sleep benefits. In a Sensate-run pilot study of 25 participants using the device every day for 14 days, 22 participants reported feeling more relaxed at the end of the two weeks, with the average time to fall asleep decreasing significantly - from 63 minutes at the start of the study, to less than half of that, 25 minutes, by the end of the study. On average, participants also increased their overall sleep per night from 5.89 hours to 7 hours.