The vagus nerve, also known as the vagal nerves, because they are, in fact, two, and perhaps, the main nerves of the parasympathetic nervous system, or more specifically, it is the sensory network that informs the brain of what is going on in organs of our body such as the digestive tract (stomach and intestines), lungs, heart, spleen, liver and kidneys.
The vagal nerve or nerves are involved in everything from speech to eye contact, to facial expressions and even the ability to tune in to other people's voices. It has become especially important these days because it is responsible for calming your organs after the stressful "fight or flight" adrenaline response to danger.
You're probably already realising that the vagus nerve plays a vital role in general well-being. But guess what? It may also be behind chronic inflammation and pain.
When your vagus nerve is functioning at 100%, you have the ability to bounce back more quickly after a perceived shock or danger, whether it's encountering a tiger, or simply a perceived threat such as panic when speaking in public. If the vagus nerve has a low tone, i.e. is not functioning at 100%, you will find it difficult to regulate inflammation, which can trigger damage to organs and blood vessels, should the inflammation become chronic.
If you experience fatigue, anxiety, digestive problems, food sensitivities, depression, brain fog or a feeling of despondency, the vagus nerve might be involved and, of course, affected.
Anti-inflammatory Properties of the Vagus Nerve
In the body's autonomic nervous system, the communication between the brain and the internal organs, such as the heart and the intestines, is controlled. There, as mentioned above, the vagus nerve plays a crucial role in maintaining and/or restoring the body's balance.
Recent research has indicated that the vagus nerve has the ability to reduce inflammation in the body. This anti-inflammatory effect is achieved through different mechanisms, such as the release of cortisol to suppress inflammation. Because of the importance of the vagus nerve in the interactions between the brain and the digestive system, it is considered as a possible target for the treatment of diseases of the intestinal tract, such as inflammatory bowel disease and rheumatoid arthritis, among others.
One form of treatment is through neuromodulation using electronic devices, making it an alternative non-pharmacological therapy to conventional treatments, although more experiments are needed to consolidate its use.
Vagus Nerve as a Modulator of the Brain-Gut Axis in Psychiatric and Inflammatory Disorders
The vagus nerve constantly sends updated sensory information about the state of the body's organs "upstream" to your brain via afferent nerves (which carry information from the periphery to the Central Nervous System). In fact, 80 to 90 per cent of the nerve fibres of the vagus nerve are dedicated to communicating the state of the viscera to the brain by establishing one of the connections between the brain and the gastrointestinal tract where afferent fibres send updated information about organ status.
Preliminary evidence suggests that vagus nerve stimulation may be useful as an additional treatment for resistant depression, post-traumatic stress disorder and inflammatory bowel diseases. This type of treatment increases vagus nerve activity and reduces inflammation in the body, which can help improve resilience. By stimulating certain nerve fibres in the gut, areas of the brain that are important for regulating mood and anxiety may be affected.
Preliminary studies suggest that certain beneficial gut bacteria or probiotics may have positive effects on your mood and anxiety level by influencing the vagus nerve. The vagus nerve is linked to better stress management, and it has been observed that activities such as meditation and yoga can increase its activity, which may help improve your ability to cope with difficult situations and reduce symptoms of sadness and anxiety.
The best thing is that, as with any other part of the body, your vagus nerve can be strengthened or toned, making it work more efficiently. According to a study published in 2018, toning the vagus nerve increases the body's resilience, i.e. the ability to switch between stressful and calm states. Increased activation of the vagus nerve has also been shown to be anti-inflammatory, providing general wellbeing to the body.
However, it is not a one-day thing. Like any workout, it needs to be stimulated at least once a day, and the more you practice something, the easier it is for your brain to call on it in times of need. As you stimulate it, you will be creating new neural pathways that you can access in times of stress or anxiety.
Benefits of Stimulating Your Vagus Nerve
The vagus nerve can affect both your physical and mental health in a number of ways. Through vagus nerve stimulation, which can be done with an electrical device, but also non-invasively, you can keep it healthy and toned.
The benefits are reflected in:
- Treatment of epilepsy by minimising seizures
- Treatment of drug-resistant depression
- Emotion regulation
- Stress reduction
- Reducing blood pressure
- Reducing heart rate
- Reducing inflammation
- Treating migraine and cluster headaches
Your vagus nerve plays an important role in your body and to keep it strong and balanced you can play a part by giving your body some key nutrients and adopting certain practices to help you do this.
Foods that Help Tone up Your Vagus Nerve
Omega-3s. These are essential fats that your body cannot produce and must obtain from your diet or through supplements. Foods rich in omega-3s include cold-water fish such as mackerel, tuna and salmon, flaxseed, and chia seeds. These fats are necessary for the normal electrical functioning of the brain and nervous system. Studies show that omega-3 fatty acids increase vagal tone and vagal activity and therefore help to reduce heart rate and increase heart rate variability.
Cardiac variability: this refers to the time between heartbeats, a parameter that reflects the state of the heart's autonomic mechanisms.
On the other hand, both high-carbohydrate and high-fat diets will alter the vagus nerve's signalling of satiety. A report in the journal Nature, published an experiment on rats with obesity induced through these two types of diet, the results of which showed that both high-fat and high-carbohydrate diets impair the activity of the vagus nerve.
Probiotics. The nervous system of the gut connects to the brain via the vagus nerve, which has been described as "the interface of the microbiota-gut-brain axis".
In an animal study, mice supplemented with the probiotic Lactobacillus rhamnosus experienced several positive changes in GABA receptors mediated by the vagus nerve.
GABA receptors in the brain are involved in mood; a possible link between gut stimulation of the vagus nerve by L. rhamnosus and increased GABA activity adds to an emerging body of evidence on the potential health benefits of probiotics.
Consuming fibre. The hormone GLP-1 (Glucagon-like Peptide-1) is a hormone that stimulates impulses from the vagus nerve to the brain, slowing down bowel movements and making us feel more satiated after meals. (study)
Animal studies suggest that fibre may be a good way to increase GLP-1. GLP-1 is synthesised and secreted primarily by enteroendocrine L cells in the gastrointestinal tract. Its secretion is mediated in part by direct nutrient sensing via G protein-coupled receptors, which specifically bind monosaccharides, peptides and amino acids, monounsaturated and polyunsaturated fatty acids, as well as short-chain fatty acids.
Foods rich in these nutrients, such as fibre-rich products, nuts, avocados and eggs, also appear to influence GLP-1 secretion and therefore may promote associated beneficial outcomes in healthy individuals, as well as in individuals with type 2 diabetes or other metabolic disorders.
Practices that Allow You to Stimulate Vagus Nerve Function
Fasting. Both intermittent fasting and reduced caloric intake have been shown to increase heart rate variability in animals, which is thought to be an indicator of vagal tone.
According to one theory, the vagus nerve may mediate a reduction in metabolism during fasting. Specifically, the vagus nerve detects a decrease in blood glucose and a decrease in mechanical and chemical stimuli from the gut. This appears to increase vagal impulses from the liver to the brain (NTS), which slows the metabolic rate, according to animal data.
These animal studies suggest that hormones such as NPY (Neuropeptide Y) increase while CCK (Cholecystokinin) and CRH (Corticotropin-releasing hormone) decrease during fasting.
Immersion/exposure to cold (cold showers, going outside in cold temperatures with little clothing)
Due to the proximity of the vagus nerve to the skin in the neck and head region, the effectiveness of activating the nerve and the degree of treatment possible by non-invasive methods is being investigated.
According to an article in the journal www.icebarrel.com when the sympathetic nervous system is over-activated, the body experiences "fight or flight" stress. This causes physical stress, but also mental and emotional distress. Low heart rate variability (HRV) is a good indicator of depression and anxiety, as well as being associated with cardiovascular disease.
Non-invasive vagus nerve stimulation has been shown to improve HRV and reduce overall heart rate in athletic recovery, but it has also been found that this would apply to people with habitual daily stress (Buchheit et al., 2009; Jungmann et al., 2018). Cold water immersion is one of the best non-invasive vagus nerve stimulation methods for reducing daily stress, as well as recovery from exercise and improved general fitness.
Humming and Singing
The larynx is connected to the vagus nerve. When you sing, hum, or say "om", you are activating the nerve. If you are stressed or anxious you can try humming to calm down: you will probably notice that your heart rate slows down and you start to feel yourself relaxing.
As the vagus nerve is connected to the vocal cords and muscles in the back of the throat, singing, humming and even gargling would activate these muscles and stimulate the toning of the vagus nerve.
Meditation/mindfulness
As the vagus nerve is part of the parasympathetic system it is subject to your breathing rhythms, i.e. it can become agitated or calm depending on how you are breathing.
Meditation, in general, encourages you to become aware of your breathing and work with it to counteract circumstances that affect you from the outside and teaches you to reset your body to keep you stable and your mind clear in facing challenging situations.
Deep and Slow Breathing DSB
A study published in the journal Nature in 2021 states that breathing exercises appear to reduce anxiety and increase parasympathetic activity as assessed by HRV (heart rate variability) indices. The results of the study indicated that in both young and older adults who participated in the study, DSB significantly increased HF (high frequency) potency and reduced state anxiety.
This would reflect an increased benefit of vagal tone contributing to improved emotional regulation strategies with age or, possibly, a compensatory mechanism promoting effective anxiety management.
Indeed, neuro-visceral integration and the psychophysiological coherence model indicate that higher HRV (especially in the HF band) is associated with better cognitive performance. Higher vagal activity also predicts better emotion regulation strategies, such as the prevention of negativity but greater positivity effect in ageing.
Finally, taking a more clinical perspective, DSB would fit very well among the effective techniques offered as part of Acceptance and Commitment Therapy (ACT) to reduce anxiety, stress, or pain in older adults, among others.
Exercise
Studies show that exercising and getting the body moving can affect the vagus nerve. Interval training and cardiovascular endurance training can increase vagus nerve activity and improve heart rate variability.
Exercise reduces sympathetic nerve activity and modulates the parasympathetic response, so that cardiovascular and respiratory function are balanced.
Yoga
According to the magazine www.livescience.com "yoga helps regulate the parasympathetic nervous system by reducing resting heart rate, breathing patterns and allowing the body and mind to release the stresses of everyday life. For these reasons, yoga can help increase resistance to life's stressors and self-regulation, thereby increasing vagal tone."
Foot Massage or Reflexology
(gentle or firm touch that can contribute to nerve stimulation).
A study published in 2011 by the US National Library of Medicine indicates that foot reflexology can increase vagal modulation, decrease sympathetic stimulation and lower blood pressure in healthy subjects and patients with coronary artery disease.
When the vagus nerve is stimulated it triggers the release of oxytocin, and this hormone promotes relaxation, healthy digestion, and a general feeling of well-being.
When massage is applied to the feet, stimulating the vagus nerve, this in turn reaches and stimulates all the organs of the body promoting a feeling of well-being.
You can see how important the optimal health of your vagus nerve is. If it is out of balance, your physical and mental health can be at risk. That's why stimulating the vagus nerve can help enhance the efficient functioning of your entire body.