The vagus nerve is the longest nerve in the body. It connects your brain to many important organs including the stomach, intestines, liver, gallbladder, heart and lungs. It’s involved in controlling the immune, endocrine, respiratory and cardiovascular systems.
The vagus nerve plays an important role in activating parasympathetic tone (calming, rest, digest and repair branch) of the nervous system and turning off the stress, hyper-aroused, fight and flight sympathetic response. During conditions of rest, the parasympathetic nervous system facilitates digestion, bodily repair, and energy conservation.
As a major nerve of the parasympathetic system, the vagus nerve reflects your body’s ability to regulate inflammation, glucose, gut physiology, and heart rate.
The vagus nerve is a key player in the mind-body connection and the way that your heart responds to emotions, gut instinct, and intuition.
It’s also one of the mechanisms by which the stomach and intestines are affected by stress, and functions as the main link between the GI tract and the brain in a relationship known as the brain-gut axis.
The vagus nerve provides a direct mainline pathway from your brain to your gut.
Vagal tone reflects the level of parasympathetic activity and your body’s ability to successfully respond to stress, adverse life events, and environmental conditions.
Low vagal tone is associated with poor emotional and attentional regulation in children and has been conceptualized as a marker of sensitivity to stress in children, adolescents and adults. [J Clin Child Adolesc Psychol.]
Poor vagal tone has been associated with child psychopathology, and anxiety and depression in adults.
Several studies have shown that vagal tone is passed on from mother to child. Mothers who experience anxiety, depression and anger during their pregnancy have lower vagal activity. Once they give birth to their child, the newborn baby also has low vagal tone, and low dopamine and serotonin levels. [Depress Anxiety. 2003 and J Obstet Gynaecol. 2002]
“Decreased vagal function and heart rate variability were shown to be associated with increased fasting glucose and HgA1c levels, increased overnight urinary cortisol, and increased pro-inflammatory cytokines and acute phase proteins.” – Annals of the New York Academy of Sciences. Thayer, J.F. & Steinberg, E., 2006
High vagal tone is linked to an increased resilience to stress, reduced allostatic load (the amount of stress we accumulate over time), and healthier emotional, physical and psychological well-being.
People with higher vagal tone have healthier hearts, less inflammation, stronger social bonds, ability to feel calm and peaceful, and tend to exhibit better emotion regulation. [Biological Psychiatry]
Researchers have found a positive connection between high vagal tone, positive thoughts and emotions, and better physical health. The higher and stronger your vagal tone, the more your physical and mental health will improve, and vice versa. [Psychological Science]
People with high vagal tone are not just healthier, they’re also socially and psychologically stronger – better able to concentrate and remember things, happier and less likely to be depressed, more empathetic and more likely to have close friendships.
Any kind of GI distress can put pressure on the nerve and irritate it, with a hiatal hernia being a frequent culprit. Chronic stress and anxiety can inflame the nerve. If you’ve had braces or an extensive amount of dental work, you’re at risk for low vagal tone. Even something as simple as poor posture and muscular imbalances can cause the vagus nerve to misfire.
Damage to the vagus nerve can be caused by diabetes, excess alcohol, Rx, OTC and recreational drug use, upper respiratory viral infections, botox injections, heavy metal toxicity, or having part of the nerve severed accidentally during surgery or an operation.
Activation of the vagus nerve influences the stress response, mood, immune function, digestion, and heart rate. Stimulating the vagus nerve has a calming influence on the heart and lungs and calms down the body’s hypothalamus-pituitary-adrenal axis, turning off the stress response.
Strengthening the vagus nerve and increasing vagal tone has been shown to improve many brain conditions and health conditions including:
Think of vagus nerve stimulation as a kind of mental hygiene that requires consistency and regular practice to be most effective.
Cold therapy how-to: Submerge your body up to your shoulders in a large full immersion tub with ice and water, a cold swimming pool or a cold ice water bath. Splash cold water on your face. Apply a cold washcloth to the face. Go outdoors in cold weather wearing minimal clothing such as shorts and a tank top. End your shower with 60 seconds of cold water.