The vagus nerve is the longest nerve in your body. It connects your brain to many important organs throughout the body, including the gut, heart and lungs.
In fact, the word "vagus" means “wanderer” in Latin, which accurately represents how the nerve wanders all over the body and reaches various organs.
The vagus nerve is also a key part of your parasympathetic “rest and digest” nervous system. It influences your breathing, digestion and heart rate (all of which has a huge impact on your mental health).
The key thing here is the "tone" of your vagus nerve. Increasing your vagal tone activates the parasympathetic nervous system, and having higher vagal tone means that your body can relax faster after stress.
In 2010, researchers discovered a positive feedback loop between high vagal tone, positive emotions, and good physical health. In other words, the more you increase your vagal tone, the more your physical and mental health will improve, and vice versa.
Vagal tone is passed on from mother to child. Mothers who are depressed, anxious and angry during their pregnancy have lower vagal activity. And their newborn also has low vagal tone and low dopamine and serotonin levels.
And your vagal tone can be measured! It correlates directly with your heart rate, breathing rate and heart rate variability (HRV). Measured and therefore - optimised, by stimulation.
Conditions that have clinically been proven to benefit from vagal stimulation are a long list that includes things like MS, Autism, personality disorders, depression, fibromyalgia, tinnitus, chronic fatigue, brain injury, poor memory, etc etc.
So how do you stimulate the vagus nerve? Attention those on their Spiritual practice path, some of these will definitely give you an 'a-ha!' moment!

- Cold showers (or at least the last 30-60 sec)
- Deep and slow breathing (try going from 10-14 breaths per minute to 6 and really using your diaphragm) and meditation

- Singing, humming, chanting and gargling (the vagus nerve is connected to your vocal chords and the muscles at the back of your throat)
- Acupuncture, especially the ear type

-  Yoga and Tai-Chi (both increase the GABA neurotransmitter production precisely through stimulating the vagal tone)
-  Take a good Probiotics with varied strains and of clinical strength (min 25 bln), the good bacteria of your gut is connected to your brain through the vagus nerve
-  Eat a diet high in good fats, especially - the Omega 3s!
-  Exercise

-  Supplement with Zinc (picolinate)
- Massage (foot, reflexology, etc)
- Socialise and laugh (increases heart-rate variability, HRV)
- Intermittent fasting (periodically taking all your daily meals in an 8-hour window, which can be done either by skipping breakfast or eating an early dinner around 6 pm and then fasting until next breakfast), again - increases HRV