Historically cited as the pneumogastric nerve, modern day medics know the vagus nerve as the tenth cranial nerve, or CN X. The vagus nerves are generally referred to in the singular. It is made up of sensory and motor fibres and, as a single entity, it forms the longest nerve of the autonomic nervous system in the human body. The motor fibres come from neurons of the dorsal motor nucleus of the vagus and the nucleus ambiguous, whereas the sensory fibres originate from neurons of the nodose ganglion.

The vagus nerve forms an important component of the parasympathetic nervous system. It interfaces with the parasympathetic control of the heart, lungs, heart, gut and liver.

The vagus nerve’s roles in the human body include:

Enabling neurogenesis, helping your brains sprout new brain cells.
Rapidly switching off your stress, hyper-arousal, and fight/flight via the relaxation response.
Sharpening your memories.
Fighting inflammatory diseases.
Helping you to resist high blood pressure.
Blocking the hormone cortisol and other oxidizing agents that age and deteriorate your brain and body.
Blocking systemic inflammation- a major factor behind aging and poor health.
Helping your to overcome depression and anxiety.
Helping you to sleep better.
Raising levels of human growth hormone.
Helping you to overcome insulin resistance.
Turning down allergic responses.
Lowering your chances of suffering from stress and tension headaches.
Helping spare and grow your mitochondria- this is a key to maintaining optimal energy levels and not harming our DNA and RNA.
Affect your overall ability to live a longer, healthier, and more energetic life.
As you can see, the vagus nerve is therefore responsible for a wide range of tasks over a wide range of body mechanisms. Tasks such as heart rate regulation, gastrointestinal peristalsis, sweating, and quite a few muscle movements in the mouth, including speech and the gag reflex, are all affected by it. It also plays a role in satiation post food consumption.

However, of all of the above roles, it is the vagus nerve’s ability to impact upon concentration levels, focus and mental clarity that are perhaps the most interesting. We have seen that it promotes the construction of new brain cells. An active, healthy vagus nerve is therefore central to maintaining long-term cognitive health. Similarly, it helps the memory to function properly. It helps to fight depression and anxiety. It mitigates inflammation, which is intimately linked to depression and similar mental health concerns that are known to impinge upon mental focus and clarity, as well as to aging and physical decline. Its ability to block cortisol and other stress agents feeds into this. It allows for better sleep.

For these reasons and more, maintaining a healthy vagus nerve is central to maintaining cognitive health, on which mental clarity, concentration levels and focus are completely reliant.

With all of the above in mind, when we say that you can stimulate the vagus nerve and thus make it more efficient, we are talking about a potentially very profound phenomenon.

How to activate the vagus nerve for greater efficiency
The vagus nerve’s functioning can be impaired. This is known as having a ‘low vagal tone’ and is a well-known contributing factor to stress. It can often lead to conditions such as depression, anxiety, inflammation and muscular tension.

Luckily, this can be protected against or reversed. Regular stimulation to the vagus nerve can increase the vagal tone, thus relieving or eradicating many symptoms of stress.

Direct stimulation of the vagus nerve is only possible through medical intervention. A device can be implanted that emits electrical impulses that, in turn, stimulate the vagus nerve. However, as we have seen, the vagus nerve is deeply interconnected with a great many parts of the body.

Stimulating these parts of the body can indirectly, though effectively, bring about a positive influence on the vagal tone, improving the vagus nerve’s efficiency over time.

Vagus nerve stimulation can be achieved simply enough via a number of breathing and relaxation techniques, including:

Deep, slow belly breathing
Chanting
Cold water immersion, especially post-workout, especially facial immersion
Filling the mouth with saliva and submerging the tongue to trigger a hyper-relaxing vagal response
Loud gargling with water
Loud singing
Of the many methods available for doing this, exposure to cold is one of the most accessible and most efficient. Exposing your body to cold conditions, such as making use of cold water immersion therapy, taking a cold shower, or even simply splashing your face with cold water, or submerging your face in cold water, will increase stimulation of the vagus nerve. While your body adjusts to the cold, parasympathetic activity increases while sympathetic activity declines. The vagus nerve is, of course, a key component to the parasympathetic nervous system.

Cold water immersion and vagal nerve stimulation
Mitigating the effects of stress and enhancing concentration levels, focus and mental clarity are cornerstones of cold water immersion. During cold water immersion, participants submerge their bodies in cold water- either partially or completely. Water temperatures can be as low as 10 degrees C.

Cold face immersion, a form of cold water immersion, also works well for vagal nerve stimulation. Participants sit in front of a basin of cold water and bend their heads forward. The face will be immersed so that the forehead, eyes, and at least two-thirds of both cheeks are submerged. Water temperature will once again be as low as 10 degrees C. This will bring about a sufficient parasympathetic response to stimulate the vagal nerve.

Cold water immersion can be particularly effective in this regard when performed immediately post-exercise. Heightened levels of physical exertion can cause an increase in sympathetic activity (HPA axis – fight/flight, stress response), along with parasympathetic withdrawal (resting, digesting, healing, immune function). Cold water immersion is a remarkably simple and efficient way to immediately accelerating post-exercise parasympathetic reactivation via the vagus nerve. Heart rate reduction will be stimulated, as will motility through the intestines. Activation of several immune function metrics should be shown.

These will all happen alongside the long-term benefits to concentration levels and focus inherent to vagus nerve stimulation. Many of the body’s base functions- all of those, indeed, effected by the vagus nerve- will be improved by vagal nerve stimulation, particularly in the form of cold water immersion. This will lead to enhanced wellness and energy levels which, in turn, result in greater cognitive capacity and thus concentration levels in and of themselves.

Combined with the improved circulation, improved sleep, inhibited cortisol response, anti-inflammatory response, mitigation of depressive and anxiety related symptoms and improved neurogenesis inherent to vagal nerve stimulation, these effects will lead to long-term improvements in concentration, focus and mental clarity.