The wandering nerve, or vagus nerve, is the longest and most complex of the twelve pairs of cranial nerves that affect brain function. The vagus nerve is the main component of the parasympathetic nervous system, which oversees a wide range of key bodily functions: it controls mood, immune responses, digestion and heart rate.
🎓 Did you know? The vagus nerve forms an essential connection between the brain and the gastrointestinal tract and, through afferent fibres, sends information about the state of the internal organs to the brain.
Experts from Cleveland University described the vagus nerve in Forbes magazine as follows:
- It represents a superpower of the human body, as it suppresses or, conversely, triggers the stress response known as ‘fight or flight’.
- It is a way to develop a healthy stress response and become resilient to extreme discomfort.
- When the vagus nerve is stimulated, you feel calmer, more compassionate and warmer.
- Stimulating the vagus nerve benefits the autonomic nervous system and mental health.
- A healthy vagal tone means a stronger connection with your emotions as well as better physical health.
In short, when you have a healthy vagus nerve, you are more resilient and can get over trauma and problems. Extreme irritation of the nerve leads to emotional outbursts and severe signs of stress.
Table of contents
The vagus nerve, what is it and why is it so important for life?
The vagus nerve is the longest cranial nerve in the human body. Its name comes from the Latin word vagus, meaning ‘wandering’. This is because it wanders throughout the body, with a wide distribution connecting the brainstem to the body. Only mammals have this nerve.
🗣️ Doctors add: It helps the immune system, for example with the inflammatory response to illness.
It has four main functions:
- sensory,
- special sensory,
- motor and
- parasympathetic.
💡 Tip: A properly functioning vagus nerve supports positive thinking.
Irreplaceable functions that keep the body alive
When we talk about signals sent from the brain to other organs, we need to consider the four functions already mentioned:
- Sensory functions relate to the throat, heart, lungs and abdomen.
- Special sensory functions provide the sense of taste at the back of the tongue.
- Motor signals control movement in the throat muscles responsible for swallowing and speech.
- The parasympathetic system is responsible for the activity of the digestive tract (stomach and intestines), breathing and heart rate.
The functions of the vagus nerve can be further divided into seven categories. One of the most important is balancing the nervous system. The cranial nerves are influenced by the sympathetic and parasympathetic systems.
- The sympathetic system increases alertness, energy, blood pressure, heart rate and breathing rate.
- The parasympathetic system, in which the vagus nerve is heavily involved, reduces alertness, blood pressure and heart rate and helps with calming down, relaxation and digestion. It soothes the nerves.
🎓 Did you know? As a result, the vagus nerve also helps with defecation, urination and sexual arousal.
Other effects, just as important, if not more so
Other effects of the vagus nerve include:
- Communication between the brain and the gut: The vagus nerve carries information from the gut to the brain.
- Relaxation with deep breathing: The vagus nerve communicates with the diaphragm. When taking deep breaths, a person feels more relaxed and gets into a state of flow.
- Reducing inflammation: The vagus nerve sends an anti-inflammatory signal to other parts of the body.
- Lowering heart rate and blood pressure: If the vagus nerve is overactive, the heart cannot pump enough blood around the body. In some cases, excessive stimulation of the vagus nerve can cause loss of consciousness and organ damage.
- Managing fear: The vagus nerve sends information from the gut to the brain, which is linked to stress, anxiety and fear. This is where the English expression ‘gut feeling’ comes from. These signals help a person recover from stressful and frightening situations.
It consists of a dorsal (front) and a ventral (back) part, and each stimulus activates a different part. Safe (pleasant) signals activate the ventral part, while dangerous (life-threatening) signals activate the dorsal part.
💡 Tip: With brain training, you can stimulate the vagus nerve to a limited extent. Just 5 minutes of exercises a day is enough.
How to stimulate the vagus nerve
Vagus nerve stimulation is a medical procedure used to treat various adverse conditions. It can be done either manually or with electrical impulses.
🎓 Did you know? The effectiveness of vagus nerve stimulation has been confirmed by clinical studies. As a result, the US Food and Drug Administration (FDA) has approved its use for treating various conditions.
Epilepsy
In 1997, the FDA approved the use of vagus nerve stimulation for refractory epilepsy. It is based on a small electrical device similar to a pacemaker, which is placed in the chest. A thin wire known as a ‘lead’ runs from the device to the vagus nerve.
🗣️ Doctors add: The device is implanted surgically under general anaesthesia. It then sends electrical impulses at regular intervals throughout the day to the brain via the vagus nerve to reduce the severity of epileptic seizures or even stop them.
Side effects of vagus nerve stimulation in this case include:
- hoarseness or voice changes,
- sore throat,
- shortness of breath,
- cough,
- slow heartbeat,
- difficulty swallowing,
- stomach upset.
People receiving this form of treatment should tell their doctor if they have any problems, because excessive stimulation of the vagus nerve could worsen epilepsy symptoms.
Mental illness
In 2005, the FDA approved the use of vagus nerve stimulation to treat depression. It has been confirmed to help much more than, for example, homeopathic remedies for calming the nerves or natural antidepressants. It has been found to bring relief in the following disorders:
- bipolar disorder,
- anxiety disorder,
- Alzheimer’s disease.
How does vagus nerve stimulation work?
Interestingly, scientists still do not know exactly how vagus nerve stimulation works, or whether it is a brand-new phenomenon or an acquired habit.
However, they believe it helps control (epileptic) seizures by:
- improving blood flow to critical areas of the brain.
- overriding the chaotic electrical pattern that occurs during a seizure.
- increasing levels of neurotransmitters in the brain (specifically norepinephrine and serotonin) that govern the development of seizures.
It helps with managing depression by:
- changing the levels of specific neurotransmitters in the brain that play a role in regulating mood.
And it helps with rehabilitation after a stroke by:
- Stimulating the area of the motor cortex in the brain that controls the ability to move the arms and hands.
When is vagus nerve stimulation not a good option for you?
It may turn out that you are not a suitable candidate for vagus nerve stimulation, especially if:
- You are pregnant.
- You suffer from breathing problems, such as asthma, sleep apnoea, chronic obstructive pulmonary disease or another respiratory disorder.
- You have an active peptic ulcer.
- You have insulin-dependent diabetes mellitus.
- You have only one vagus nerve left.
- You have dysautonomia, an abnormal functioning of the autonomic nervous system.
- You are already receiving other forms of brain stimulation.
- You have a heart arrhythmia or other heart abnormalities.
- You have a history of schizophrenia, schizoaffective disorder, delusions or bipolar disorder.
It is therefore essential to discuss every step carefully with your doctor.
