What Does the Vagus Nerve Do?

The vagus nerve is the longest and most complex of the 12 cranial nerves. Also called cranial nerve X or the 10th cranial nerve, it connects the brainstem to the body and transfers data between the surface of the brain and other body tissues and organs.

The vagus nerve supports the parasympathetic and sympathetic portions of the autonomic nervous system. The nerve transmits motor information for movement throughout the body and some sensory processes.

In essence, it is a component of a circuit that connects the brain to the neck, heart, lungs, and abdomen.

The vagus nerve is part of the neurological system and has critical functions in involuntary sensory and motor (movement) processes, such as:

• Digestion
• Heart rate
• Blood pressure
• Respiration (breathing)
• Immune system responses
• Mood
• Mucus and saliva production
• Skin and muscle sensations
• Speech
• Taste
• Urine output

The vagus nerve travels from the brain toward the neck, chest, and abdomen. The name “vagus” is derived from the Latin word for “wandering.”

The vagal nerves emerge from the medulla oblongata of the lower brainstem and then travel through the:

• Neck (between the carotid artery and jugular vein)
• Chest (thorax)
• Heart
• Lungs
• Digestive tract and abdomen

The vagal nerve branches include the following:

• Inferior ganglion branch that supplies the larynx and pharynx with nerves and muscles
• Superior ganglion branch that supplies the spine and ear with nerves
• A branch that supplies the heart, lungs, and esophagus with nerves

The following conditions can affect the  vagus nerve:

• Gastroparesis: When a vagus nerve is damaged, food cannot pass from the stomach into the intestines, resulting in gastroparesis. Diabetes, viral infections, abdominal surgery, and scleroderma are other conditions that can harm the vagus nerve.
• Vasovagal syncope: Fainting is often referred to as syncope. Vasovagal syncope is a condition where your heart's vagus nerve overreacts to conditions such as intense heat, anxiety, hunger, pain, or stress. Orthostatic hypotension is a rapid drop in blood pressure that can make you feel lightheaded or faint.

Depending on the damaged area of the nerve, vagus nerve disorders may result in a variety of symptoms:

• Bloating and discomfort in the abdomen
• Gastroesophageal reflux disease
• Variations in blood pressure, blood sugar, or heart rate
• Sucking difficulties or a loss of gag reflex
• Light-headedness or fainting
• Voice loss, wheezing, or hoarseness
• Decreased appetite, a sudden feeling of fullness, or unexplained weight loss
• Nausea and vomiting

To diagnose a vagal nerve disorder, your doctor might recommend one of the following tests:

• CT or MRI scans to check for intestinal obstructions
• Echocardiogram to evaluate heart health
• Gastric emptying solid study or smart pill (an electronic substance you ingest) to determine how long it takes for food to pass through your stomach into your intestines
• Upper endoscopy, which examines the upper digestive tract

Treatment for vagus nerve symptoms may include:

• Dietary adjustments for gastroparesis
• Drugs to reduce nausea and abdominal pain, control blood sugar levels, and enhance stomach emptying
• Feeding tubes to supply nutrients
• Gastrostomy to enlarge the stomach to release pressure
• Gastric electrical stimulation to activate the stomach's muscles and nerves and drive food through the intestines

Vasovagal syncope may be treated by:

• Eating a diet heavy in salt
• Stopping blood pressure-lowering medications, such as diuretics
• Taking medications to increase blood pressure, salt levels, and fluid balance or calm nervous system reactions
• Compression stockings that prevent blood collection in the legs

You can keep your nervous system healthy by making the following lifestyle changes:

• Eat a balanced diet
• Engage in regular exercise
• Control blood pressure levels and diseases such as diabetes
• Practice yoga or meditation

Breathing deeply and slowly from the abdomen is one of the key ways to encourage the proper function of the vagus nerve. You can learn to employ breathing techniques to divert your attention from tension or discomfort. 

Most people tend to stop breathing and hold their breath when there is anticipated stress. However, holding your breath triggers the fight or flight response and exacerbates feelings of discomfort, stiffness, or anxiety.

Vagus nerve stimulation involves taking deep breaths through your nose and mouth:

• Take slower breaths (aim for 6 breaths per minute).
• Use your abdominal muscles to breathe (as you inhale, visualize enlarging your rib cage and abdomen)
• Exhale longer than inhaling (the relaxing effect is brought on by exhaling)

The following other methods can activate the vagus nerve:

• Vocal cords: Loud singing or water gargling may stimulate the vagus nerve.
• Foot massage: Firm or mild pressure may help stimulate the vagus nerve.
• Cold water face immersion: Submerging at least two-thirds of your cheeks, eyes, and forehead in cold water can stimulate the vagus nerve, which lowers the heart rate, stimulates the intestines, and activates the immune system.
• Vagus impulses: Fiber slows down gastrointestinal movements and increases the feeling of fullness after meals.
• Laughter: Laughter activates the vagus nerve, improves mood, and strengthens the immune system.

Stressful situations do not always negatively affect the body and thoughts. Activate the vagus nerve to inform the body that it is time to unwind and decompress, which has a long-term positive effect on the mood, ability to handle pain, well-being, and resilience.

Through a device that resembles a pacemaker, vagus nerve stimulation (VNS) sends regular, gentle electrical pulses to the brain through the vagus nerve. People typically cannot feel the pulses (vibration) during surgery because the brain is not physically involved. 

VNS has been authorized by the FDA to treat epilepsy and depression that do not respond to conventional therapy. It is crucial to remember that VNS is only a treatment choice for a select group of people with epilepsy (seizure disorder) or treatment-resistant depression:

• Electrical impulses stimulate the left vagus nerve. The device and nerve are connected by a wire that goes beneath your skin.
• The device communicates painless electrical signals through your left vagus nerve to the brain. These impulses minimize irregular brain electrical activity.

Furthermore, researchers have investigated its potential for the treatment of the following conditions:

• Pain
• Cluster headaches
• Inflammatory bowel disease
• Post-traumatic stress disorder
• Rheumatoid arthritis