What is the vagus nerve?
The brain is connected to the body through a network of 12 important nerves that branch out through the spine and throughout the body, and the vagus nerve is perhaps one of the most important: its tendrils influence digestion, the heart, reflexes, and breathing.
It’s easy to see why scientists are so intrigued by the function of the vagus nerve, which is essentially a highway connecting your brain to your body, especially when you consider how all of the above affects your mood.
Function of the vagus nerve
The vagus nerve is responsible for many of the slower “rest and digest” responses that are collectively known as the parasympathetic nervous system, as opposed to the rapid “fight or flight” responses that are under the control of the sympathetic nervous system. The nerve itself is actually two thick bundles of individual neurons (nerve cells) that originate in the brain and travel through left and right openings in the base of the skull to the rest of the body.
Most of the individual neurons that make up the vagus nerve are sensory neurons – there are about 100,000 of them on each side of the human body – that carry messages from the organs to the brain and are activated by sensory input from the environment. The rest are motor neurons that send messages in the opposite direction, from the brain to the organs, and directly control all muscle movement.
Why is the vagus nerve so important?
The vagus nerve is the polymath of the parasympathetic nervous system, responsible for everything from breathing, heart rate, swallowing, sneezing, digestion, appetite, immune response, and even orgasm.
The broad capabilities of the vagus nerve result from the wide variety of neuronal cell types at its disposal. Different types of sensory signals They sense signals from a variety of organs: some are chemical, like oxygen levels in the blood or secretions from gut bacteria, while others sense mechanical signals, like the stretching of blood vessels or the intestines.
So the neurons of the vagus nerve mainly convey information about what’s happening in the rest of the body to the brain, which interprets this information and acts on it to maintain internal conditions. But the few neurons that send signals in the other direction also have important functions, such as communication between the brain and the gut, and certain muscles in the mouth and throat that control speech and the gag reflex.
The functions of the vagus nerve are so numerous and varied that it’s very likely that there are roles for it that we haven’t yet discovered. But we do know how we can harness the vagus nerve.Valsalva maneuver It activates the vagus nerve, slowing a fast heartbeat and calming palpitations. This may involve coughing, straining to go to the toilet, or, perhaps most bizarrely of all, doing a handstand.
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Long and tortuous nerves
The word “vagus nerve” comes from the Latin for “wandering,” and that’s exactly what the vagus nerve is. It’s a bundle of nerves that runs down to the base of your spine and colon, branching out along the way to vital organs like your heart, lungs, liver, and intestines.
The vagus nerve, the longest cranial nerve in the body, is a major component of the parasympathetic nervous system, which controls automatic bodily functions such as digestion when the body is at rest. The vagus nerve was historically known as the pneumogastric nerve because it innervates both the lungs and the stomach.
How does the vagus nerve relate to our health?
In stressful situations, the sympathetic nervous system’s fight-or-flight response kicks in, allowing you to respond quickly, while the parasympathetic nervous system works slower and promotes a more restful state, which is essential for relaxing and calming down after experiencing stress.
With the help of the vagus nerve, the brain recognizes when, for example, breathing or heart rate is speeding up and puts the brakes on. The sympathetic and parasympathetic nervous systems are not always in sync, working separately or more in concert, but in theory, their activity can become unbalanced in certain situations. These include intestinal disorders and psychiatric illnesses. Sustained stress is thought to be the cause of sympathetic overdrive, and researchers say they can detect this in patients with depression, for example.
Vagus nerve and heart
One of the most commonly used indicators is Heart rate variability – Variability in the intervals between successive heartbeats. Because a healthy heartbeat is somewhat irregular in rhythm, less variability is said to be associated with an increased sympathetic nervous system, meaning the body is constantly in fight-or-flight mode, with the vagus and parasympathetic responses struggling to keep up.
But despite its widespread use, questions remain about the extent to which heart rate variability is useful as an indicator of the balance between the parasympathetic and sympathetic nervous systems. Heart rate monitors provide this information, but you shouldn’t get obsessed with the numbers.
What happens if the vagus nerve is damaged?
In the past, stomach ulcers were often treated by cutting the fibers of the vagus nerve below the rib cage, as the nerve was thought to play a central role in secreting the stomach acid that causes ulcers. Modern medicines have reduced the need for this type of surgery, but it shows what can happen when a nerve with many branches becomes damaged.
In fact, a “vagotomy” cuts off the vagus nerve supply to the stomach, pancreas, small intestine, and parts of the colon, potentially leaving the patient unable to expel solids without further surgery on the intestine. Patients with gastroparesis have a similar problem, but in this case the symptoms are usually due to damage to the vagus nerve caused by diabetes, drugs, or infection.
However, when the vagus nerve is damaged at a higher level, the effects are quite different. For example, the chickenpox virus attacks the nervous system and is known to cause the following rare symptoms: Vagus nerve disorder As a result, patients can lose the ability to swallow and may also suffer from headaches and ear irritation. Early data collected by Spanish researchers suggests that some of the symptoms of long COVID may also be related to damage to the vagus nerve, including problems with breathing, speaking, and defecation.
Should I get a vagus nerve stimulator?
From the evidence so far, Vagus nerve stimulation It’s safe. But researchers remain concerned that the growing use of neurostimulators at home may come with risks that we’re not yet aware of.
Those who prefer mindfulness over being tied to a machine are turning to activities such as yoga, meditation, hypnotherapy, and deep breathing, all of which are thought to increase parasympathetic nervous system and vagus nerve function. Swimming or bathing in cold water, or simply Splash cold water on your face It can stimulate the vagus nerve and activate the parasympathetic nervous system.
Of course, buying a cheap in-ear device or going on a yoga retreat may seem like an appealing solution when you’re feeling unwell, but if you have any serious health complaints, it’s always best to see a doctor.
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What is Vagus Nerve Stimulation?
The concept of vagus nerve stimulation dates back to the late 19th century when neurologist James Leonard Corning developed an electrical stimulation device to treat people with epilepsy. Although it was not used as a medical treatment at the time, today more than 100,000 people have received vagus nerve stimulation via a chest or, more rarely, brain implant to treat epilepsy when previous medications have not worked.
The implants can reduce seizures by up to 75 percent in some people, and studies have shown that the longer the implant is worn, the better it works. Manufactured by US medical technology company Cyberonics, the device is also approved to treat severe depression and headaches.
Nerve stimulation doesn’t necessarily mean surgery. You can access the vagus nerve. Through the ears and neck branches For example, they use devices similar to the inexpensive TENS machines commonly used to relieve labor pain. Ear clips are widely sold as TENS attachments, but Nurosim We produce stylish neuromodulators for people who want to try our approach to anxiety, depression, and fatigue.
Scientific research into vagus nerve stimulation is currently exploding, with trials being conducted for a variety of conditions, including burns, obesity, high blood pressure, rheumatoid arthritis, Alzheimer’s disease, and tinnitus. The close relationship between the vagus nerve and intestinal function It’s also being touted as a potential treatment for common gut disorders like IBS, though as with any condition, the process of gathering evidence from trials to support its use is slow.
5 things you need to know about the vagus nerve
- This is the longest cranial nerve, running from the brain to the large intestine, sending signals in both directions via neurotransmitters and gut hormones.
- The fibers of the vagus nerve contain 200,000 sensory nerve cells. The only place where sensory vagus nerve fibers reach the surface of the body is the ear.
- It is believed that a vagus nerve “bypass” – sending impulses directly between the uterus and the brain – could enable women with spinal cord injuries to achieve orgasm.
- Because vagus nerve stimulation affects the gamma-aminobutyric acid neurotransmitter associated with ADHD, scientists have proposed it as a potential treatment.
- The scientific name for fainting is vasovagal syncope, which occurs when the vagus nerve becomes overstimulated, causing a sudden drop in heart rate and blood pressure.
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