In Latin, the word for “wandering” is vague. Appropriately, the vagus nerve is known as the “wandering nerve” due to its long path through the human body. It’s an exciting target in the world of science as a growing number of studies suggest electrical stimulation can improve outcomes for people with a variety of conditions, from treatment-resistant depression to post-traumatic stress disorder.
The vagus nerve is also a darling of the wellness industry — but that’s where things get tricky. Millions of people watch videos of vagus nerve exercises that promise to “rewire” the brain on social media. The #vagusnerve hashtag has been viewed at least 45.9 million times on TikTok alone. If you search “vagus nerve” on Instagram or Google, you’ll find thousands of people claiming the ability to teach you how to live a better life by “resetting” the nerve. In turn, Google Trends shows a steady increase in interest over the past five years for the vagus nerve as a whole. Yet the science is murky at best.
Scientific evidence for the purported benefits of these vagus nerve exercises, activations, and resets is inconsistent and sparse. However, a growing number of studies support vagus nerve stimulation with electrical impulses as a treatment for various conditions.
This difficulty in explaining the benefits people experience when following guidance around the vagus nerve may be partly due to confusing influences. What’s taught as vagus nerve exercise, for example, often involves deep breathing and mindfulness — studies that show mental health benefits. But it is difficult to know the exact mechanism that may explain the benefits people experience when engaging in these practices.
“I think it’s fair to say that we still have a lot to learn.”
Christa McIntrye is an associate professor at the University of Texas at Dallas and studies the emotional modulation of memory storage. Through her research, she discovered that electrical stimulation of the vagus nerve promotes memory consolidation and synaptic plasticity, and reduces anxiety. His work suggests that vagus nerve stimulation can improve treatments for PTSD and anxiety.
She is also not convinced that vagal activity can be controlled by actions like deep breathing. That makes sense in theory, she says, but tells me “it’s not possible to confirm that every time someone takes a deep breath, it stimulates their vagus nerve in a beneficial way.” This is why his team uses direct electrical stimulation.
“Some may be willing to make evidence-based inferences that exercise and deep breathing may have beneficial effects, but I know of no controlled, powerful studies showing that these effects are mediated by the vagus nerve,” says McIntyre. . “I think it would be fair to say that we still have a lot to learn.”
What is the vagus nerve?
To understand what we know and don’t know about the vagus nerve and mental health, we need to start by knowing what the vagus nerve is. It’s the longest and most complex of the cranial nerves, and it runs down both sides of our neck, extending from the brainstem to the abdomen.
It represents the main component of the parasympathetic nervous system, which controls the body’s rest and digestive response. As a result, the vagus nerve helps coordinate the interaction between your breathing and your heartbeat and transmits signals from the digestive system to the brain.
“It’s what we call a bidirectional nerve, in that it sends information both to and from the brain,” Simon Cork tells me. Cork is Honorary Lecturer at Imperial College London and Lecturer in Physiology at Anglia Ruskin University Medical School. He studies the role of the vagus nerve in gut-brain communication.
“Information from the brain has effects such as stimulating digestion and reducing heart rate,” Cork explains. “Information sent to the brain includes things like blood pressure and nutritional status.”
Can Vagus Nerve Exercises Relieve Anxiety?
Most vagus nerve exercises involve a variety of gentle movements — like tilting your head to the side and moving your eyes — and deep breathing. And while these actions may benefit you, it doesn’t necessarily have to do with your ability to activate the vagus nerve, Cork explains.
I asked her to watch a video called “Vagus Nerve Exercises to Rewire Your Anxiety Brain”. It has been viewed over 2.7 million times and is just one of many vagus videos made by its creator, Sukie Baxter. In the video, Baxter explains how his work is inspired by the book Access the healing power of the vagus nervewhich is itself supported and inspired by Stephen Porges, a scientist at Indiana University’s Kinsey Institute and professor of psychiatry at the University of North Carolina.
Porges champions and studies the polyvagal theory, which claims a link between the vagus nerve, emotional regulation, and social connections that may explain how we process trauma. It is both widely cited and embraced by some mental health practitioners, and criticized by some for not being backed by empirical scientific research. The debate over whether or not it is pseudoscience is quite contentious.
Beyond this conversation, there is a separate debate about what some purveyors of polyvagal theory say their exercises can and cannot do.
Cork watched the video and found it frustrating. “None of this is based on any scientific foundation whatsoever,” he says.
He explains that being in a calm, relaxed state – which these exercises can influence – can induce a reduction in heart rate, which is mediated by the vagus nerve. But “these videos claim that the exercise itself ‘activates’ the vagus nerve which in turn causes relaxation,” Cork says. “There is no evidence on this.”
“The neuroscience of mental health conditions is very limited and in most cases we don’t yet fully understand the neurobiological basis of conditions such as anxiety or depression,” says Cork. “Statements such as ‘rewiring the brain through the magic of neuroplasticity’ tend to be used because they sound scientific, but in reality these statements – as they are conceived – have no scientific basis. “
Imanuel Lerman, a pain management physician and associate clinical professor at UC San Diego, says “we don’t yet know how deep breathing exercises may or may not cause neuroplasticity” in general and “it’s clear that more work needs to be done to definitively answer this question.”
But he also describes it as “an intriguing question to ask” – in the context of the vagus nerve stimulation.
How can vagus nerve stimulation benefit mental health?
Lerman and his team are studying how stimulation of the vagus nerve can reduce the sensation of pain; their work suggests that the method could be used to alleviate chronic pain associated with PTSD.
Vagus nerve stimulation involves applying electrical impulses to the vagus nerve, either directly or through indirect noninvasive stimulation.
His lab and others are studying whether or not this stimulation can help people with PTSD when used in specific ways. So far, they’ve found that when repeatedly paired with reading traumatic scripts, patients with PTSD seem to show a less anxious response. Lerman’s group is currently investigating whether or not daily vagus nerve stimulation for a week can improve anxiety responses associated with PTSD.
“…vagus nerve stimulation probably decreases anxiety, improves alertness and possibly improves cognition.
Lerman explains that fMRI studies show that subjects who undergo vagus nerve stimulation subsequently activate areas of the brainstem important in norepinephrine signaling (norepinephrine acts as a hormone and neurotransmitter). This increase can “increase arousal, attention, reduce reaction time” and this in conjunction can improve neuroplasticity, he explains.
But so far, the only mental health condition for which vagus nerve stimulation is FDA-approved is major depressive disorder. Up to 35% of people diagnosed with the disease do not respond to conventional treatments; in 2005, vagus nerve stimulation was approved to help people with treatment-resistant depression.
Charles Conway is a professor of psychiatry at Washington University School of Medicine in St. Louis and has studied how vagus nerve stimulation may provide antidepressant benefit to people who typically don’t experience relief after other treatments. These effects usually occur after several months, he tells me.
“Studies of patients with depression support that vagus nerve stimulation likely decreases anxiety, improves alertness, and possibly improves cognition,” Conway says. His own research suggests it may improve the quality of life for people with treatment-resistant depression.
The research is conflicting when it comes to proving a link between these types of benefits and engaging the vagus nerve beyond vagus nerve stimulation. What is certain? Taking time to relax your body and calm your mind is essential for mental health. It may serve you to participate in practices that cause these states – but you may not want to attribute the results to your vagus nerve activation.