Some families give thanks before dinner each night. Others pray or share highlights from their day. Dr. Navas Habib and his children hum.
Habib, a functional medicine expert in Canada and author of the book Activate Your Vagus Nerve, began this unconventional ritual as a way to strengthen the vagus nerve. He’s far from the only healthcare provider evangelizing about the calming benefits of the longest nerve in our bodies.
The vagus nerve is a thick power cord that connects the brain to the gut. It keeps the autonomic nervous system (the part that controls involuntary bodily processes) running smoothly, and it regulates the physiological response to stress.
Scientists found they could treat medical conditions including treatment-resistant epilepsy and depression using nerve stimulators, which are implants that send electric shocks to the vagus nerve, in the 1980s. Then, in the mid-1990s, a scientist proposed a new theory, called polyvagal theory, which reclassified the vagus nerve’s role in the autonomic nervous system. This game-changing advancement set the stage for self-guided vagus nerve training to go mainstream — but it took some time.
“The function of the vagus nerve and increasing vagal tone was not something I learned about in graduate school,” Talkspace therapist Liz Kelly says. “In the past few years, however, I have seen more clinicians talking about polyvagal theory as a tool to support clients.”
Today, in addition to coming up more often in CBT sessions and doctor’s visits, the vagus nerve is the star of best-selling wellness books like The Body Keeps the Score and trending TikTok videos, where therapists model simple exercises, like the Habib family’s humming, to help people manage issues including depression and anxiety.
“How our physical body and nervous system interact [impacts] how we show up every day,” Habib says. “For me, the vagus nerve has always been this really important piece of the puzzle.”
The vagus nerve is as dizzyingly complex as it is compelling. If you’ve heard or read about it and you only sort of know what it is or why it seems poised to become the next buzzworthy health topic, you’re not alone. Even experts like Catchings tend to go from A to Z pretty quickly when telling the story of the vagus nerve. But it’s worth going a little deeper. In some goal-oriented therapies, such as CBT, the first part of changing an unhealthy behavior or thought pattern is understanding it.
Similarly, it might be easier to embrace humming as a mental-wellbeing strategy if you can explain why “practice an annoying noise” should be the prelude to “keep calm and carry on.”
Scientists and doctors have been tinkering with the vagus nerve for more than a century. In 1921, neuropharmacologist Dr. Otto Loewi discovered the vagus nerve sends chemical (not electrical) signals throughout the body, later winning a Nobel Prize. The other most notable advancement in the vagus nerve space is more recent: In 1995, Dr. Stephen Porges published his polyvagal theory.
Essentially, Porges proposed a new way to characterize the vagus nerve’s functions within the autonomic nervous system. But by challenging long-held views about the number and configuration of nervous-system branches, Porges achieved a breakthrough in our ability to harness the power of the vagus nerve for mental health.
Quick science lesson: The autonomic nervous system is the part of the peripheral nervous system that controls bodily functions outside conscious effort. It also interprets if social cues and other environmental stimuli — your coworker’s facial expression after you confess a mistake, a sudden noise — pose a real threat or not.
If you think of your autonomic nervous system as an air field, the vagus nerve is the air traffic controller. Within the ANS, the vagus nerve controls the parasympathetic and sympathetic nervous systems. Experts have traditionally said these systems work together to control heart rate, among other bodily functions — based on those environmental cues. Let’s say your nervous system perceives your coworker’s eye roll as a threat. Your sympathetic nervous system would then step in and release stress hormones to help you fight or flee this sense of danger, increasing your heart rate. Then, to calm you down, your parasympathetic nervous system would send in its own army of different chemicals to counteract the stress chemicals.
Porges suspected the ANS was more complicated than that. He theorized that a specific area of the vagus nerve, the part near your face and heart, is responsible for that parasympathetic calming, grounding response. So, when you activate the upper part of your vagus nerve, through deep breathing, humming, or singing, you can immediately flood your body with feelings of calm, lowering your heart rate.
“I talk about it with my anxious clients the most,” says Talkspace therapist Cynthia Catchings. “They seem to understand the concept easier when discussing the gut feeling or discomfort felt in the stomach when they are anxious. Although most of them recognize the feeling, they do not have a name for it, so discussing the vagus nerve also brings the scientific awareness and knowledge some of them need.”
Habib says to think of the nervous system as an “instrument.” If the calming part of your vagus nerve is “toned,” it will operate more effectively in general — allowing a faster shift from stressed out, to cool and collected.
“In a sympathetic state, people typically feel out of control, angry, irritated and reactive,” says Kelly. “A focus of therapy from a polyvagal perspective is helping clients move from emotional dysregulation, a state of either feeling numb or hyper-aroused, to a sense of calmness and security.”
In fact, research shows that looking at heart rate variability can show us how “toned” your nerve may be. But HRV, which measures variation in the amount of time between each heartbeat, can be tricky to understand. It’s actually inversely related to your heart rate.
If you’re in more of a relaxed mode on a daily basis, you’ll likely have a higher HRV. This correlates with a high “vagal tone.”
Patients suffering from depression or anxiety often sit in their nervous system’s stress responses more often than they need to. Studies show these types of patients have lower HRVs, because their nervous system’s responses aren’t moving as quickly. These patients have low vagal tone.
Catchings encourages her most anxious clients to strengthen their vagus nerves through “singing, humming, breathing exercises or meditating.” A 2018 paper concludes that stimulating and “toning” the vagus nerve through deep breathing, especially within contemplative practices like yoga and meditation, slows down your heart rate, improving its variability, and has “shown a similar pattern of beneficial effects on health, mental health and cognition: mostly in stress-related conditions and performance.”
A 2019 study echoes these findings, adding that taking deep breaths can also help you make better decisions in the long run. Others suggest that it’s helpful to think of the vagus nerve as a muscle, and that to really maximize its strength through training, you need to test its limits. Similarly to how high-performance athletes ice their muscles between workouts, you can “ice” the vagus nerve by splashing cold water on your face in the morning or taking cold showers.
So the next time you’re feeling stressed out, you might want to hack your vagus nerve by pulling out your favorite meditation app or belting out show tunes during a cold shower. Don’t worry — even if your tune is off, you’ll still tone your vagus nerve.