Cranial nerve X. It sounds like a pretty rad superhero, or maybe the superhero’s genius sidekick who comes up with all the cool gadgets and never gets credit for being the one who actually foils the villain’s evil plans.
Cranial nerve X, aka cranial nerve 10, aka the vagus nerve, is neither of those things, but it IS pretty rad. The vagus nerve is a cranial nerve complex that runs from the base of the brain down through your trunk, branching out like a tree and sending “roots” out to communicate with your internal organs and glands.1When we talk about the undeniable power of the mind-body connection, we’re usually referring to the vagal nerve’s actions.
What Is the Vagus Nerve?
The vagus nerve is the core of your parasympathetic nervous system. You might remember that your autonomic nervous system comprises two parts: the sympathetic “fight-flight-freeze” nervous system and the parasympathetic “rest-and-digest” nervous system. Well, you can’t rest and digest without the vagus nerve. Think of it as an information superhighway. It collects information from your organs and translates it into messages that tell the brain, “Everything is cool down here!” or “Yikes, something bad is going down! Time to get the sympathetic nervous system involved.” It also carries directives from the brain to the body.
To put it simply, the vagus nerve modulates the stress response and facilitates our ability to maintain homeostasis. Some people describe the vegaus nerve as a “brake” on the sympathetic nervous system, but I don’t care for that analogy. It implies that when you’re in fight-flight-freeze mode, you’re “on,” and when you’re highly parasympathetic (resting and digesting), you’re off.
That’s not accurate. All the good stuff—growth, repair, emotion regulation, social connectivity—happens in parasympathetic mode. You definitely want to be parasympathetic dominant or vagal dominant.
The term vagal tone refers to how active the vagus nerve is, which is an index of parasympathetic nervous system activity. Higher vagal tone = more parasympathetic = less physiologically stressed.
Heart rate variability (HRV) is an indicator of vagal tone, with higher HRV correlating to higher vagal tone. Decreases in heart rate, respiratory rate, and blood pressure all indicate increased parasympathetic nervous system activity, so they can also be proxies for vagal tone. Any practices that increase HRV or lower one of those cardiorespiratory markers increase vagal tone.
Research is showing that we can intentionally activate the vagus nerve and thereby alleviate physiological stress. One of the simplest ways to do so is by modulating our breathing. It sounds too good to be true, but you can literally affect your biochemistry almost instantaneously by changing your breath. Breathwork is becoming more popular in the health, fitness, and longevity spheres. With it, we’ll see a growing interest in the vagus nerve and how we can hack it to relieve the chronic stress endemic to modern life.
I’m making my prediction now: the vagal nerve is poised to have its own hot girl summer, and I, for one, am looking forward to it.
3 Breathing Exercises to Increase Vagal Tone
The vagus nerve relays information between the brain and the lungs to regulate breathing.2 When you aren’t stressed, your breathing is naturally slow and controlled. Your heart rate also increases with each inhalation and, thanks to the vagus nerve, slows down with each exhalation, a phenomenon called respiratory sinus arrhythmia.3
Normally, these are top-down, or efferent, processes, meaning the brain controls these physiological processes via the vagus nerve. However, there is also a growing body of evidence showing that when we consciously breathe as if we are unstressed, we can essentially tell the vagus nerve that we are, in fact, relaxed.4 The vagus nerve then sends that info to the brain, and voilà, we’ve created our own chilled-out reality.
Those of you with little kids might remember the lesson from Daniel Tiger: When you feel so mad That you want to roar Take a deep breath And count to four
Daniel’s offering some smart, science-backed advice there. That deep breath calms the body and changes your emotional response to a negative situation. Any time you pause and take a few slow, calming breaths, you activate the vagus nerve and put yourself in a more parasympathetic state.5
In the longer term, it seems possible to improve vagal tone and put yourself in a more chronic parasympathetic-dominant state with regular breathwork practices. Here are three to try:
Diaphragmatic breathing entails taking slow, deep, belly breaths. Find a comfortable position, either lying down with your knees bent or seated with your feet on the ground. Place one hand on your chest and the other on your belly.
Inhale slowly through your nose. As you do, you should feel the hand on your belly rise. Exhale gently and feel your belly fall. Think about the air coming in through your nose and all the way into your belly, then up and out again in a smooth wave.
If most of the movement of your breath is in your chest or, worse, your shoulders, that means you aren’t really engaging your diaphragm to pull the air into your body. Keep practicing!
Resonance breathing, also called coherent breathing, means breathing at a rate that allows your breath and heart rate to synchronize. Although we each have slightly different resonant frequencies, research has shown that the average resonance is approximately 5.5 breaths per minute, which works out to 5.5 seconds for each inhale and 5.5 seconds exhale. Cool, right?
According to James Nestor, author of Breath, many traditional religious chants and prayers from around the world had a similar rhythm that would naturally cause people to breathe about 5.5 times per minute.11 This offers a physiological explanation for how prayers, chants, and yogic mantras exert a calming effect.
To practice resonance breathing on your own, find a comfortable position seated or lying down. Take a few slow breaths to calm and center yourself, then begin inhaling for a count of five and exhaling for a count of five. Concentrate on the rhythm of your breathing.
Extended exhale breathing patterns take advantage of the aforementioned respiratory sinus arrhythmia. The vagus nerve is activated during exhalation, so extending the exhale can provide “respiratory biofeedback” and tell the brain you are relaxed.14
There’s not enough research to pinpoint an optimal ratio, but I’ve seen both 4:8 and 4:10 recommended. That means inhaling for four seconds, pausing, then exhaling for eight to ten seconds. It probably doesn’t matter which you do, as long as the exhalation is longer than the inhale. If this is too challenging to start, try a three-second inhalation and a seven-second exhalation.
Putting These Breathing Exercises into Practice
You can perform these exercises anytime, anywhere. Next time you’re feeling stressed while stuck in traffic or the slowest line at the grocery store, try inhaling for four seconds and exhaling for eight seconds. See if you don’t start to feel calmer almost immediately.
Ideally, you should make breathwork a consistent practice, much like meditation. In fact, breathwork is a form of meditation. Pick one of the exercises above and start by doing one or two five-minute sessions each day. If you can do ten minutes, all the better. Work up to longer sessions, up to twenty or thirty minutes once or twice a day. Try breathing through your nose as much as possible.
If that sounds like a lot, start with what you can do. You’ll probably find that you’ll start to crave the benefits. As you start to improve vagal tone and experience more calm, less stress, and better emotion regulation, it becomes self-reinforcing. You want more.
The good news is it’s likely that many of the foundational Primal lifestyle behaviors also improve vagal tone. That’s likely one pathway by which they improve health and wellbeing. Stay tuned for part two of this series, where I’ll talk about how this might work. It’s very rad indeed!
Lindsay Taylor, Ph.D., is a senior writer and community manager for Primal Nutrition, a certified Primal Health Coach, and the co-author of three keto cookbooks.
As a writer for Mark’s Daily Apple and the leader of the thriving Keto Reset and Primal Endurance communities, Lindsay’s job is to help people learn the whats, whys, and hows of leading a health-focused life. Before joining the Primal team, she earned her master’s and Ph.D. in Social and Personality Psychology from the University of California, Berkeley, where she also worked as a researcher and instructor.
Lindsay lives in Northern California with her husband and two sports-obsessed sons. In her free time, she enjoys ultra running, triathlon, camping, and game nights. Follow along on Instagram @theusefuldish as Lindsay attempts to juggle work, family, and endurance training, all while maintaining a healthy balance and, most of all, having fun in life.