Rest & Digest: Yoga, The Vagus Nerve And Wellbeing

Hot Air Or Cool Science?

Yoga is a popular form of exercise that has been shown to have numerous health benefits, notably by reducing stress and anxiety

One of the major pathways for yoga mediated relaxation is through the Vagus nerve, an important mind-body link which plays a key role in down-regulating the body’s stress response

Often dubbed superhighway to healthor physical manifestation of the soul, the Vagus is held up as a veritable holy grail for realizing your dreams and achieving health and happiness. But are these assertions fanciful, or is there some scientific truth behind the hype?

In this article, we’ll explore the science of yoga related to the Vagus nerve, and describe three different exercises using posture, breath and mindfulness to activate the Vagus and boost your physical and mental well-being

Introducing The Vagus Nerve

The vagus is a paired nerve originating in the brain stem and descending through the neck and trunk to supply target organs from the throat all the way to the pelvis. Latin for wanderer (vagrant), the Vagus is the largest nerve in the body, supplying your internal organs via its many branches

The Vagus is a mixed nerve carrying

• motor fibres to the muscles for voice and eating, notably swallowing and gagging
• parasympathetic rest-and digest fibres to most internal organs. Parasympathetic activity is a powerful anti-stress mechanism helping your body recover from a stressful event or period
• and sensory fibres linking the internal organs to the brain. The vagus is the major part of the gut-brain axis, an important pathway for gastrointestinal and emotional health

Electrical stimulation of the parasympathetic Vagus has been used to slow heart-rate, reduce pain and inflammation, and even relieve depression. Though the procedure also has potential for managing pain and inflammatory diseases like rheumatoid arthritis, vagal electrical stimulation is currently licensed only for managing treatment-resistant epilepsy and some cases of depression

Yoga can also activate the Vagus through a variety of breathing techniques as well as postures which stimulate the abdomen, chest and neck. The effects, though immediate are also transient. leading many to doubt the therapeutic potential of such an approach

It’s important to note that the Vagus Nerve is basically a conduit or cable connecting discreet brain areas with the vital organs. The Vagus transmits the outflow of the parasympathetic nervous system, the part of the autonomic nervous system concerned with anti-stress responses. To understand the Vagus it’ll be helpful to take a brief look at the autonomic nervous system

Where Is The Vagus Nerve, And What Does it Do?

The Vagus exits the brain-stem in the lower posterior part of the cranium, then exits the skull, travelling through the neck to be distributed to the organs of the neck, chest, abdomen and pelvis

The Vagus is a mixed nerve, being:

• 80% sensory and 20% motor
• sensory components include include pain sensitivity and interoceptive (see below) sensations from the organs, such as hunger, thirst, fullness and satiety
• its motor functions include control of the voluntary muscles for voice and involuntary muscles associated with eating, notably swallowing and gagging
• it is the principal carrier of rest and digest signals from the parasympathetic nervous system to your internal organs

Rest and digest actions of the Vagus nerve on key organs

Safety, Social Engagement And The Vagus

As stress mobilizes your body’s resources into quick action to deal with a challenge, rest allows your body to replenish its resources

Rest-and-digest parasympathetic activity predominates when you perceive being in a safe environment or situation

The Vagus is also involved in social social engagement. According to the Polyvagal Theory proposed in 1994 by Stephen Porges, professor of psychiatry at the University of North Carolina, safety is the condition for social behaviour to take place in mammals. Eating with friends and family, sharing stories, giving and accepting support and cooperating with your work team are expressions of social engagement.

Think Mediterranean lifestyle: extended mealtimes, outdoor socializing, a clear distinction between work and leisure. It’s not just what you eat, but also how you eat it that lets you rest and digest

Freeze Reactions, Trauma And The Vagus

The Sensory Vagus: Interoception And Emotional Regulation

The vagus is 80% sensory. It’s repertoire includes the sensation of pain,  as well as being the main pathway for interoception: your brain’s ability to listen to the state of your internal organs

A relatively “newly” recognized sense, interoception refers to your ability to sense your inner body. Hunger, thirst and satiety are examples of consciously accessible interoceptive sensations. Interoception is strongly linked with emotional regulation, and engaging with your body’s internal state has been shown to help you manage stress & anxiety and enjoy a felt sense of wellbeing

The Vagus In Health And Disease

By controlling rest-and-digest activity in the body, the Vagus is essential for homoestasis – the maintenance of a stable internal environment.

The Vagus serves as the brain-gut axis, linking the gastro-intestinal tract with your mental wellbeing

It connects the nervous, endocrine (hormonal) and immune systems, orchestrating their activities in the maintenance of health

Vagal activity suppresses the release of inflammatory mediators, notably tumor necrosis factor-alpha (TNFα) from the Spleen to exert a powerful anti-inflammatory effect (Buric 2017)

Hardly surprising then that Vagal activity is associated with improved mental health, from PTSD to anxiety and depression, as well inflammatory disorders including inflammatory bowel disease (Bonaz 2017), arthritis and psoriasis. It plays a significant role in cardiovascular and gastrointestinal health , strengthens the immune system, and may even have an important role in the management of cancer

Vagal Stimulation And Cancer

The Vagus Nerve And Yoga

There is evidence to show that certain yoga postures and breathing exercises can directly stimulate the vagus itself within the abdomen, chest and neck to bring about significant parasympathetic effects

More than just physical exercise, yoga is a mind-body therapy integrating posture and movement with breath-work and mindful awareness to help you become centered, tranquil and happy. Research has linked many of the observed physical and mental health benefits with this contemplative dimension of yoga, citing the parasympathetic nervous system and Vagus as principal mediators (Gerritsen 2018, Sullivan 2018)

How does Yoga Stimulate The Vagus Nerve?

Yoga postures and breathing exercises may exert a direct mechanical stimulation of the Vagus. Though rigorous studies are lacking, there is some preliminary evidence that breathing exercises (pranayamas) and postures (asanas) which stimulate the abdomen, chest and neck give immediate responses indicative of parasympathetic activity. Commonly recommended exercises include

• Kapala Bhati and Bhastrika breathing
• Chest opening back-bends such as the Cobra and Camel
• Inversions such as shoulder and head stand

As already mentioned, the effects are immediate and also short lived. Nevertheless, many have found direct stimulation of the vagus to be a useful tool for getting a grip in situations of high stress or anxiety

Yoga And Cardiovascular Health

Nevertheless, the real power of yoga lies in its practice of mindfulness. As a holistic mind-body intervention (MBI) yoga has been shown to help you relax stress and boost rest-and-digest activity. Research shows that yoga reduces arousal to improve your blood pressure, blood cholesterol profile, inflammation and other important predictors of cardiovascular disease and stroke (Cramer 2014)

Yoga And Inflammation

A 2017 systematic review of MBIs (Buric 2017) showed that mindfulness, yoga, Tai Chi, Qigong, relaxation and breath regulation all produced a down-regulation of inflammation at the gene level. Inflammation is strongly linked to stress and is a major cause of the blood vessel damage leading to fat deposition and narrowing

Numerous systematic reviews have found yoga to be helpful in maladies from back pain, arthritis, fibromyalgia and chronic pain, to migraine, tension headaches, asthma, irritable bowel and mental health, including major depressive disorder

Click the link to read more about the health benefits of yoga

Practical: How To Stimulate The Vagus Nerve With Yoga

Yoga has been shown to have a positive impact on vagus nerve function, leading to improved health and well-being. Yoga breathing and relaxation techniques help activate the parasympathetic relaxation response, promoting a positive feeling of calm and relaxation to stimulate the vagus nerve. Additionally, some yoga poses, such as backbends and inversions help stimulate the vagus nerve and improve its function in the short term. By incorporating yoga into your daily routine, you can help support your vagus nerve and promote better health and well-being

Let’s put theory into practice with some yoga exercises to help you stay chilled and on the ball – in all weathers

The exercise is also a great way to establish the fundamentals for practising all standing postures

Standing Firm: Tadasana, The Mountain Pose

1. Stand with your feet at hips’ width apart. Notice the turn-out (or in) of your feet. The population-average for neutral is your second toe pointing forward. Find your comfortable balance between habit and correct. This is your functional neutral. Do this for each foot. Don’t worry if your feet aren’t totally symmetrical
2. Distribute your weight evenly over the heels and bases of the little and big toes
3. Pull your knees back to lock them straight. Do you feel the reaction at the pelvis? The pelvis tends to roll forward, the lower back hollows, and maybe your tummy juts forward
4. Now, keeping your knees straight let them just relax forward. Feel the base of the spine (sacrum) release down and under? Does your tummy relax back in?
5. Alternate between relaxing and locking your knees a few times, noticing the effects on your posture
6. This time try simply pressing your feet into the ground. Straight down. Firmly. Notice the muscles of the legs and trunk activate? Is there less of a tendency for your bottom to stick back and your belly forward? Let yourself relax

Now we’ve done all that doing, let’s do a bit of undoing

1. Noticing your body weight over your heels, connect with the feeling of pressure. Let your heels sink into the ground, your knees straight, but unlocked
2. Maybe you feel the leg muscles begin to activate? If you’re not sure, press your feet down. Firmly. Then relax, and let them once again drop
3. Can you feel your pelvis rotate backwards as your feet sink, your tail dropping down and tucking under, your pubic bone floating up and back? Maybe you feel the pelvis float up a little, away from the feet?
4. Do you feel your navel float naturally backwards? You’ve just activated, or rather disinhibited the transversus muscle, the deepest layer of abdominal support
5. Now, let’s transfer the awareness up to the head: imagine your head as a ball, the top of your neck a bowl of water. Let the head float on the water
6. With your your gaze forward at eye level, let your head roll on the water so your chin relaxes backwards, towards the top of your throat, and the space between the back of your head and neck opens and softens. You’re still looking forward, not down
7. Can you feel the crown of the head float up and slightly back?
8. Now that your head is free, you can let your neck hang from your head; then allow your upper and middle back, rib cage, shoulders and arms to hang from the neck; now let your lower back hang from your middle back; your pelvis and legs drop from the lower back; your feet sink into the ground
9. Let your head float; allow your feet to drop; linger a while; enjoy

Breathing Calm: Pranayama For The Vagus Nerve

Experimentally and practically, breathing always comes up trumps as a way to connect with the rest-and-digest functions of the vagus

Science loves breathing: it’s quantifiable, practicable and reliably parasympathetic, as evidenced in a recent systematic review entitled: “How Breath-Control Can Change Your Life” (A Zaccaro et al, 2018)

Yoga loves breathing: breath is the primary expression of vital energy in the body. Prana, the vital force of yoga is indistinguishable from the Qi of Chinese medicine. Prana is the living energy we know as health, the spark that animates the body and lights up the mind. When prana moves the mind is thinks and feels. When prana is still the mind is at peace

The exercises below will help you make full use of the breath by allowing the air to fill every available part

The diaphragm is the main muscle of breathing. I’ll be sharing information on the anatomy and functions of the diaphragm in a separate post.

Just as when lifting your arm you’re following an intention to reach for something, not consciously activating the anterior Deltoid muscle, so when you breathe diaphragmatically you follow a set of intentions. Let me show you what I mean

Yoga Breathing Exercise For Vagus Nerve Stimulation – Side Breathing

1. Place your hands over the front of the sides of your lower ribs. Rest your elbows on the ground and keep your hands separate
2. Mentally place a 2lb weight on the underside of the navel. As you inhale your belly will rise, but that little bit of resistance will helps drive the air sideways into the lower ribs. Can you feel that? Your hands resting on the lower ribs will be your guide.
3. Practice taking long, slow outbreaths. At the end of each exhalation wait for the inbreath to start naturally. Let the lower side ribs accept the air as above, then let the breath go slowly and quietly. Practice this for a minute or two

Yoga Breathing Practical For Vagus Nerve Stimulation – Back Breathing

Now, lie on your front, legs extended or flexed in the child’s pose as per the picture. Support your head if you need to, resting your forehead on your hands or a rolled up blanket

1. With pressure on your belly, where does the air go when you inhale? Maybe some of it goes into the upper chest. that’s OK. Does some of the air fill the sides of the lower ribs? That’s even better
2. You can if you want to, place the back of one hand over the lower ribs at the back. Can you allow this area to accept the breath? Try it on the other side
3. Enjoy exhaling long, soft and for a minute or so

Inhabiting Your Body – Mindful Embodiment For Emotional Wellbeing

This simple, yet powerful body scan is a pure body meditation derived from an ancient Buddhist tradition, allegedly taught by the Buddha himself

The last of our three yoga practices for vagus nerve stimulation, this meditation helps you enjoy calm here and now through a felt sense of you own body. There is nothing to do but relax and observe

Sit or lie comfortably in a quiet space. Hit the play button. And enjoy