The role of nerves and the nervous system, in general, is to carry important messages from the brain and spinal cord to the rest of the body. This information allows us to enact, stimulate or suppress vital bodily functions like respiration, digestion and movement. The vagus nerve — also known as the ‘wandering’ or ‘vagrant’ nerve — is one of these key communicators and sits in the presidential seat when it comes to regulating our ‘rest and digest’ bodily functions.
This enquiry will clarify the function of the vagus nerve and explain how to stimulate and tone it. We’ll take a look at why ancient practices such as yoga and chanting hold a valuable relationship to this nerve.
What is it?
The vagus nerve is the longest in the Autonomic Nervous System (ANS), so it plays a vital role in automated processes like digestion, breathing and the beating of the heart. By connecting the brain to many areas of the upper body, this nerve is a key messenger that regulates lung, heart and digestive tract functioning.
When we stimulate our vagus nerve, we promote better digestion, reduce the production of stress-related hormones and encourage a healthy state of rest in the body through lowered heart rate. There are several known ways of stimulating the vagus nerve such as:
Certain breathing techniques make use of both the prolonged exhale, lower abdominal and pelvic floor contraction, which results in greater vagal nerve stimulation and deeper feelings of restfulness. This is especially valuable if there is an extended pause between the end of the exhale and subsequent inhale increasing CO2 levels in the blood, vasodilation and improved oxygen uptake in the cells of the body.
High vagal nerve tone improves blood/glucose levels which can, in turn, reduce the likelihood of diabetes. It is also believed that cardiovascular health improves too. Low vagal nerve tone is often reflected in high levels of inflammation in the body, raised levels of the stress hormone cortisol as well as symptoms of depression.
The Om chant
The sacred ‘Om’ chant is used in the Hindu, Buddhist and Jain Dharma religions, and also many yogic practices. It is used to feel a sense of calm, bring awareness into the present and offer a meditative perspective for those who take part. Although we may not need or even want proof for the medicinal or wellbeing value of this to practice, scientific evidence has indeed confirmed some things about the ‘Om’ chant.
Enquiry (Kalyani et al. 2011) has shown that the vibration in the vocal cords caused by the chanting of ‘Om’ has a stimulating effect on the vagus nerve and parasympathetic nervous system. Vagal nerve stimulation treatment is used for depression and epilepsy and ‘Om’ chants are now also being considered in treating these conditions.
Another study (Kumar et al. 2010) found that Om chanting promotes a state of mental alertness with physiological rest, as well as a decrease in sensory transmission time in auditory cortices, thus heightening auditory perception.
The nature of yoga in relation to the vagus nerve is that it involves a disciplined approach towards breathing. All yogic practices rely on controlling the breath and in most yogic practices, extending the exhalation is used as a way to deepen a stretch or pose.
This disciplined breathing is partly responsible for the sense of relaxation that follows a yoga session and as we now know, regulating the breath and extending exhalation results in vagus nerve stimulation (VNS). This means a lowered heart rate, breathing rate, improved digestive function and promoted restfulness in the body.
Beyond yoga, it has been shown that the overlap between contemplative actions and VNS tend to involve a disciplined approach to breathing. Therefore, many practices in addition to yoga, such as Tai Chi and meditation also have valuable benefits to vagal function.
To put it humbly, the vagus nerve is a big deal. Now living in times that are increasingly stressful to human beings, the importance of de-stressing and calming the mind and body is paramount. These days we work through laptops in anxiety-prone, hunched-over positions and we communicate through mobile screens and emojis.
It’s not all bad, but without a counter-balance, our contemporary lifestyles can easily surpass the boiling point of what is manageable. Engaging with the practices mentioned, like simple breathing techniques, can help to bring a natural state of calm and balance out the stress of contemporary living.
With increasing support from scientific research, and millennia of tradition behind some of the practices, it’s worth considering how stimulating your vagus nerve could be a source of immense, yet calming reward.
Fenella Lindsell is a yoga teacher and yoga teacher trainer.
If you are a yoga teacher, you will certainly appreciate the importance of the iliopsoas muscle, also known as the psoas.
If you are not a teacher, then you may well have heard of this large muscle that runs from the hip to the lumbar spine insertion and takes charge of back flexion and extension as well as hip flexion.
The following discussion will explain and analyse the link between the psoas muscle and the human fight or flight response.
In addition, some tips will be outlined for stretching, strengthening and relaxing the muscle with the ubiquitous outcome of a healthier quality of life and lower stress.
Primarily, the psoas muscle relates to bodily movement in the spine, hip and legs. The psoas is the deepest core muscle and connects from the mid-lower spine (12th thoracic vertebrae to the 5th lumbar vertebrae) and from here, it travels down through the hip and lastly to the femur.
The psoas is the only muscle that connects the spine to the legs and without it, we wouldn’t be able to bend over, lift our legs or keep our back from flopping over, not to mention its important connection to the diaphragm and breath.
Further, it has particular importance for stabilising the lower back, so when the muscle is overworked or unusually tight, the lower back has to take on more labour in its own muscles to keep the back stable.
Here is made evident the close link between the psoas and lower back problems.
Stretching, despite the idealised imaginations of some aspiring yogis, sadly doesn’t solve everything. It is important to know how the health of your psoas muscle is because this indicates whether it needs strengthening, stretching, relaxing or releasing.
Yoga is not a science, nor should it be seen in the same rationalistic and reasonable sense as we see traditional science in the West. Yoga is a practice that should be done for no other reason than to be present and communicate silently with your mind, body and breath. Nonetheless, the developing science around yoga can help us apply the practice in broader medicinal and educational ways based on truths we can reveal about this ancient tradition. We’re here to take a look at the science of yoga, and what this means for practitioners, educators and physicians.
Where did it all begin?
The ayurvedic tradition emanates from the Indian sub-continent and has been practised for over two thousand years. It involves alternative approaches to medicine based on a mixture of herbal, meditative, dietary and yogic practices. This may be seen as the first science of yoga.
The modern ayurvedic tradition was largely influenced by N.C. Paul, a Bengali physician who began some of the first medically studied effects of yoga and was responsible for spreading them to a wider western audience.
Founders of the science of yoga:
Figures like Shri Yogendra helped begin what is now known as the modern yoga renaissance. He was a yoga guru, researcher, author and poet who established The Yoga Institute in 1918, which is now the oldest yoga institution in the world.
Another noteworthy figure in developing the science of yoga, linking yoga to the West and developing the contemporary understanding of yoga we have today was Kuvalayananda. Also a guru, researcher and educator, he founded the first journal dedicated solely to yoga, titled ‘Yoga Mimasa’. The Sanskrit for Mimasa means reflection, investigation, profound thought, or examination. He saw it as his duty to educate on the importance of physical health through yoga practice.
It is largely thanks to these founding enthusiasts that the revival of yoga has found sturdy legs in the United States and Europe, culminating over the last hundred years to its peak of practice today in the West. With these figures to thank as catalysts for yoga research, it is interesting to see what contemporary science has discovered to be true of this ancient practice.
The science today
Sometimes frowned upon for its tranquillity as a mode of exercise, yoga might take some adjustment for your average High-Intensity Interval Trainer used to fast-paced and exhilarating pressures on the body.
Despite the unusually slow pace of practice compared to some exercises, many top athletes from all ranges of activities from skateboarding to archery are utilising yoga for more than just its physical benefits.
Contemporary science has proven that yoga is associated with lower stress levels and other positive changes to the body and mind.
A study of the existing literature by Pascoe et al, 2015 found that the large majority of the studies provide evidence that yoga is associated with positive biological changes in blood pressure, heart rate, cortisol or cytokine levels. (Cytokines are substances that assist in the functioning of immune response cells.)
The nature of yoga practice is deeply centred around breathing to:
Elongate stretches as we exhale
Demarcate the start and end of a pose (i.e. hold for five breaths)
Bring practitioners into a state of presence through sustained awareness of the breath
Yoga often relies on diaphragmatic breathing, or deep breathing, which involves contracting the diaphragm and breathing deep into the belly. As yoga research has evolved, the evidence for the benefits of diaphragmatic breathing has shown: “it may also help in reducing stress; treating eating disorders, chronic functional constipation, hypertension, migraine, and anxiety and diaphragmatic breathing appears to be effective for improving the exercise capacity and respiratory function in patients with chronic obstructive pulmonary disease.” (Hamasaki et al, 2020).
A final and more frequently mentioned finding in the science of yoga is that the practice is associated with:
Improved joint strength through endurance practice
Improved joint mobility through active (rather than passive) stretching
Improved muscle strength and muscle mobility
Injury rehabilitation (particularly for lower backs)
These physical benefits have been claimed for decades but research now shows that they are true. Work from the likes of Cramer et al 2013 and Gustav et al 2013 and 2015 have helped solidify this truth through scientific methods.
Thanks to the dedication of yoga gurus who saw the universal potential of yoga science some centuries ago, the culture has spread throughout the world and now rests, respected by groups of all kinds. As the science of yoga evolves, so may our understanding of its benefits. In a time where science is becoming the grounding truth of contemporary belief, the scientific foundations of yoga have ever-increasing importance in our lives.