The tradition of yoga has advanced humankind for thousands of years. Originating from India, the lineage of yoga can be traced back to the Vedic Tradition, around 5000 B.C.E. Then, ancient rishis and sages would practice simple forms of yoga, mainly seated meditation and breath work (pranayama). They were the first human guinea pigs and used there bodies to experiment and uncover the full potential of the human being. Now, approximately in the 21st century, Western Science is unveiling the healing powers of Yoga.

Yoga comprises of 5 primary practices: Asana (postures), pranayama, meditation, chanting and philosophical inquiry. The majority of the research explores the effects of meditation and asana, however the benefits of chanting & breath control are now slowly being uncovered.

This essay is a brief review on the effects of yoga on different systems of the body. I have attempted to find peer-reviewed literature to support the claims made, however due to the lack of research available in some areas, I rely on my own experiences of practicing yoga for 6 years as well as the experiences of my teachers who have been practicing for several decades combined.

Cardiovascular

Cardiovascular disease is one of the largest causes of death in the Western World. We know, both through science and experience, that the cardiovascular system is closely linked with emotional stress. When we are stressed, our heart beats faster or it might even palpitate, our face goes red and blood pressure elevates. Shockingly but somewhat not surprisingly, the most common time for a western man to sustain a heart attack is at 9:30 on Monday morning, just as he enters the office and sits down for work. This one example illustrates the powerful link between the heart and emotions.

The practice of yoga, through stress reduction has been shown to reduce the risk of cardiovascular disease. As this illness is multifactorial, many parameters are usually measured, including cholesterol levels, blood pressure, heart rate, inflammation, blood vessel damage. To quote one study in particular:

“After one year, the yoga groups showed significant reduction in number of anginal episodes per week, improved exercise capacity and decrease in body weight. Serum total cholesterol, LDL cholesterol and triglyceride levels also showed greater reductions as compared with control group. Revascularisation procedures were less frequently required in the yoga group. Coronary angiography repeated at one year showed that significantly more lesions regressed and less lesions progressed in the yoga group.”

To have such a profound effect on the largest cause of death in the West makes me believe this should be mandatory for companies to implement for their staff. The downstream effect on the economy from less healthcare costs, etc. is also worth noting.

Fortunately, another study measured heart rate variability and blood pressure during chanting. “Both prayer and mantra caused striking, powerful, and synchronous increases in existing cardiovascular rhythms. Baroreflex sensitivity also increased significantly.” Baroreflex sensitivity refers to the body’s ability to control blood pressure, a parameter highly associated with cardiovascular disease. Heart rate variability (cardiovascular rhythms) is associated with positive mood and reduced anxiety levels, which we will now explore further.

Neurological

Our neurology is the least understood system of the human body. Every day we discover something new about how our brain and it’s chemicals work. Despite this, the research describing the benefits of yoga predominantly involve our nervous system. What’s undeniable for any experienced practitioner of yoga, is the feeling we have after practice.

The effects of yoga on the neurological system are profound. From balancing neurotransmitters to increased levels of grey matter. From changes in brain waves to permanent physical rewiring as a result of neuroplasticity, our brains are an incredible organ that allows us to feel the full spectrum of emotions, something very unique to the human species.

Our major stress hormone cortisol directly destroys neurons in our hippocampus, which leads to a poor ability to integrate short term memory to long term memory. When we meditate, we gain a much greater control of our HPA-axis, which governs cortisol secretion. This act of meditation undoubtedly leads to greater memory and concentration through the attenuation of the sympathetic nervous system. As for our Limbic system, it not only regulates our emotion but is also the centre for autonomic breath control. This is why we may experience a release of emotions during intense sessions of pranayama.

Brain waves are the result of and control our state of being in the world. We have 6 activity levels of brain waves, measured in hertz (cycles per second):

  1. Gamma 38-42hz
  2. Beta 12-38hz
  3. Alpha 8-12hz
  4. Theta 3-8hz
  5. Delta 0.5-3hz
  6. Infra-Low <0.5hz

As Steven Cope suggest in his book The Wisdom of Yoga, brain waves can be altered through the practice of yoga.

“Brain wave activity begins to shift from the “beta waves” of regular wakefulness to somewhat longer, slower “alpha waves”. We feel what it’s like to inhabit a truly calm body. New research shows, too, that meditation produces identifiable changes in the brain. Meditation increases activity in areas of the brain associated with positive feelings, reduction in anxiety and faster recovery after negative provocation.”

Copeexpands further

“We know that [meditation] promotes states of equanimity in several ways: The levels of stress hormones – epinephrine, norepinpherine, cortisol – are ratcheted down, calming the nervous system. Heart rate and blood pressure drop and the breathing rate slows as the body’s need for oxygen is reduced. Metabolism slows. Muscle tension is relaxed significantly.”

All of this is achieved through the activation of the parasympathetic nervous system. When we practice meditation, chanting and diaphragmatic breathing, we activate the vagus nerve, which is responsible for the ‘rest and digest’ functions of our body.

Yoga also effects our neurotransmitters. Through deep breathing, we can produce dopamine, which stimulates our reward centres of our brain. This suggests that yoga could potentially have a positive effect on people suffering from addiction. The calming effects of yoga are very noticeable. Part of this reason is the increase in production of GABA, a neurotransmitter that governs our feeling of calmness as well as our ability to sleep for 8 hours unbroken throughout the night.

It’s clear that yoga positively affects our neurophysiology, which as we will now see, results in greater feelings of happiness as we navigate this wonderful thing called life.

Mood & Spirit

Suicide is the largest cause of death in Australian men under the age of 50. This statistic is very disturbing for anyone who has gone through depression and knows what it means. Yoga played a major role for myself eliminating depression. The main area of our brain that governs fear and anxiety is the amygdala. It’s been shown that meditation can actually reduce the activity andsize of the amygdala after just a few weeks of beginning.

One study involving depressed men of military service said:

“Subjects who participated in the yoga course demonstrated significant decreases in self-reported symptoms of depression and trait anxiety. Changes were also observed in acute mood, with subjects reporting decreased levels of negative mood and fatigue. Finally, there was a trend for higher morning cortisol levels compared to the control.”

The effects are equally positive for healthy women:

“The yoga group showed markedly higher scores in life satisfaction and lower scores in excitability, aggressiveness, openness, emotionality and somatic complaints. Significant differences could also be observed concerning coping with stress and the mood at the end of the experiment. The yoga group had significant higher scores in high spirits and extravertedness.”

It’s been suggested by various teachers that yoga and meditation allows us to tap into deeper levels of creativity and awareness. Cope wrote poetically in his book:

“Concentrated states [of awareness] give us access to the right hemisphere of the brain, which is the sphere of symbols, dreams and archetypes – where a special quality of nonrational, nonlinear wisdom resides. Loss of linear sense of time. Distortions in the proprioceptive sense of the body. The body may seem to get very large, very small, or parts of it disappear altogether.”

These states of awareness are associated with permanent changes in areas of the brain that enhance equanimity. By practicing yoga we can experience these profound shifts in happiness, awareness, neurological health and creativity.

Immunity

Yoga has been developed to enhance the feelings of wellbeing experienced by the mind but also to strengthen the resilience of the body. Somehow, yogis explored their internal physiology so deeply that they began to understand the raw power that it can display.

I have written previously about my encounter with the Dutch man Wim Hof and his breathing techniques. After spending 5 weeks at an ashram in the foothills of the Himalayas, I understood that Wim had adapted his techniques from the yogic tradition.

Wim’s philosophy is that the spectrum of human existence in geographical terms would have forced some of us to march across arid deserts and others over frozen lakes. Through these desperate climates, our physiology evolved to withstand these extreme environments. Yes, they would have used different clothes and shelter, but the survivors of these tough times may have developed complex breathing and meditation techniques to withstand these climates. It is only through our comfortable modern lifestyle that we have forgotten that we are capable of such feats of resilience.

Wim is fortunate to have the following of Western Science behind him as recent journal articles have come from Europe detailing Wim’s incredible ability to control his immune response to the injection of E. coli toxin lipopolysaccharide (LPS). Wim, and his 10 students who learned the technique over 4 days were able to suppress the symptoms of the toxin, while the control group suffered from intense fevers for hours.

The Wim Hof Method (WHM) has been helping sufferers of severe allergies, autoimmune conditions and chronic inflammatory diseases like arthritis. These incredible results are due to the breathing techniques controlling immune regulatory cytokines. Pro-inflammatory cytokines, TNF-α, IL-6, and IL-8, are significantly lower in people performing WHM, while anti-inflammatory cytokine IL-10 and epinephrine are increased rapidly during “intermittent respiratory alkalosis”. The researchers conclude “we demonstrate that voluntary activation of the sympathetic nervous system results in epinephrine release and subsequent suppression of the innate immune response in humans in vivo. These results could have important implications for the treatment of conditions associated with excessive or persistent inflammation, such as autoimmune diseases.”

Other studies outside of WHM, in typical Hatha Yoga practice, have demonstrated increased levels of antioxidant enzymes & glutathione activity and also an enhanced regulation of white blood cells. From this, we can make the assumption that we are less likely to get sick from the common cold and suffer from chronic illness. It is evident, yoga and it’s associated practices have an incredible effect on the body’s immune system and tolerance of extreme environments.

Respiration

It probably doesn’t come as a surprise that something that focuses so heavily on breathing could enhance your respiratory system. But to dive into some of the how’s is still interesting. In yoga, there is a focus to lengthen and deepen the breath rather than using short, shallow breaths like we do when lifting heavy weights. The focus is on expansion and softness, rather than tension and tightness.

The many ways yogis breathe.

  • Abdominal breathing
  • 3 Part Yogic Breath
  • Anuloma Viloma (Alternate nostril breathing)
  • Kapalabhati (Shining Skull Breath)
  • Kumbhaka (Breath retention)
  • Bhastrika (Bellows Breath)
  • Brahmaree (Humming)
  • Ujayi (Conquerer’s breath)
  • Chandra bhedi (Lunar breathing)
  • Surya bhedi (Solar breathing)

Pranayama is a Sanskrit word we use for breath work that means life force without restraint. Yogi’s believe that breath is life and the way in which we use our breath can dictate so much about the way we navigate through this world. If it is short and fast, our mind is quick and agitated; If it is deep and slow, the mind is calm and content. There are a few simple explanations for this. Firstly, when our diaphragm contracts and pushes our abdominal organs down and out, this triggers our major parasympathetic nerve, the Vagus nerve. The parasympathetic nervous system (PNS) comprises of our rest and digest facilities, making us calm and relaxed. Secondly, when we breathe deep we deliver more oxygen to the tissues throughout the body and in particular, the brain. When the brain has oxygen, we are happy.

Another way yogi’s increase oxygen delivery is, counter-intuitively, by holding the breath. The Bohr Effect says that when carbon dioxide levels rise in the blood, there is a faster delivery of oxygen from the blood into the surrounding tissues. To capitalise on this, we breathe a lot for a short period (1-5 minutes), then hold the breath. After increasing oxygen levels, we increase carbon dioxide and force more oxygen out of the bloodstream and into the tissues. Side note: To trigger the PNS, we hold the breath out; To trigger the sympathetic nervous system, we hold the breath in.

By drawing out the exhalation, we also feel a deeper sense of relaxation through the PNS. This is one of the reasons we perform Ujjayi breath throughout the class. Yes, it sounds like the ocean, or Darth Vader, which is nice, but this foundational technique is used to create presence, focus and calmness throughout the entire yoga practice. If you don’t do it because it feels silly or uncomfortable, I highly encourage you to go all out for just one class and notice if you feel any different. Another way of drawing out the exhalation is by humming. Brahmaree pranayama is used to soften the mind and muscles through the release of nitric oxide. We breathe in deeply and hum like a honey bee for as long as we comfortably can. In more advanced practices, we can hum for the entire class. It’s a trip!

Through breathing techniques, we can strengthen the breathing muscles, namely the diaphragm and intercostal muscles, which can allow us to breathe deeper and easier at rest. If you have ever felt short of breath or tight in the chest due to stress or even anxiety, you have lost full control over your respiratory muscles… you have lost control of your life. Get back in control by first focusing on the breath. Practice these techniques until I tell you to stop.

Digestion

According to Dr Mario Martinez, author and longevity scientist, 75% of busy executives have gastrointestinal disorders. You don’t need me to tell you that’s a lot. What is the likely link? Stress.

Your central nervous system interacts with another nervous system located in your gut: The enteric nervous system. Yep, your gut pretty much has its own brain. You have experienced this connection before – those butterflies in your stomach are caused by an emotional response. To separate the mind and body would be ridiculous.

Cortisol affects the gut in many ways.

  • Decreased nutrient absorption
  • Decreased oxygenation of the gut
  • Reduced blood flow – as much as 400% less
  • Reduced enzymatic output – as much as 20,000 fold

A chronic elevation of our primary stress hormone, cortisol has been linked with many chronic gastrointestinal disorders. Crohn’s disease, IBS, Ulcerative colitis, Bowel cancers to name a few. Stress affects the gut in many ways, including disruption of bacteria & gut hormones and increasing intestinal permeability (leaky gut).

How then does yoga prevent this damage from occurring? By interrupting it at the source. By affecting the neurochemistry, we affect the gut chemistry. This does not mean we can eat a whole pile of gluten, sugar, alcohol and conventional dairy products. With a healthy diet, yoga can help alleviate many chronic digestive conditions. I know from experience, whenever I’m more stressed, my guts don’t function as well.

If you’re taking care of your nutrition, pay attention here. A simple yoga practice incorporating backbends, forward bends, twisting and side-bending, coupled with breathing and meditation could be the answer to your unhappy guts.

I have explored nearly the entire human body and its relationship with the ancient practice of yoga. The research doesn’t stop here. As the West aligns more and more with the East, studies will continue to pop up and prove that what was developed thousands of years ago may be all we need to be happy, healthy and strong.

I hope that what I’ve illustrated is reason enough to practice yoga. With the reduction of many of the largest killers in the Western World as well as the increase in feelings of happiness and general life satisfaction, it is evident to me that yoga should be a lifelong practice for most people. I wonder if the entire world could maintain a regular yoga practice, what kind of place it would be.

References:

  • Cope, S. The wisdom of yoga: A seekers guide to extraordinary living. (2007). Bantam Publishing.
  • The Art of Living. The Science behind Yoga (n.d.). Retrieved from http://www.artofliving.org/yoga/yoga-for-beginners/science-behind-yoga
  • Woolery, A., Myers, H., Sternlieb, B., Zeltzer, L. A yoga intervention for young adults with elevated symptoms of depression. Alternative Therapies in Health and Medicine10.2 (Mar/Apr 2004): 60-3. Retrieved from http://crawl.prod.proquest.com.s3.amazonaws.com/fpcache/344413c890b7f879f2e9bd0d71586c18.pdf?AWSAccessKeyId=AKIAJF7V7KNV2KKY2NUQ&Expires=1476610487&Signature=6hDqV%2F2MjfaBq6Bu%2BcDdC5rlsz0%3D
  • Manchanda S.C., Narang R., Reddy K.S.,Sachdeva U., Prabhakaran D., Dharmanand S., Rajani M.,Bijlani R. (2000). Retardation of coronary atherosclerosis with yoga lifestyle intervention. The Journal of the Association of Physicians of India 48(7):687-694
  • Bernardi L., Sleight P.,BandinelliG.,Cencetti, S.,et al. (2001). Effect of rosary prayer and yoga mantras on autonomic cardiovascular rhythms: Comparative study. British Medical Journal, International edition. 1446-9.
  • School F.J., Allolio B., Schonecke O.W. (1994). Physiological and psychological effects of Hatha-Yoga exercise in healthy women. International Journal of Psychosomatics : Official Publication of the International Psychosomatics Institute 41(1-4) 46-52
  • What are brainwaves? (n.d.). Retrieved from http://www.brainworksneurotherapy.com/what-are-brainwaves
  • Sanchari S., Som N.S., Monga Y.P., Uday S.R. (2007). Improvement of Glutathione and Total Antioxidant Status with Yoga. The Journal of Alternative and Complementary Medicine. Vol. 13, No. 10: 1085-1090
  • Koxa M., Van Eijka L., Zwaage J., Van den Wildenberga J., Fred C. Sweepd G.J, Van der Hoevena J.G., Pickkersa P. (2013). Voluntary activation of the sympathetic nervous system and attenuation of the innate immune response in humans. Proceedings of the National Academy of Sciences of the USA. Retrieved from http://www.pnas.org/cgi/doi/10.1073/pnas.1322174111