The Science of Yoga

I recently listened to an interesting podcast on Dr. Mark Hyman’s Broken Brain series about the science of yoga. This was a rather long podcast but it made a yoga believer out of me. Eddie Stern is a yoga teacher and author and he recently published his book, One Simple Thing: A New Look at the Science of Yoga and How It Can Transform Your Life. Yoga has been used for centuries for improving physical and mental health but how exactly does yoga do this? And how does yoga work?

Here are some of the highlights:

  • The author highlighted several studies conducted on the efficacy of yoga. One involved 68 participants and they found that sleeping diastolic blood pressure dropped by 4 points with an average drop of 7 points for both diastolic and systolic. In another study with middle school students, the yoga protocol raised grade point averages by 2.7% with 40 weeks of yoga vs. 40 weeks of a gym program. Yoga impacts the nervous system and the ability to have focused attention is dependent on the nervous system. We teach children how to tie shoelaces but not how to pay attention. Yoga works by down-regulating the sympathetic nervous system (sympathetic releases adrenaline and norepinephrine which will impair your ability to have focused attention, strategic planning) and also tones the vagus nerve.
  • What is the vagus nerve? It is the tenth and longest cranial nerve inside our body and controls many functions. The vagus nerve is 80% of the parasympathetic nervous system which is responsible for rest, digestion, repair and restoration. Also, 80% of the vagus nerves travel from our visceral organs up to the brain and deliver the message on what’s happening to the lower parts of the body. Only 20% of the vagus nerves work in the reverse direction which tells the body what to do. So that partly explains how yoga body movements and rhythmic breathing work – it sends messages to the brain that the body is being paid attention to and effectively tones the vagus nerve.
  • What is yoga’s role? According to the author, all religious traditions have had neural exercises that tone the vagus nerve which can reduce inflammation of body and mind, and decrease risk of diseases like cardiovascular, cancers, diabetes and digestive disorders. The four limbs of yoga include posture, breathing, vocalization and behavior.
    • Posture ­– proper posture and sitting straight tones the vagus nerve
    • Vocalization – chanting or breathing with sound stimulates the vagus nerve to down-regulate the sympathetic system
    • Rhythmic breathing – movements of the diaphragm send signals to the vagus nerve that everything is calm and balanced
    • Behavior – kindness, appreciation and gratitude will strengthen the vague nerve and reduce heart rate variability. Other behavior elements include honesty, not causing harm, not stealing, sexual responsibility and not coveting things we don’t have/need.
  • The context of yoga is that we can find safety in our body and nervous system to heal. We have the ability to self-regulate and self-soothe to deal with anger and frustration. Our mind and body is a continuum and there is no distinction; for example, thinking is a physical process just as movement is. There is no distinction between thought and how it affects our body. If we are depressed, it shows in our physical body – we are hunched over and our face is drawn. Our emotions and thoughts are expressed through the body. Yoga reconnects the bifurcation of body and mind by starting with the body. It starts with the brain stem to regulate breathing and to re-engage the pre-frontal cortex to bypass the sympathetic response so we can make a choice and not be controlled. Hence, through yoga, we are using our body to access the mind.
  • Our brain processes thought and movement so the way our body is moved influences our mind. When we influence our thought process, we influence our perceptions which is key when dealing with stress. Stress perceptions are not all bad – we need stress to build resiliency in our nervous system and for growth. The perception we have about stress will help us determine how we deal with the challenge vs. a struggle. Resiliency comes from addressing challenges and managing stress and this happens when there is a nice integration of flow of information between the body, the brain and the processing of the stress perception.
  • Trauma is not stored in the brain but in our body, so talk therapy is good but yoga and other modalities can help determine where the trauma is stored so one can start to work on it and build resiliency to support the nervous system.
  • What is the purpose of yoga? Yoga is about calming the fluctuations of our field of awareness. Our awareness is clouded by thoughts; we identify positive and negative thoughts and they hide us from our true self. Yoga is the process of selectively eliminating all the different movements or thoughts in the field of our awareness that are counter to who we really are.
  • Yoga addresses relaxation, moving the body, breathing, being present and practicing appreciation for the abilities we have. There are many different types of yoga but they all work. Yoga provides stress level reduction, improved concentration, better state of well-being and mind, better physical health, and more sensitivity to diet and nutrition.
  • Resonance breathing is between 5-7X per minute vs. a normal 15-18X per minute. Through resonance breathing, we are halving the cycle of respiration and through this, the heart rate variability and blood pressure all come into the same coherent pattern. This pattern resets the nervous system balance mechanism, improves heart rate variability, vagul tone and reduces inflammation. For example, when we are meditating, our breathing shifts into this resonance mode. By doing resonance breathing, we are essentially going into a meditative state without actually meditating. The resonance breathing is at 0.1Hz per minute which is the delta wave brain state that is the same as being in deep sleep without dreaming. So it’s the most restful state we can be in and we are conscious while doing it. According to the author, resonance breathing is the single most effective practice.
  • The author has a great free breathing app on the app store (The Breathing App by Eddie Stern). This app includes timers and sounds to breathe with – along with an inflating/deflating ball to match breathing rhythm. It’s awesome – try it!

If you are up to listening to a 96-minute podcast, click on the link below for more details:

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