Bandha Yoga Scientific Keys to Unlock the Practice of Yoga

Posted by Anonymous to The Daily Bandha at February 19, 2011 6:24 AM

Many people do not consider is the neurophysiological and neurocardiological implications of expanding anatomy principally used as accessory muscles in breathing, especially if these muscles are then used more often in regular breathing outside of specific pranayama practice. There are stretch receptors in and around the intercostals that feed to receptors in the brain and nuclei of the solitary tract and paraventricular nuclei within the hypothalamus that control breathing. Furthermore, repeated or habitual thoracic breathing can overstimulate stretch receptors within the right atrium, leading to cases of increased heart rate (tachicardia) and possible hypertension. Please think carefully and beyond just anatomical considerations when considering using practices that affect the neurological, homeostatic and cardiorespiratory systems.

Kind regards and many Oms
(Consulting Neurophysiologist)

Posted by DailyBandha to The Daily Bandha at February 19, 2011 11:42 PM

Hello Anon Consulting Neurophysiologist,

Your comments warrant a closer look. There are most certainly sensory receptors in the chest wall that communicate with the brain--there are sensory receptors all over the body that are stimulated when we move.These connections probably help explain why incorporating the accessory muscles of breathing into pranayama enhances the effects, such as calming the mind etc. Accordingly, I will continue to advocate using these muscles in yoga.

In regards to your comment on repeated or habitual thoracic breathing overstimulating right atrial stretch receptors (and somehow leading to hypertension), can you point to any published article supporting your statement? I do not find any on Pubmed. This doesn't surprise me because stimulating atrial stretch receptors causes a decrease in ADH, which lowers blood pressure. Evidence based physiology directly contradicts your statement that it raises blood pressure (hypertension). Think about it: when the right atrium senses high filling pressure, it's receptors, inter alia, signal the neurohypophysis to decrease the production of antidiuretic hormone (ADH). This leads to increased urine output (diuresis), lowering circulatory volume and eventually lowering blood pressure. If you were actually a real life neurophysiologist (read: advanced university degree in neurophysiology), you would have learned this in your first semester physiology class. Then you might be able to "think beyond anatomical considerations"--and wouldn't have to embarrass yourself by anonymously posting erroneous material in your role as a consulting neurophysiologist.

Increased venous return to the heart (right atrium) during deep inhalation is a natural phenomenon, due to the negative pressure produced when you take a deep breath. When venous return increases, this stimulates the stretch receptors in the right atrium, so that it responds by emptying into the right ventricle—part of homeostasis. You see this during exercise. Temporary fluctuations in heart rate including increases during inhalation are seen in highly trained athletes. This is generally considered to be a beneficial response.

Sleep apnea (stopping breathing during sleep) is an example of a pathological breathing condition. It raises blood pressure and has other adverse effects on the cardiovascular system. Apnea is the opposite of deep breathing. Deep breathing is good for you.

In this regard, I suggest you take a read through these publications, which also go over the physiology of breathing and its effects on the cardiovascular system:

Grossman E, Grossman A, Schein MH, Zimlichman R, Gavish B. “Breathing Control Lowers Blood Pressure”: J Hum Hypertens. 2001 Apr;15(4):263-9.

Pinheiro, C. H., and R. A. Medeiros, et al. “Spontaneous Respiratory Modulation Improves Cardiovascular Control in Essential Hypertension”. Arq Bras Cardiol. June.88 (2007): 651-59.

These may help you to fill in some of the gaps in your comprehension of physiology. In the meantime, please tell me what evidence you have that “thoracic breathing” causes some pathological condition? What is the neurophysiological mechanism for your theory?

Obviously, one must proceed carefully with any yoga techniques including pranayama. I don't recommend overdoing it with any powerful technique.

Hope this helps clarify things,

Ray Long, MD FRCSC