The Physiology of Yoga

    Breath: The Incognito Master of Balance


Have you ever been struggling for balance in the middle of class, with your foot burning and eyes shifting, as your teacher delivers the cue, “Don’t forget to breathe!” In the midst of your frustration whilst trying not to topple over in natarajasana (dancer pose), you’ve probably formed a (silent) rebuttal along the lines of “Of course I’m breathing! It’s my darn leg that’s the problem!” While it is indeed very likely that you’re experiencing muscular fatigue in your leg, the breathing cue nonetheless carries more weight than you might think.

Many yogis are probably already familiar with some of the philosophy 10463728_10100192994948456_7742401807369315323_o(from both a spiritual and physiologic standpoint) behind the importance of breath in yoga practice. The breath, or manifestation of prana (which translates as “life force”), is a powerful tool that can be utilized to both calm and ignite the mind and body. By focusing on the breath, we are able to take a vacation from the constant chatter in our minds, as well as to activate the parasympathetic nervous system (more on this in a later post) to bring our physiologic processes into a more restorative state. While these are important aspects of breathing, they still overlook the role that the actual act of breathing can have on our balance.

On a macro scale, the act of breathing has been shown to influence our postural sway. As we breathe, our chest cavity expands and retracts rhythmically, slightly shifting our center of mass. Our bodies then compensate for this shift by adopting a slight sway. Several studies (1,2) have demonstrated that an increased rate of breath results in increased postural sway, a compensatory mechanism that maintains balance. Therefore, by slowing down and controlling our breath as we do in yoga, we shift our center of mass less often and thus decrease our postural sway.
Balance is controlled on a micro scale in our bodies as well. While there are several factors that play a role in this, a central player, known as the vestibular system, is located inside the ear. The vestibular system is a series of fluid-filled canals that control the way we perceive and orient ourselves in space. Intricately connected to the brain via a cranial nerve, the shifting of the fluid of the vestibular system lies in close proximity to the Eustachian tube, a small canal made up of both bone and cartilaginous material that connects the nasal cavities to the ear.

The influence of the Eustachian tube on the vestibular system and our sense of balance has been highlighted in several scenarios. In one study (3), Eustachian tube injury was linked to the development of vertigo in SCUBA divers. Similarly, another study (4) identified patients with Meniere’s disease (a disease which causes periodic episodes of vertigo) had decreased Eustachian tube function when compared to healthy individuals. While these studies are observatory and do not offer a physiologic explanation as to why Eustachian tube defect and balance are related, investigation into the anatomy of the nasal and ear cavities provides a logical explanation, as the proximity of these two structures allows for interaction between the systems. When we practice deep, slow breathing (especially
ear-anatomyujjayi breathing which constricts the back of the throat, shunting air towards the nasopharynx cavity) we are able to generate a pressure gradient which can travel from the nasopharynx cavity, down the Eustachian tube to the ear, and thus exert a pressure on the outside of the semicircular canals, providing some stabilization to the fluid inside. This stabilization prevents random, rapid motion of the fluid and has a subtle effect on the brain, resulting in a more stable and balanced neural input from the cranial nerve to the brain’s balance centers. 

A useful visual of this system is to imagine a half-filled plastic water bottle. If this water bottle is placed on its side on a counter and shaken, the fluid in the water bottle will move rapidly from side to side because of the pressure difference the water and air inside the bottle create.  However, if this water bottle is submerged underwater in a bathtub and then subjected to the same disturbance, the fluid inside will shift around less violently because the external pressure generated by the water in the tub provides a stabilizing, inward pressure on the bottle. This system also exists in our bodies, with the breath exerting an external pressure on the middle and inner ear to stabilize our vestibular system.

To bring this back to the mat: When we are struggling in natarajasana, frantically shifting our hips back and forth, that deep breath just might help incite a subtle change that will settle our bodies and minds. While the breath has other profound effects and the vestibular system is not the only physiologic process that affects our sense of balance, the application of mindful breath as a means of steadying the vestibular system can be utilized to help us in our yoga practice.

So go ahead and take a nice, deep inhale—that breath will help in more ways than you think.

For more information about Jessica, please scroll down to the previous post, or visit her bio HERE. 

References 
1. Kitajima N, Sugita-Kitajima A, Kitajima S. Altered Eustachian Tube Function in SCUBA Divers  
    with Alternobaric Vertigo. Otology and Neurotology 2014; 35 (5): 850-856
2. Park JJH, Luedeke I, Luecke K, et al. Eustachian tube function in patients with inner ear
    disorders. European Archives of Otto-Rhino-Laryngology 2013; 270 (5): 1615-1621.
3. Hunter IW, Kearney IE. Respiratory Components of Human Postural Sway. Neuroscience
    Letters 1981; 25(2):155-159
4. Byung YJ. Respiration effect on Standing Balance. Archives of Physical Medicine and
    Rehabilitation 1991; 27(9):642-645

The Physiology of Yoga

Hi all!

While I already know many of you from working behind the desk for the past year, I would like to officially introduce myself as a new manager at Coolidge Corner Yoga. I am thrilled for the opportunity to become more involved with this awesome community of people that has come together in an effort to “feel good, do good.”

In addition to my role as manager, I will be utilizing my academic and athletic background to create a new blog component to the CCY website,  The Physiology of Yoga. To give you an idea of where I’m coming from, I have trained as a physiologist for the past nine years, working in a variety of different settings. I completed a bachelor’s degree in biochemistry, minoring in sports medicine, at Pepperdine University in 2010. While obtaining my degree, I was involved in research investigating how the body controls the
jessica
return of blood from the peripheral circulation to the heart. Following graduation, I had the privilege of working with a psychiatrist, helping to grow and administer a new therapy program for patients suffering from depression, anxiety, and other psychiatric illnesses. After helping establish this program, I moved to San Diego, where I earned a Master’s degree in exercise physiology from San Diego State University. There, my focus was on the biochemistry of both exercise and nutrition. During this time, I was lucky enough to conduct research on the effects of several styles of military training, as well as to produce a novel paper on the effects of Bikram Yoga on new and experienced practitioners. After completing this work, I realized I wanted to pursue an even deeper understanding of the human body, so I moved to Boston to complete a second Master’s degree in human physiology at Boston University. During this time, I expanded my knowledge in several realms of basic science while gaining a greater understanding of how airway smooth muscle and vascular smooth muscle physiologically respond to various life stressors.

I have also been an athlete my entire life. I started swimming at age seven, trained with a national team at the US Olympic Training Center in Colorado Springs during high school, and went on to swim for a NCAA Division I team in college. During this time, I was able to learn from some of the top trainers and nutritionists in the country. Training at this high intensity for over a decade provided me with a complementary, experiential education, which allowed me to begin drawing connections between my academic and athletic backgrounds.

However, it was not until I took up a consistent yoga practice in college that I truly began to see the deep, interconnected nature of my athletic and academic training . From the moment I stepped into my first class, I knew yoga would be an influential force throughout my life. During class, I would find myself repeatedly making connections with what I was learning in the academic realm to things that would surface, both physically and mentally, during my practice. These connections solidified my belief in the power that a yoga practice can have on our lives. I have developed a passion for raising awareness and understanding of how our bodies and minds can benefit from yoga and the yogic lifestyle. Undoubtedly, there is a wealth of information on the positive outcomes that can result from yoga. However, sometimes this information can be lost  on the general public because of the overwhelming body of literature and overuse of scientific jargon. I hope to utilize my broad scientific knowledge base to condense and interpret the existing literature into “bite-sized” portions for the CCY community, as well as offer new perspectives on how our physiology relates to our yoga practice.

The Physiology of Yoga  will feature original content on a variety of topics including the physiology of yoga, kinesiology, nutrition, mindful living, and much more. I look forward to contributing to the knowledge CCY has to offer and am always open to suggestions if there is a particular topic you would like to see highlighted. I am here to translate the science behind issues that are directly impacting our community.

Namaste.

-Jessica Pate