- The following post was written for Symmetry by one of our recent Doctoral Resident Students – Catherine Madsen – from the Texas State Physical Therapy Graduate Program. Catherine is a yoga instructor as well as a long-time yoga practitioner. Thanks for your insight, Catherine!
What is yoga?
The practice of yoga has been around for thousands of years and has recently experienced a surge in popularity in the West. Many gyms, corporate offices, spas, and medical practices have started offering yoga classes as a compliment to their other services. Then there are of course yoga studios popping up on every corner providing a variety of class types, ranging from vinyasa to hatha to kundalini to ashtanga. But let’s not get into the weeds here… the important thing is that all of these different types of yoga originated from the same sacred text, The Bhagavad Gita. This ‘bible of yoga’ is actually a poem that is set on a battlefield and teaches the reader about love, happiness, peace and how to manage the ‘battlefield of the mind’. During these ancient times when the Bhagavad Gita was written, there was only one yoga pose – lotus pose, also known as sitting cross-legged. This posture was meant to be practiced while meditating and even today remains a staple of many yoga classes. The physical practice of yoga has evolved substantially since then, and unfortunately this has resulted in many misconceptions about yoga. You do not need to be a certain age or size to practice yoga, nor do you have to be flexible or strong. Yoga is for everyone and the poses themselves are still beneficial when modified to work for your individual body. Each pose, or asana, works the following body systems:
- Musculoskeletal – in the various yoga positions you are bearing weight through your joints and using your muscles to hold each pose
- Respiratory – yoga instructors emphasize deep breathing while holding poses and may even incorporate specific breathing techniques during mediation to help circulate fresh oxygen throughout the body
- Nervous – when poses are practiced in a sequence, their cumulative effect results in a decrease in the activity of our ‘fight or flight’ nervous system, resulting in less stress and anxiety
Let’s delve more into the function of the nervous system, the stress response, and what ‘nervy’ means in relation to musculoskeletal pain.
The Nervous System:
The nervous system has 2 divisions: central and peripheral. The central nervous system (CNS) consists of the brain and spinal cord, whereas the peripheral nervous system (PNS) includes everything else. One component of the PNS is the autonomic nervous system, which involuntarily controls our internal organs and regulates things like heart rate, blood flow, breathing, and digestion. The autonomic nervous system itself has 2 of its own divisions: sympathetic and parasympathetic. These two systems essentially perform opposite functions. If the sympathetic nervous system stimulates a response, the parasympathetic nervous system will work to inhibit or decrease that response. Both systems work together to manage the body’s response to the environment. These are the divisions we are going to focus on.
The sympathetic nervous system (SNS) is often referred to as our ‘fight or flight’ system. When we are faced with a threat or stressful situation, the SNS will get the body quickly ready to take action. This includes increasing the heart rate, pumping blood away from the organs (stomach, intestines) and into the muscles, increasing breathing rate, and releasing a shot of glucose into the bloodstream for a quick burst of energy. These changes prepare us to effectively respond to the threat that is presented. While in the midst of a stressful or dangerous situation, we are often not aware of these changes. However, once the situation has resolved we may notice our fast-beating heart or mildly upset tummy. These feelings are a result of the actions of the SNS. This system is designed to be active for only short amounts of time. For example, if you were to burn your hand on the stove, your SNS acts quickly to signal you to move your hand away from the heat. However, recent studies have shown that more and more people are in a chronic state of sympathetic activation due to stress. When the SNS is active, cortisol, or the stress hormone, is released, which perpetuates the ‘fight or flight’ cycle. Being in near constant ‘fight or flight’ mode can result in impaired digestion, elevated blood glucose levels, and impaired immune system activity. In addition, constant SNS activation can result in increased sensitivity of the entire nervous system, which manifests as ‘nervy’ symptoms in the arms, hands, legs or feet. Nerves do not communicate sensitivity via a typical pain signal, when they are irritated, it may like feel like numbness, tingling, burning, stinging, buzzing, etc. These ‘nervy’ symptoms, though they often present in the extremities, can be a result of an overactive sympathetic nervous system, which is located close to the spine. Other symptoms of an overactive SNS might include things like headaches, restlessness, anxiety, or difficulty sleeping.
The parasympathetic nervous system (PNS) is often referred to as our ‘rest and digest’ system. After a stressful event, this system should kick in and return the body to its resting state, also known as homeostasis. The PNS system works slower than the SNS, which is one reason why we may still feel stressed for a period of time even after a threatening situation has resolved. As stated earlier, the PNS is responsible for the opposite actions of the SNS. When it is active, heart rate and breathing should be normal and relatively slow, blood is shunted to the stomach and intestines to stimulate digestion, and emotions should be calm and regulated. Proper functioning of the PNS is integral to healing, sleep, and restoration.
How Yoga Soothes the Nervous System:
The word yoga comes from the root ‘yuj’ which means ‘to yoke’ or ‘to unite’. Each individual who practices yoga has a different idea of what yoga unites exactly, but generally, most practitioners will attest that yoga unites the mind, body, and breath. The soothing environment, dim lighting, and calming music of a yoga class also contribute to a general relaxing effect. This in combination with the performance of a sequence of poses that strengthen the connection of muscles to nerves results in decreased activity of the ‘fight or flight’ system and increased activation of the ‘rest and digest’ system. Another way that yoga soothes the nervous system is through pranayama or breathing techniques. Throughout a yoga class, you will hear breathing cues from the instructor as they encourage coordinated movement of breath and body. Research has shown that simply becoming aware that you are breathing will increase activity of the PNS.
The PNS can be likened to the depths of the oceans and their stillness, while the SNS is like the waves and storms on the surface of the waters. It is easy to get wrapped up in the storms of daily life and become stuck in a rut of sympathetic activity. Yoga helps to teach us that the waves and storms are inevitable but not indefinite and there is a wealth of calmness within us that we can activate at any minute by simply using our breath. Namaste!