Yoga, The Nervous System, and The Spine

At the request of some of our yoga students I am writing an entry about the nervous system, how it relates to the curves of the spine, and how we can affect it through conscious exercises such as yoga. 

Nerves are bands of fibrous tissue that carry messages throughout our bodies. They are much like the wiring in a computer. They are just as real and palpable as blood vessels, muscles, and organs. Because nerves are a physical structure they can be affected by tight muscles, injuries, and unhealthy posture. Nerve roots are the part of a nerve that exits the spinal cord between two vertebra before it travels out to the rest of the body. They are the place where the two parts of our nervous system communicate.

A compressed nerve root refers to an actual squeezing of the nerve as it comes out from between two vertebra on its way to the rest of the body. If you squeeze a hose that has water running through it the water flow will be impeded and pressure will build up. The same thing happens in our nerves where the nerve is the hose and the water is the impulses that carry messages back and forth between the brain and the body.

Our central nervous system (CNS) is comprised of the brain and spinal cord. Our peripheral nervous system (PNS) is comprised of all the nerves that run throughout the rest of our bodies. These two nervous systems communicate with one another via the nerve roots mentioned previously.

There are two branches within the peripheral nervous system. They are the Sympathetic branch and the Parasympathetic branch. Each of the branches holds an opposite function and our body is constantly adjusting how much each branch is activated. 

The sympathetic branch is responsible for the 'fight or flight' response. This system is activated in times of stress and danger and leads to adrenaline being released, heart and breath rates to quicken, the pupils to dilate, and blood flow to increase. The parasympathetic branch is responsible for the 'rest and digest' response. This system is activated in times of low stress. It leads to blood moving to the organs, the heart and breath rates to slow down, and an overall sense of relaxation and restfulness.

Problems occur when one of the branches is overly stimulated for an extended period of time. Because of our culture, jobs, and life structure, Americans tend towards having their Sympathetic branch chronically stimulated. This leads to health issues such as anxiety, chronic stress, weight gain, tight muscles, headache, low immune system function, difficulty sleeping, and high blood pressure among others. In order to balance this a two-part solution must take place. The first is to lower the function of the Sympathetic branch and the second is to stimulate more activity of the Parasympathetic branch.

There are many ways we can affect the branches of the peripheral nervous system. Because the peripheral nervous system starts in the spine at the junction between the vertebrae we can affect it by adjusting the spine. Chiropractic care is an example of how this approach can be employed. 

Alternatively we can send signals from other areas of the body back to the roots of the nerves to tell the body to calm down. Acupuncture is a good example of this method. Because there are different approaches it is important to make use of the different healthcare modalities available to us and integrate them together to receive the most effective care.

We can also engage our bodies and nervous systems on our own without the assistance of someone else. This is an important approach to take as well because it empowers us in our bodies and in our lives. It makes receiving other treatments more effective, longer lasting, and ultimately puts us at a place of power in our own lives. Yoga is a way of using this approach to health.

Before we talk about specific yoga alignment let's take a closer look at the spine. The human spine is comprised of roughly thirty two bones. There are four curves in the spine. Two of them are concave and two of them are convex. Bones are connected to other bones by ligaments and to muscles by tendons. Between all the layers of muscle there are additional layers of connective tissue that hold everything together. Misalignments in the body can be due to bones, muscles, or connective tissue. The spinal cord runs through the center of the bones of the spine and, along with the nerve roots, are affected in shape and functionality by the posture of the spine.

Many systems of yoga and other exercise use alignment based on old research that showed that accentuating the natural curves in the spine lead to injuries in the spine and nerves whereas making the back flat, tucking everything under, and taking the curves out of the spine lead to greater stability. 

There are several problems with these studies. The first is that since these studies have been accepted and used as the basis for healthy alignment in our body no one has researched other possible alternatives. For over sixty years we've accepted that those studies discovered everything we needed to find about proper alignment in the spine. Secondly, the studies looked at overarching the lower back. What they didn't look at was the method in which the back was arched. Simply put, the back can be arched either by collapsing into it and compressing the vertebrae or by engaging the muscles of the legs to create a deep but spacious curve in the low back that matches the spine's natural alignment. Lastly, the studies all looked at arched backs where the last thoracic vertebrae (T12) in the middle of the spine poked out. None of the studies looked at alignment where T12 moved in and up, which only happens when the spine is arched through muscular engagement.

When the curves are taken out of the spine it causes the nerve roots to become compressed and sends signals to the brain that the Sympathetic branch needs to be activated. When the natural curves are put back in the spine it signals the brain to activate the Parasympathetic nervous system.

Our Sympathetic activation is exacerbated by the large amount of time that people spend sitting at desks. Sitting this way leads to several problems. It takes the natural curve out of the low back, it takes the natural curve out of the neck and when the chin is lowered it pulls on all the muscles in the jaw, neck, and upper shoulders, and, finally it tightens our hips and groins which also stimulates the Sympathetic branch. This also causes the bones of the legs and arms to be pushed forward out of their sockets. 

Tucking under requires the engagement of the butt muscles from the top of the butt to the bottom of it. This engages the muscles from the insertion to the origin. We engage every other muscle in our body in the opposite way - from the origin to the insertion. Why would it be that one of the strongest muscles in our body should be the only one that should be engaged opposite from all the other muscles? In the new system of alignment the butt muscles are engaged from the origin to the insertion (bottom to top) which naturally creates a deep spacious curve in the lower back as a result.

If an exercise class is using an old system of alignment it is basically creating the same posture we end up in sitting at desks and in cars. We end up creating the same problems we're trying to fix. The new system of alignment reverses these tendencies and reintroduces the natural curves back into the spine. Some basics of the new system of alignment I use in my teaching are:

1) Make the legs strong

2) Use this strength to create a spacious, deep arch in the low back until T12 moves in and up

3) Allow the upper back to soften and the ribs to move towards the ground

4) Look up and make the curve in the neck match the lower back

5) Extend the whole body in both directions from T12

Here is another way of looking at it:

When an animal is afraid or upset they round their lower back and neck, and tuck their tail between their legs. This is the same action of "tucking the tailbone" under that we have all been instructed to do in the past. This is an example of what animals do when they are in Sympathetic dominance. Another example is a cat arching its back when it hisses at something.

 

When an animal is relaxed and at ease and has just woken up from a nap it takes a nice big stretch as seen here. The lower back is rounded, the groins are soft, the hips are pressing back, and the chin is lifted to create a curve in the neck.

Here are more photo comparisons:

In the first set of photos we can see the difference between the old and new styles of alignment. The bottom picture shows a rounded spine, rounded neck (though usually the rounding is even more severe), and and overall look of unease. The top photo shows strong legs creating a natural arch in the lower back and the chin lifted to create a matching curve in the neck. The shoulders are lifted and the ribside is extended.

The second set of photos shows the new alignment and how it matches with the way animals align their bodies in a stretch. In the top photo I could have even more bend in my knees so as to lengthen the spine and extend the hips back more. Notice how overall the arches of the spine and alignment of the shoulders and hips match up.

 

The new system of alignment activates the Parasympathetic nervous system while at the same time strengthening and toning the body. Because the spine is naturally curved the nerve roots have the least amount of pressure put on them when the spine is in its natural alignment. By putting the spine in this alignment and then using our muscles to lengthen the curves it creates space between the vertebrae which takes pressure off the nerve roots, thus sending a message to the brain to activate the parasympathetic nervous system. Less obstruction and compression on the nerves creates feelings of ease and restfulness.

When the natural curves of the spine are supported by clear engagement of the muscles and healthy alignment of the limbs there is more than enough stability to support the curves. Old systems of alignment try to take the curves out of the spine because it is believed that the hyper-mobility of the lower back and neck are too unstable and easily injured. This assessment is only true if there is no muscular engagement supporting the arches in these parts of the spine. 

Finally, when we allow the ribcage to descend towards the ground we allow gravity to gently pull on all the connective tissue surrounding our internal organs. When we surrender in this way it further activates the Parasympathetic branch. This isn't to say that the abdominal muscles aren't engaged. They are, but instead of contracting and shortening them we engage them while they stay long and extended. 

These are some basics of the way our nervous system works in conjunction with our anatomy and alignment. There are many different systems of exercise and alignment available and it's good to explore many different ones in a safe way so that you can become more empowered in your own body. Following, I've included more pictures for comparison.

~Joshuah Ciafardone, L.Ac

The new method of alignment is from the Sridaiva system of yoga developed by Desi Springer and John Friend.