The easiest way to understand this difficult subject is to picture our central nervous system as a building with a lot of electrical wires. The wires don’t do a whole lot, but plug in a television, and for some people, their entire world has miraculously changed. Plug-in a washing machine and we have a totally different function. Nothing is happening in the house until the appliances (muscles, organs, glands) are turned on.
Sensory receptors are like switches that turn on the body. A sensory receptor can be as simple as a raw nerve ending that tells us we’re being burned, to something as complicated as a retina that allows us to convert reflections of light into images. Nothing is going to take place in the body without these switches being stimulated into the ‘on’ position.
Ninety percent of the incoming sensory impulses to the brain come from the joints and muscles. That’s why contracting muscles and moving joints have a profound effect on all neurological function, which then affects every other system in the body. Mostly, it happens in two special areas of the brain- the hypothalamus and the brain stem – the starting points for most of the automatic functions of the body. Included here are blood pressure, heart rate, sweating, control of blood vessels, eye motion, function of the digestive system, temperature, balance, and muscle coordination.
Muscle and joint receptors communicate with higher brain centers so that the body can function. One example is, your heart wouldn’t know to speed up to pump more fuel, nor would your blood vessels know to contract in some areas and open up in others in order to shunt that fuel to the muscles that are being used and require it, and away from your stomach which doesn’t need a whole bunch of blood in it when say, running from a saber tooth tiger. These very old reflexes that we are born with are meditated between the spinal cord and the brain. Everything occurring in our bodies needs to be controlled by our brains. A dysfunction in one area or system can wreak havoc in another. An example of this that you might be able to relate to is our thyroids could be producing all the thyroid hormone we need, but if our livers can’t convert it into the useful form that circulates in our blood we could end up with a prescription for thyroid hormone which we already have plenty of. I have seen many patients with a painful syndrome known as reflex sympathetic dystrophy. They complain that their hands feel like they’re burning. Typically there is nothing wrong with their hands. Quite often a spinal segment that controls the blood vessels that nourish the hands is not firing properly and the hands don’t receive the blood they need. Less oxygen causes pain nerve endings to fire. The more pain signals the more spasm to blood vessels creating a vicious syndrome.
If the joints don’t move properly, the brain doesn’t receive correct sensory input, resulting in diminished to no output to the muscles. This decrease in output affects the protein in the muscles that perform work. These proteins resemble velcro. The velcro (muscle) will lose its binding ability in just six days if it doesn’t receive signals from the joints. Think about an arm in a cast. When the cast is removed, not only have the muscles atrophied and bone density decreased, but also the skin has become dry and scaly. That’s because the oil glands aren’t firing due to a lack of sensory signals from the joint.
That was a very bold statement- glands not working because of faulty joint movement. All functions of the body depend on joint movement and since we’re talking about yoga and stretching muscles, it’s our muscles that move our joints. It is important to fire the receptors in both joints and muscles, and I know of no better system than yoga to do this.
When joint receptors don’t fire, because of nonuse, it’s as if the brain has no idea that part exists; so, it withers and dies. Again, the arm in the cast is not moving, the mechanoreceptors in the elbow haven’t been stimulated to fire, so why send protein to a region that is not there and low and behold when your arm is taken out of the cast, it’s skinnier than the other one. The Russian Cosmonauts that were in space for a number of years lost so much protein in their spinal muscles, that they are still incapacitated to this day. They exercised, but it wasn’t enough. It’s as if they were in whole body casts, because of the lack of gravity.
That 90% of information our brain receives from our joints and muscles I mentioned at the beginning needs gravity to respond maximally. When we appeared on the earth, there wasn’t always light or a Mozart concerto to stimulate our brains. The only one constant stimulus we can depend upon is gravity. So our brains get charged and recharged by gravity. The most ancient systems in our body lie in the middle of it. Our eyes and ears are connected to midline spinal cord and brain stem structures, which coordinate us. Typically when we hear a loud noise behind us, we turn our head and eyes together to focus on what might be creeping up on us. We can do this because these muscles are coordinated by the vestibular and cerebellar parts of our brain which function because of gravity. The vestibular tracts also fire down the spinal cord to the intrinsic muscles of the spine, which automatically hold us up in earth’s gravitational field.
The point of all this is what made us human is gravity. Our cerebellums are larger in proportion to our brain comparatively to other species because we stand on two legs and we need very complicated equipment to perform this taken for granted task. One thing that will help keep us human is resisting gravity aka yoga. My best argument for this is Joe the teenage couch potato; sitting there all day playing video games. Not a week doesn’t go by without the media reporting that our children are sicker than ever before. Of course eating man made chewing devices sold in the food isles is the bigger reason our kids have developed diseases that were unheard of a few decades ago, but when we are firing our nervous systems optimally, which is accomplished when performing yoga, our digestive systems could probably manage to incinerate practically anything we threw down there although, I don’t recommend it. To make this even simpler, it’s not the weight you lift that is as important as the movement of it. But Dr. Malakoff my back hurts, I can’t exercise.
This seems a good as time as any to examine the typical low back patient. This person is bent at the waist. Their flexor muscles (abdominals) are overpowering their extensors (back muscles). If the flexors were weak, they would be bent backwards. Keep in mind extensor muscles should always be stronger than the opposing flexor group. These deep low back intrinsic extensor muscles are antigravity muscles, regulated by a part of the brain that acts like an automatic pilot. Otherwise, we would lose our minds having to constantly think about how to oppose gravity. This part of the brain is called the cerebellum and is fired up by, you already know this, muscles and joints. The significance here is, if you can’t control a muscle group, then how do you exercise it? You can turn your hand, but let me see you rotate your bottom vertebrae to the left, while moving the one above it to the right. Don’t try it for too long, because you just can’t do it. It’s these deep intrinsic spinal muscles also known these days as core stabilizers, that we can’t control, that are often the cause of low back pain.
So, when patients tell me that their doctors advised them to do sit ups to solve this problem, I find myself bewildered. You can exercise the large muscles but how can you exercise a muscle that you have no volitional control over? The answer is you can’t. What makes even less sense from this advice is, why strengthen your abdominal flexor muscles with sit-ups when your spinal extensor muscles need to be stronger. The good news is, these deep low back muscles do receive signals that are summated from different areas of the body not associated with the low back, hence the need to work your whole body. As a chiropractor I have to gloat and smirk over that last comment because up until very recently we were considered crazy dangerous lunatics. Actually some people still think of us this way but, now thanks to the decade of the brain, which was 1990, modern science has discovered that we were right all along. But before there were chiropractors, there were yogis and I consider that they somehow knew this stuff thousands of years ago to be one of the truly great wonders of the world.
One reason Tiger Woods is beating the old guys on the golf course is because he has more sensory receptors. We naturally lose populations of these receptors with age. You see this all the time. People in their sixties typically have to spread their legs further apart when standing to keep their balance. Often they lose their hearing. Without these receptors less sensory information comes in and we have decreased performance often in areas we would never associate with the musculo-skeletal system as being the problem. These receptors also allow for fluid movements. When a joint moves uncontrolled because the sensory receptors around it are no longer firing properly, the joint breaks down its cartilage. Cartilage is made of long sugar protein, the favorite food of white blood cells. When exposed, cartilage attracts white blood cells and the inflammation process begins. Reduced movement also increases inflammation by allowing pain signals to increase. When this happens, we either move less or take drugs, which cause many different types of damage (arthritis, kidney and liver failure, digestive disorders, etc.). Drugs such as aspirin, Tylenol, Advil, and Motrin allow joints to degenerate painlessly, while they continue to kill the receptors in the joint, causing a vicious cycle.
Reduced activity adversely affects the brain stem too. When we don’t move joints and muscles the amount of electrical signals being transmitted from those receptors is less. Fewer movement signals allows pain signals to increase. As pain signals come into the cord, they cause muscles to go into spasm, which decreases our desire to move further still. When the vagus, a nerve that controls the heart, respiratory, and digestive functions, isn’t receiving proper signals, a myriad of symptoms results. This nerve has connections to the organs in the body and when it transmits a signal that has become corrupted because it received the wrong information from our environment via sensory receptors that are not working right it can mimic disease, so be aware. A whole bunch of problems can occur with our bodies and the pharmaceutical companies have dangerous solutions for every symptom you might experience. Actually these days most of the symptoms we’re experiencing are from the drugs we are taking. Right now Viagra is one of the biggest selling drugs. But most people need it because they’re on heart medication. But if these people would exercise they’d probably have better hearts. Since they don’t have good hearts I question the wisdom of taking a pill that is going to force them to have marathon sex. I’m sorry, I’ll try and stick to the subject.
In spite of our artificially created inability to believe we could ever be healthy, human beings are equipped to overcome these problems naturally. The machinery just has to be used correctly or, at least, just used. I think, at this point, you should be convinced that practicing yoga is probably the best health insurance you can buy. One word of cautionary advice, muscles attach to bones and perform work by moving across a joint. Joints especially spinal joints, should be functioning optimally. I don’t feel it is wise to train muscles with joints that are sending out incorrect signals to our central nervous system. A chiropractor’s job is to discover which sensory receptors are not working optimally, typically because of poor spinal joint mechanics and restore them to normal function. Once our machinery is working right I recommend yoga to everyone to keep it working optimally.