Sensing
If you are a regular participant at Transformations Studio you will hear the terms “sense” as applied to a particular structure of the human form. In classes we might say “sense” where the bottom tip of your scapula is in relationship to the ribcage, is it wider than the ribcage or behind the ribcage? I would like to simplify what is meant when we use the term “sense” this way. There are many different definitions for the verb sense. To sense can mean to “perceive by the sense or senses, to be aware, to observe”. We are using the term “sense” interchangeably with the idea of observing or noticing. So when we suggest that you “sense” something, we are suggesting that you bring your conscious awareness to the area by observing or noticing the space. I would like to clarify for you, however, the difference between sensing, as it applies to the activity of the body of receiving information to the brain via the sensory nerves and observing/noticing.
Sensing in the body is not a conscious activity. Sensing occurs when information travels along the sensory nerve pathways in the body and the information reaches the brain. The sensory information travels from the body into the brain without our consciousness or control. The nerve signal that is sent to the brain is a binary one, meaning that it is the same signal being sent all of the time. The consistency of signaling lulls the brain into an impression of stability and safe-keeping. The same signal is being sent from the nerve when a joint is opening or closing. The same signal is being sent from the nerve when fascia is hydrated or not hydrated. The same signal is being sent from the nerve when a muscle we have is a “sore muscle” or we don’t notice the muscle at all. When your back hurts and when it doesn’t hurt, the nerve sends the same signal to the brain!!!!!! The only true difference in the signal to the brain when we “feel” our back hurting is its rate of speed. When our consciousness becomes aware of a sensory signal, the nerve signal has changed volume. There is a greater number of stimuli in a shorter period of time causing the nerve to be stimulated enough to reach the nerve threshold. As the nerve reaches its nerve threshold this triggers a change of rate of speed of the sensory signal. This speed change of the nerve signal is novel and therefore gets the brain’s conscious awareness. In order for us to be consciously aware of anything new in our body there has to be enough change in the volume of the input of the nerve signal to get our brain’s attention that something is different. Normally the novelty of the change of input would trigger the attention of our conscious brain in order to help us update the brain map for efficiency of movement, or to react appropriately to the signal to ensure the body’s health and well-being.
What Can We Actually Sense?
Most of us are familiar with the basic senses – sight, smell, taste, touch, and hearing but currently science has discovered that the brain receives information from the body about these 19 different senses.
Sight/Light
Infrared
Ultraviolet Light
Cosmic Rays
Electromagnetic (EMF) waves
Airbourne Ionic changes
Atmospheric pressure
Magnetic Orientation
Vestibular – Inner sense of equilibrium
Balance and Movement (Proprioception)
Smell
Taste
Sound
Gravity Awareness
Object Orientation (how near or far something is)
Wet or Dry
Air currents
External Temperature
Contact Pressure (Touch)
Let me bring your attention to a few items that are not on the list above.
We do not have a sense of our muscles being tight or loose, weak or strong or contracted or relaxed. This is because muscle tissue primarily consists of motor nerves, nerves which deliver information from the brain to the muscles to stimulate movement or change of position. Sensory nerves that are located in the muscle are called muscle spindles. Wikipedia defines muscle spindles as “sensory receptors within the belly of a muscle that primarily detect changes in the length of this muscle. They convey length information to the central nervous system via sensory neurons.” The ratio of sensory to motor nerves in the different muscles varies. In small muscles used for fine motor control, for example muscles around the eyes and fingers, we have a greater number of muscle spindles (sensory nerve receptors). Larger muscles that are responsible for gross motor movement and posture have a smaller number of sensory nerve receptors in them. This is demonstrated in the photo below of the body. The body parts that are the largest have the greatest number of sensory nerves.
If we were able to sense our muscles well, simply based on the amount of sensory nerves we have in an area, we would have a terrific sense and awareness of our eye muscles, lips, tongue, hand and finger muscles. To this date, I have yet to hear anyone complain of a tight, long or short eye muscle. I have also never heard anyone say my finger muscles are sore and tight, yet complaints about the tight hamstrings, back or neck muscles are a regular occurrence.
We do not have a sense of our body’s weight. Weight is a comparative point of reference. If I were to have you close your eyes and hand you a weighted ball and ask you to tell me how much it weighs, you would have to recall experiences in your past to base your decision on. If I handed you two more balls and asked you to put them in order of weight from lightest to heaviest you would be able to attempt to do so based on comparing the three balls. You could tell from many different senses in your hand, including touch and gravity awareness (when one ball is in your hand, it takes more to keep your hand from dropping to the floor) which ball might be the heaviest and which ball might be the lightest. People commonly describe their bodies using the idea of weight. “I am un-even, there is more weight on the right side of the body on the floor than the left side of the body on the floor.” We make these statements based on comparing how one side feels perceptually in relationship to the other. In this instance, what we might really be noticing is the surface contact on the floor via touch, how much of the right side of my body touches the floor verses how much of the left side of my body touches the floor. When more surface contact is touching on one side we then sometimes make the association that there is more weight on the floor. This is a faulty association, what the reality is, is that there is more of my body touching the floor on one side than the other.
We do not have a sense of our own internal pressure. We often speak of the body’s valve system and its function of regulating internal pressure. Internal pressure is defined as pressure “situated within, affecting, or relating to the inside of the body”. Pressure can be created by fluid or air. A few examples of areas in the body where fluid pressure exists are blood pressure in the arteries, veins and capillaries, aqueous humor in the eye, gastrointestinal fluid and cerebrospinal fluid in the brain. Some areas in the body where air pressure exists are the middle ear, the sinus cavities, the intrathoracic space, inside the lungs and the intra-abdominal space. Functionally the internal pressure of the body changes on a moment to moment basis in response to the external environment. Upon laying down on something hard the internal pressure of the body should increase in order to prevent the hard surface from compressing the body structure. In picking up a very heavy weight the internal pressure would be different in the body than if picking up a pencil. Sitting on a hard stool would trigger a different internal pressure than sitting on a soft couch. The internal pressure in the body is constantly changing. This would cause a constant stimulation of the nerve threshold and therefore constantly be getting our conscious brain’s attention. There are many things in the body that are constantly changing i.e. blood circulation, hormone flow, etc. We do not receive sensory nerve information to the brain about these constantly changing variables because our conscious brain would be so distracted with all of the novel information. With all of that sensory input distraction it would be challenging just to carry on a conversation with anyone.
We do not have a sense of “feeling”. We do not have a sense of feeling in the body. Oftentimes the word “feel” or “feeling” is used to label a perception that we have about a change in the body or an emotional state of mind. I have heard many different ways that individuals have described how they viewed their bodies that were all related to a sense of feeling. Here are a few descriptors;
This feels relaxed.
This feels like it is working hard to be in this position. This feels like my body is resisting me. This feels stiff. This feels unbalanced. My body feels anxious.
We do have a sense of Contact Pressure – otherwise known as touch. The sense of contact pressure tells us when a part of our body is in contact with another physical surface. It also alerts us to when the contact against the physical surface changes. When you first get into bed and get under the covers we consciously notice where the covers touch our body. Over time the novelty of the signals wears off and we are not aware of the covers connection to our body anymore. It is part of the status quo. But then the family cat or dog decides to join us in bed and they lay down on our stomach. Suddenly we are aware of a new contact pressure on our body, we are aware that something has changed :)
Takeaway:
Remember that sensing occurs unconsciously. When we do become consciously aware of new sensations in the body; it is an indication of physical change. Something in the body has changed enough to stimulate the nerve to its nerve threshold so that the rate of speed of nerve signaling to the brain has changed. The body is trying to get the brain’s attention so that it can most appropriately adapt to the change. Once we are aware of the sensation we have two choices as to how to deal with it. We can observe the location from which it is coming from or we can attach some meaning to the sensation.
