- Hello! The Complete Guide to Yin Yoga … is lovely, however, before I praise you, I'd like to get to the point of this email: on page 36 you write "Our edges are always changing, and today may be quite different than yesterday. Our bodies change. Some days we retain more water in our tissues than other days. Water retention affects our flexibility." I was wondering if you could explain this as we were all stumped. My only thought is that more water in our cells leads to plumper cells/tissues which would lend itself to less freedom of movement. Now, onto the praise portion of my email. As a voracious reader with not a lot of free time on my hands, I nowadays doubly appreciate a well written and engaging book and yours is exactly that. It is clear, concise, accessible and entertaining to boot. Namaste, Evelynn.
Thanks for your question. In another book of mine (Your Body, Your Yoga) I talk more about water. To explain and hopefully answer your questions, I am extracting some of the paragraphs from that book. Let me know if you still have questions.
WATER: You have probably heard that we are 60% water. That is an average—the range of values is quite broad and differs signicantly by gender. One study found that in a group of 18 men and 11 women, the water content varied from 46% to 70%. The average for the men was 62%, but the average for the women was only 52%! This gender variation is due in part to the fact that fat contains less water than other tissues, and women have more fatty deposits than men.
We are mostly walking bags of water. Our ground substance is the nonfibrous portion of our extracellular matrix (the stuff outside the cells of our bodies) in which the living cells are held in place. e ground substance is made up of various proteins, water, and glycosaminoglycans. Water can make up 60% to 70% of the ground substance, and it is attracted there because of the glycosaminoglycans. One of the most important glycosaminoglycans is hyaluronic acid (also known as hyaluronan). The fluid in our joints (called synovial fluid) is a lubricant that is also made up substantially of glycosaminoglycans—predominantly hyaluronic acid, lubricin and two kinds of chondroitin sulphates. Various researchers have estimated that hyaluronic acid can attract and bind 1,000 times its volume of water. When glycosaminoglycans combine with proteins, they are called proteoglycans, and it is in this form that they attach to water molecules and hydrate our tissues. The proteoglycans are very mobile and move about freely. However, being made of water, they also tremendously resist compression. e proteoglycans are shaped like brushes connected in tree-like arrangements, and they wind their way through the collagen fibers of our fascia and cartilage. Our tissues can swell if too much water is absorbed by the glycosaminoglycans, but the tissue fibers resist and limit the amount of swelling that can occur. It is this interplay between the swelling of our tissues and the resistance of the fibers that creates tension and structure. is arrangement also is responsible for the ability of our articular cartilage to withstand repetitive forces.
THE WONDER OF WATER
Water is sticky and loves to cling to surfaces. This is not so obvious in our macroscopic everyday world, but as we start to investigate the role of water within and between our cells, this fact becomes very obvious and very important. We call this stickiness surface tension. No doubt you have seen bugs that walk on water; this is due to surface tension. As small as these Jesus-bugs are, our cells are vastly smaller and much more susceptible to water’s stickiness. As a layer of water becomes thinner, the surface tension increases, and therefore so does its stickiness. Water is also highly incompressible. When stress is applied to a bag of water, the water doesn’t compress; instead, the tension is distributed throughout the bag. is phenomenon is known as hydraulics (which literally means “water in a pipe”) and is used in everyday machines to amplify and distribute pressure—for example, in your car’s hydraulic brakes. The final main point to know about water is that, within the body, it is structured: it forms layers upon layers that cling to each other, much like a bowl of gelatin. This gel state of water can also add tensile resistance to movements within and between cells. The other state of water found within the body and within cells is the solution state, when the water is in a more unstructured, bulk form and is free to flow and move around.
If you have ever had two pieces of flat glass laid on top of each other—perhaps you were preparing slides for a microscope—you may have noticed that with just a little bit of water between the two glass plates, they slid quite easily but were almost impossible to pull apart. You’ll notice the same effect when you walk upon sand at the beach. Walk on dry sand, and your feet sink in, but walk on wet sand, and you don’t sink—you are walking on water! The surface tension of the water glues the sand particles together, and these small particles of sand can now support your full body weight. Thus, water can lubricate our tissues, allowing gliding movements as with the glass slides, and water can bond our tissues together, creating rigidity and support, like the wet sand at the beach. How this happens is fascinating but beyond our scope of our investigation. What we can investigate are the consequences of these facts about water, because it is the major component of the body’s ground substance.
With water as its principal component, the ground substance is an excellent lubricant between fibers and fibrils, allowing them to slide freely past each other. Water gives our tissues a spring-like quality, permitting them to return to their original shapes once pressure has ceased. This is crucial to our tissues’ ability to withstand stresses; however, a cyclical loading and unloading of the tissue, which we do in our yoga practice, is important for maintaining cellular health
When the extracellular matrix is well hydrated, cells, nutrients and other components of the matrix can move about freely. Toxins and waste products can be escorted out of the matrix into the lymphatic system and removed from the body. The ground substance, produced by the fibroblasts, is also helpful in resisting the spread of infection and is part of our immune system barrier.
Unfortunately, as we age, the body’s ability to create water-loving proteins that keep our tissues wet (called glycosaminoglycans) diminishes. We have fewer fibroblasts available to us, and those we do have produce fewer glycosaminoglycans. Consequently, the extracellular matrix is increasingly filled with more and more fibers. As these fibers come closer together, they generate cross-links that bind them to each other. Our tissues thereby become stiffer, less elastic and less open to the flow of the other components in our matrix. Toxins and waste products are trapped in the matrix and cannot get out, and harmful bacteria can multiply freely. Immobility is one big cause of steep losses in hydration; immobilization can cause an up to 40% loss of hyaluronic acid—our most common glycosaminoglycan—in our joints, reducing the amount of water we have there and the ability of our tissues to slide across each other.
What stops me? Well, one thing that makes us stiffer is a lack of water in the extracellular matrix. Without this lubricant between our tissues, we get stuck. However, if we have too much water, we can also become stiffer, just as a tube that is full of water is less flexible than an empty tube. Many women notice how their flexibility varies considerably throughout their menstrual cycle; this corresponds to the amount of water they retain at various times of the month. If they are retaining too much water, stiffness and restricted mobility result. When we suffer too much inflammation, we similarly have too much water in our tissues, which reduces our mobility.
Fortunately, exercise like yoga and massage, which stresses the extracellular matrix, can help us maintain the number of fibroblasts we have and keep them functioning properly, which assists in hydrating our extracellular matrix and our joints. These forms of exercise also allow the state of water to periodically change, from gel to sol and from sol to gel, which is important for the healthy functioning of our cells.