We’ve all felt many kinds of pain—from cuts and scrapes to headaches to sore muscles. Each of these types of pain emits a unique signal (or set of signals) that is transmitted throughout the body. Yet one of the distinctive things about pain is that it can’t be objectively measured—our primary means of studying pain is through our own subjective experience.
This subjectivity of experience has mystified pain researchers for decades, and has made it tremendously difficult to accurately diagnose, let alone cure, pain. But recent groundbreaking studies on the function of our body’s connective tissue may hold the answers to why we all have such varied experiences of pain—and how we can heal it.
Pain Follows Many Paths
One thing we do know: Pain is experienced through the nervous system. Our peripheral nerves stretch from the spinal cord to the muscles, bones, joints, organs, and skin. On the very end of our nerve fibers are a specific type of receptors, called nociceptors, which make up an early-warning system that sounds the alarm when we experience tissue damage—or even when we experience potential tissue damage.
When the nociceptors sense something that could cause harm—such as the hot stove that your hand just brushed—they send electrical impulses along your peripheral nerves to your spinal cord and brain. Those nerves release neurotransmitters that communicate the pain message farther along the channel, all the way up to the thalamus in your brain.
Once the message arrives, the thalamus—an oval mass of gray matter in the middle of the brain—then passes it along to three other areas of your brain:
The somatosensory cortex, which tells you where and how intensely you feel the pain.
The limbic system, which tells you how you experience the pain emotionally.
The frontal cortex, which tells you how to process the pain intellectually.
In each of these areas, the pain message is specific to the individual experiencing it. Depending on your body’s unique release of neurotransmitters and your current state of health—including preexisting injuries and baseline inflammation levels—the pain message might be amplified or quieted down at any point in the communication chain. Other variables, too, influence how you experience the pain message, including your current emotional state, memories of pain you’ve experienced in the past, or your determination to “grin and bear it.” All of these mental and emotional messages can influence the way you feel pain—and they all can happen simultaneously, in a split second.
In the case of chronic pain, pain messages that were once simple can get stuck in a rut. Like a needle caught in a groove of a vinyl album, pain messages can start skipping and replaying endlessly in a “pain loop.” Instead of heading in a singular direction—from nociceptors to peripheral nerves to spinal cord to brain—these pain messages hit the spinal cord and then the neurotransmitters just explode, branching off in all directions at once. One of their targets is glial cells.
Making up most of the brain’s connective tissue, glial cells were originally presumed to function like nervous system putty—glia comes from the Greek word for “glue.” For decades, scientists thought glial cells were simple structures that held together the higher-functioning elements of the nervous system. But new research has revealed that glial cells are incredibly active in almost every aspect of nervous system function, including:
Brain development
Homeostasis
Information processing, learning, and memory
Formation of myelin (the protective sheaths around nerves)
Regeneration of certain neurons
Glial cells, it turns out, play a key role in how we experience our senses—and our pain. They can lessen our pain, make it worse, or even distort it completely. Once glial cells are activated by the original neurotransmitter release, their DNA synthesizes new proteins, which spill out of the cell membranes and interact with other glial cells around them. Depending on the message being transmitted, those other cells may then release their own neurotransmitters, whose DNA synthesizes their own proteins and spill out again. As this chain continues, the pain loop is reinforced, becoming stronger and more distorted. The original pain signal becomes just a tiny part of what you experience—instead, each time the pain loop is triggered, you’re also feeling the echoes of past pain messages, which can get stronger and stronger, depending on the degree of feedback.
In a TED talk from March 2011, Dr. Elliot Krane, a professor of anesthesiology at Stanford Medical School, described this pain feedback loop and likened it to the work of a rogue electrician who has sneaked into your house and rewired all of your circuits so that the next time you flip a light switch, your toilet flushes or your computer turns on. The rewiring completely distorts the subjective experience of pain and may leave it quite far from the original source of the pain. At this point, the distortion becomes a disease in itself: the scourge of chronic pain.1
Chronic pain can be incredibly tenacious, and it becomes more entrenched with every trigger. This chain reaction is part of what makes healing from pain so difficult—and why pain medications are woefully inadequate and unequal to the task. Certain pain relievers might temporarily mute the pain signals, and others might tamp down the inflammation so that the body is not as primed for pain—but unless you can reprogram the pain transmission itself, you cannot disrupt the pain loop.
Is it possible to reprogram the transmission? Possible, but challenging. Unfortunately, we can’t just send in a little scavenger to scoop up all the misfiring glial cells and get rid of our rogue electrician. Some researchers, like Dr. Krane, are investigating drugs that can be used to target the glial cells directly. But what seems to be most effective is to use nature’s own remedy, which turns out to be a more basic, mechanical, and long-term solution: gentle exercise.
HOW ARE INFLAMMATION AND PAIN LINKED?
The most commonly used pain relievers actually don’t directly target pain itself—instead, they target inflammation. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, acetaminophen, and even the humble aspirin, try to stop the inflammatory cascade from even starting. Inflammation is triggered when the body is trying to fight something—bacteria, viruses, injury, or, in the case of autoimmunity, our own body tissues. To fight the foreign substances, the body releases white blood cells, which increase blood flow and swelling in the affected area. But while this is meant as a protective process, the resulting swelling and excess inflammatory substances can irritate the nerves, exacerbate pressure on the joints, and lead to serious damage.
Exercise is one way we can attempt to communicate with the misfit cells and persuade them to stand down and stop transmitting (and duplicating) all those extra pain messages. That could be because exercise can directly manipulate glial cells’ connective tissue cousins—the sheets and bands of fascia that move and stretch throughout the body.
Connective Tissue: The Missing Link
As we’ve discussed, until recently scientists viewed the musculoskeletal system as a workhorse—responsible for posture and movement, and not much else. But a new field of research is finally helping to prove what has long been understood by practitioners in disciplines like traditional Chinese medicine and physical therapy: that the musculoskeletal system has a wide-ranging influence on all bodily systems.
In a line of research that spans more than twenty years, pioneering researcher Dr. Helene Langevin has suggested that our fascia functions as a “living matrix.” Her research offers evidence that this connective tissue is in a constant state of communication—with itself, with other parts of the body, and with the outside world—helping coordinate and regulate the activities of many major bodily systems. As Dr. Langevin stated in her groundbreaking 2006 paper in the journal Medical Hypotheses, “Since connective tissue is intimately associated with all other tissues (e.g., lungs, intestine), connective tissue signaling may coherently influence (and be influenced by) the normal or pathological function of a wide variety of organ systems.”
Dr. Langevin described the wide-ranging role of connective tissue in The Scientist in 2013:
[Connective tissue] joins your thigh to your calf; your hand to your arm; your breastbone to your clavicle. As you move, it allows your muscles to glide past one another. It acts like a net suspending your organs and a high-tech adhesive holding your cells in place while relaying messages between them. Connective tissue is one of the most integral components of the human machine. Indeed, one could draw a line between any two points of the body via a path of connective tissue. This network is so extensive and ubiquitous that if we were to lose every organ, muscle, bone, nerve, and blood vessel in our bodies, we would still maintain the same shape: our “connective-tissue body.”2
Thankfully, after decades of neglect, more researchers—including those interested in the therapeutic applications of exercise programs like Essentrics—are focused on exploring the healing potential of our connective tissue. The hope is that we can discover new ways to silence the ever-present signaling of chronic pain and get back to living full, pain-free lives.
The Function of Fascia
When you look at most anatomy books, you’ll see drawings of bones and ligaments, tendons and muscles, but you’ll rarely see the whitish or semi-translucent bands and sheets that are involved in most muscular movements—the fascia (or, to use the plural, the fasciae). Fascia has traditionally been known as an uninterrupted, three-dimensional web that surrounds and interpenetrates muscles, groups of muscles, blood vessels, and nerves, binding some structures together while permitting others to slide smoothly over each other.3 However, researchers are now debating new theories about the function of our fascia.
The existence of these tight-fitting lubricated sleeves enables the nerves, muscles, and all other human tissue to stretch or shrink as we move, and then return to their original shape with total ease. These sleeves are one reason why we maintain our shape as we reach, bend, crunch, and extend our body throughout the passage of a day.
You’ve probably never given a second thought as to why your body looks the same in the evening as it did in the morning. Since moving creates a kneading action on our soft tissue, we could easily change shape every day—but we don’t! Why is that? The fasciae encase all our tissues, giving them a limited, lubricated area in which to move. And as we stretch or contract our muscles continuously, the fasciae allow those movements—indeed, they love them!—but always return to their original starting shape.
When we raise an arm, the muscle cells must slide to permit the lengthening of a muscle; the nerves embedded within the muscles must also be able to slide, and the tendons must slide back within their sheaths. This intricate dance occurs each time we do something as simple as throwing a ball to a dog or waving hello to a friend.
Also essential to movement is the fluid within the fascia, which is actually liquid, or “gel-like” connective tissue. (I referred to this in my first book as the body’s “oily bath.”) This liquid nourishes our tissue and prevents its various components from adhering to one another; without this critical lubrication, our cells become glued together, making us feel stiff.
Immobility is one of the most common causes of pain because it leads to the solidifying or hardening of this liquid connective tissue. Every time we move, we create a subtle pumping motion that gently pushes fluid through our living matrix. Immobility permits the fluid to congeal; as it does so, the tissue layers become somewhat sticky. That’s why when our movement is restricted over a prolonged period—such as when we recover from a surgery or an injury—we start to feel very stiff and sore.
If connective tissue is the integrating matrix for the whole body, you can see how congested and glued tissues might start to become a serious issue. What kinds of terrible biological missteps might develop if we had massive logjams of adhesion right in the middle of our fasciae? You’ve likely heard the saying massage therapists often use: “You’ve got issues in your tissues.” Until we release those knots and blocks in our fasciae, we may be preventing all kinds of critical physiological communication from getting through.
Dr. Langevin’s research clearly shows that our connective tissue relays different types of messages, including electrical, cellular, and tissue remodeling signals. Each of these signals then creates patterns that interact with one another and evolve over time. By this theory, if there is a blockage in our connective tissue, pain messages could be magnified in loops, tissue repair messages could be blocked, and even signals of pleasure or relaxation might be hampered or blunted.
Just imagine how much better we could all feel if our bodies had none of those blockages—and our connective tissue was able to facilitate open and direct communication with all of our major organs. The good news is, that’s entirely possible. These messages can be manipulated by simple changes in our movements and posture.
Given the emerging science of connective tissue and what I’ve learned from helping people suffering from chronic pain, I know the Essentrics program works to improve the natural integrity and healing power of connective tissue—thereby improving all the communication that’s taking place, moment by moment, within our living matrix.