Resilient Bodies: How Your Tissues Adapt to Stress
Many of the people I see in my practice underestimate just how phenomenal our bodies are in the way of adapting to physical challenges. Too often, especially when we are experiencing pain or a loss of function, we underestimate our body's innate ability to adapt and recover. For many physiotherapy patients, the bulk of their treatment plan is simple: graduated exposure of injured tissues or painful regions to controlled amounts of stress, or small progressive challenges to promote tissue healing and adaptation.
The Blister vs. the Callus
Consider this: imagine you just beginning to play the guitar. If you were to practice too much all at once, your fingertips would form blisters and eventually even start to bleed (here’s to you, Bryan Adams). However, if you started out playing just a few minutes a day, and then increased the duration of your practice over a longer period, you would form calluses and be able to play for long periods with ease. This transformation from blister to callus is a testament to our body's remarkable ability to respond and adapt to stress.
At the tissue level, the initial formation of a blister is our body's immediate response to unfamiliar and excessive stress or friction, acting as a sort of cushion to protect deeper layers of skin. Overdo it, and the skin breaks down leaving a painful lesion. However, with repeated exposure to the same stressor, stopping just before we go too far, instead of forming blisters, our body develops calluses: areas where the tissue has thickened, hardened, and has become more resilient to the action in question.
The Body's Adaptive Mechanism
While the blister-to-callus transformation is a simple analogy, it serves as an excellent reflection of how our body's adaptive processes work on a larger scale. Our body is constantly evolving, adapting, and getting stronger in response to the stresses we place upon it.
We are not like motor vehicles that only break down over time; we are organic structures that change and grow in response to our environment. Just as our skin has its adaptive mechanism, every part of our body-- from muscles to bones, and even the brain-- has its own way of adapting to stress. Bones get denser with weight-bearing exercise. Our heart and lungs become more efficient with cardiovascular training. New neural pathways form that make challenging activities feel easier with repetition. Even avascular tissue such as cartilage, which many people believe only breaks down in time, can thicken and become more resilient in response to the right dose of activity.
Out of sedentary people, recreational runners, and competitive runners, who do you think would have the healthiest knees and hips? One well-known systematic review found that recreational runners most often had the least amount of hip and knee osteoarthritis (1). The sedentary people generally didn't do enough to stimulate growth and recovery, while the competitive runners often ran to the point of tissue breakdown. In weightlifters, flexing the spine under load excessively over time may lead to a disc herniation, but at the right dose, weightlifters may actually develop more resilient discs in their spines.
Adaptive Stress and Tissue Healing after Injury
When our body experiences stress, it activates a remarkable healing process. Adaptive stress, like physical activity, triggers our tissues to repair and reinforce themselves. This is a natural and proactive response: when an injured tissue experiences stress such as through tissue loading (i.e. gradually strengthening an injured tendon or muscle, beginning to slowly bear weight through a stable fracture, etc.) we trigger a small amount of ‘good’ inflammation. Cells rush to the injury site and chemical signals promote healing, and over time, tissues remodel, becoming stronger and more resilient. Healthy ‘good’ scar tissue forms. The body's ability to recognize, adapt, and respond to these stresses ensures not only recovery but, in the best cases, greater resilience against future injury. This intrinsic healing mechanism underscores the importance of balanced stress in making the best possible recovery from injury.
Adaptive Stress in Chronic Pain In cases of chronic pain, where discomfort persists sometimes even after tissues heal, the primary problem often lies in an over-sensitized nervous system. We might have overstressed our neural circuits to the extent that even minor triggers can cause disproportionate pain, or, following a particularly painful injury or flare-up, individuals might overcompensate and avoid potential stressors to such a degree that they gradually lose function, and their nervous system signals pain in response to activities and movements that used to come easy and feel pain-free. Graduated exposure-- slowly challenging this pain response over a long enough period of time-- helps to re-wire the nervous system back to a healthier state, decreasing pain and improving function.
Understanding the Bigger Picture
Although there are many people who I see in physiotherapy that need to slow down a little and take things easy, there are usually just as many who need to be coached to push things a little further into discomfort than they might be used to. Too often, we overestimate our limits and underestimate our body’s ability to adapt and thrive, and in the context of recovering from pain and injury, it's essential to understand and appreciate the power of adaptation our body holds. As with any adaptive process, consistency, patience, and understanding play a crucial role. This is where it is especially important to work with a trained professional who can help you identify your limits and point out where it is safe to challenge yourself. The next time you face a challenge, physical or otherwise, remember that with time, consistency and repetition, and a measured approach, your body is remarkably well-equipped to adapt, heal, and grow stronger. If you're curious to learn more about how the body responds and adapts to stress, or if you have specific concerns about a new injury or area of chronic pain, don't hesitate to reach out. Drop an email at firstname.lastname@example.org or book a session today. 1. Journal of Orthopaedic & Sports Physical Therapy Vol. 47, No. 6 Running and Osteoarthritis: Does Recreational or Competitive Running Increase the Risk?
Disclaimer: As always, the information provided here is for educational purposes only and is not intended as medical advice. Always consult with a healthcare professional before making any decisions regarding your health or injury. Individual conditions and needs vary and the recommendations in this article might not be suitable for everyone.