(This blog post is adapted from my book The Physiology of Yoga. Join our 8-week Physiology of Yoga book club which begins in January 2023.)
A principle that should be taught in every yoga teacher training is that our bodies have an inherent and profound ability to adapt. Unlike a car, which simply degrades over time, our bodies need the stress of exercise for optimum health!
Many tissues within the body—including muscle, bone, tendons, ligaments, fat, fibrous tissue, skin, lymph and blood vessels, fasciae, and synovial membranes—adapt to the demands placed upon them, meaning they can become stronger, more flexible, and more resilient. But they can also, if not loaded adequately, become weaker, less flexible, and less resilient.
Other tissues and systems can also adapt. The nervous system can adapt to learn new tasks or become better and more efficient at performing a task. It can even restructure its neurons to improve the way it delivers motor messages to muscles. The cardiovascular system can adapt to exercise to become more efficient at absorbing and transporting oxygen as well as removing carbon dioxide. Tissues can become more efficient at receiving oxygen. On a micro level, cells can become more efficient at producing energy from fat stores. Over the long term, all of these adaptations can improve health by reducing the risk factors for cancer, cardiovascular disease, type 2 diabetes, and many other diseases.
Without your realizing it, your body is constantly adapting to the everyday needs that your life dictates. If you had to walk up three flights of stairs to reach your apartment, your body would quickly adapt to that demand. If, however, you were on bed rest for a few weeks, perhaps because of an illness, you might then find your first climb up the stairs afterward more challenging. You might feel your legs fatigue more quickly; you might be out of breath more than usual. This is the effect of detraining—even if your only training is normal everyday activities.
Progressive overload describes a method of training whereby the stress placed upon the body is gradually increased to stimulate muscle growth and strength gain. Muscles get stronger, of course, which is known as hypertrophy, but connective tissue and bones also respond favorably. Knowing that reduced muscle mass, known as sarcopenia, is associated with aging and lack of physical activity, we can all benefit from keeping strong and active even into old age.
An obvious example of adaptation with progressive overload is weightlifting, where a gradual increase in volume (number of repetitions) and intensity (percentage of maximum capacity) are the defining aspects. But does the same apply to yoga?
A load is a load, and yoga provides many opportunities to load the body in a variety of ways. You have probably experienced the effect of adaptation in the body. You might recall struggling with a certain yoga pose, then that pose becoming more comfortable as you practiced it. Or perhaps you felt your first strong yoga class was difficult to keep up with, but, over time, a similar level of class became doable.
Though the practice of yoga does not tend to incorporate any resistance beyond the practitioner’s own body weight, yoga still offers an adequate stimulus for adaptation. Newcomers to yoga are often surprised at how challenging the practice can be and that yoga can even elicit delayed-onset muscle soreness, a sign of strength-building stimulus. Because a yoga practice is ever changing (unless a strict sequence is religiously followed), there are always new ways to effect change in the body.
If adaptations were to plateau, however, there are still many ways to progress a yoga practice. One could, of course, increase the frequency of one’s practice (remembering though that adequate rest is important in the adaptation process). One could increase the intensity of the practice by simply holding poses longer, using repetition of poses, following a stronger style, or focusing on poses that engage many muscle groups, such as standing poses like Warrior II (Virabhadrasana II). Though yoga provides a variety of ways to build strength, flexibility, and resiliency, yoga practitioners still might benefit from adding strength training sessions outside of their yoga practice, where they lift loads beyond their own body weight by using dumbbells, barbells, or resistance bands.
We retain this ability to adapt throughout life. The idea that exercise (including yoga) might damage tissues through "wear and tear" can be harmful because it can discourage people from moving and loading their tissues, some of the most beneficial things we can do for our body. Rather than talking about wear and tear, consider movement and loading as wear and repair. While frequency and intensity of exercise do matter and ongoing health conditions must be considered, remember that as long as you are alive, you can retain the power to adapt, become stronger, and become more resilient.
Want to learn more cool physiology facts to make you a better yoga teacher? Join our 8-week Physiology of Yoga book club which begins in January 2023.