To keep our body healthy, we need to do what it feels the most comfortable. And yes, you guess it right, our body feels the most comfortable when we move it regularly.
Almost all our body parts are designed to move, even our internal organs – our heart beats, our lungs expand, our gut moves, our blood flows, etc.. Imagine if they are not moving regularly. Our heart weakens, and stamina drops. The air in our lungs goes stale, and we contract pneumonia more easily. We get constipation. We get blood clots in our legs/heart/brain, which can be life-threatening.
For our musculoskeletal system (muscles, bones, joints and the related nervous system), “exercise is medicine” is especially true because the primary function of these body parts is movement.
Exercise is medicine for joints
When you gently touch your elbow or knee joint, you will feel a gap between the bones. What is there in the gaps?
Soft tissues in these gaps are secreting a fluid called synovial fluid. This synovial fluid acts as a lubricant to keep our joint movement smooth, much like how we spray WX-40 to a door hinge when it gets rusty. The more we move our joints in a moderate manner, the more this fluid is secreted by our body – and vice versa. If you or you know someone whose joint has to be immobilised due to injury or fracture, you will know how stiff the joint can get within days (both the patient and the therapist have a hard time getting rid of this stiffness!). If you “voluntarily” immobilise yourself, i.e. always staying in one position for prolonged periods, the body will react in the same way, just that it takes slightly longer time.
Exercise is medicine for muscles and tendons
Our muscles grow when we do strengthening exercises, we all know that. But what’s wrong with not strengthening our muscles if our work and lifestyle are desk-bound or couch-bound anyway?
You are half right. If you are not a professional athlete, you may not need super strong muscles. But even if you don’t intend to play any sports, at the very least you want to maintain a good sitting posture to prevent the many spinal problems (see “What is the Good Posture for the Spine”). And for that you still need strong-enough muscles to hold your body weight up against gravity. Do not take your current muscle strength for granted. If you don’t keep it, you lose it. Many elderly retired to walking frames or wheelchairs and are prone to fall because they lose much muscle mass over time. Research shows that it is never too old to do strengthening exercises, not even to mention when we are young.
Tendon is the soft tissue that connects muscle to bone. It also gets stronger (firmer) when we load them moderately. Tendinopathy, a condition that always affects the tendons at the shoulder/knee/ankle, results not only from overloading but also underloading of the tendon. A certain chemical composition, stimulated and maintained by moderate loading, is required for a healthy tendon. The moment we offload the tendon for prolonged periods, the chemical composition is disrupted, and the tendon gradually softens like jelly.
Exercise is medicine for bones
Do you realise there are a lot of bony prominences in our body, for instance at the wrist/knee/ankle etc.? Our bones grow according to how we load them. The more traction applied, the more prominent they grow. The more weight applied, the denser it becomes. The latter is one of the significant ways to prevent osteoporosis. When you sit all the time, your legs will always be offloaded. Then the leg bones are in a higher risk of being brittle and fractured.
Exercise is medicine for proprioception
The word “proprioception” sounds complicated. But it isn’t that complicated when I quote this daily example: do you have a friend who often trips over a curb for no reason, stating that s/he doesn’t know why s/he cannot lift the leg high enough to clear the step?
Proprioception is the joint sense, and it comprises many different types. In general, imagine your bones/muscles/tendons/joints are the hardware for your movements, and proprioception is the software. This software helps you fine-tune your movements so that you can adjust your body parts to the environment or your need. For example, to reach a particular angle for an elegant dance move without looking at it, or maintaining balance when walking/running on uneven ground, or simply to avoid tripping over a curb while walking and looking around at the same time.
Don’t think merely sitting down does not require good joint sense. For so many times, I took photos to show my patients that their sitting/standing postures were out (either too straight or too slough) when they think they are in the right posture. Their proprioception was out, and their joints mistook a stressed posture as a neutral posture. Sharpen your joint sense through exercises. This will help you prevent some injuries, or even enable you to perform some elegant sports moves.
Exercise is medicine for all
If you are already doing exercises regularly, share this article with your friends who still hesitate to do so. If you have not been exercising regularly, this article is dedicated to you. This article details how exercises benefit our musculoskeletal system, but the benefits of exercises are far more than what is described here. Don’t go for extreme speed/range unless you are an elite athlete, start/keep moving regularly and avoid staying still for prolonged periods, and your body will thank you for that.