When we look at our ancestors, our species "homo sapiens" has always been in motion. Exercise was necessary for survival because food had to be sought, danger avoided, hunting was needed, and protection from the climatic challenges; however, if we now look at our society, exercise has become a "burden" for many. Very often we "sit" for hours behind our computer, drive cars, have groceries delivered at home and our refrigerator is usually very close by. We do not really need exercise anymore to survive. However, we need this exercise for a good and healthy homeostasis in our body. In short: not moving is equal to stress and therefore equal to "inflammation"!
Sedentary lifestyle is one of the biggest stressors of our time. Chronic low-grade inflammation and insulin resistance are the result and cause symptoms related to disposal of muscles (muscle wasting), the cardiovascular system (high blood pressure, atherosclerosis), the gut (digestive problems and nutritional intolerances) and even of our brain (concentration and memory disorders) because these organs receive less energy. The body is, as it were, at the service of the immune system, which runs with most of the available energy. As far as muscle breakdown is concerned, this happens in a sort of order from importance to "survival".
The first muscle to lose its contraction force is the diaphragm. As a result, the lower lung lobes are no longer well ventilated, making the person more susceptible to lung diseases. If the diaphragm already has muscle loss This gives a typical stabbing pain in the silk when exercising. The second muscle is the heart! Insulin resistance breaks down the fast Type 2 muscle fibers (which depend on glucose) and increases the slow Type 1 muscle fibers (which can burn fats via Beta-oxidation. The heart becomes slower and less flexible, making one more susceptible to cardiovascular disease. The following muscles are the muscles of the lower body and then those of the upper body, the arms more specifically. This is logical in the context of our "primal" history: in the event of danger, the last resort is to climb up a tree, for example, after we cannot run any further because we are exhausted, or our enemy is overtaking us. If the arms have also become weak, survival is very limited. The latter is called "frailty syndrome" and can be measured, for example, by having the person squeeze your hands. If it is very weak, life expectancy is very short.
This order is important in order to do correct muscle training in people who have been sedentary for a long time. For example, if you first start training the diaphragm or the heart, you will stimulate the immune system by releasing IL-6 (interleukin 6), among other things, and you will get a flair-up of the disease. For example, in people with atherosclerosis, it is very important to first train the arms, then the lower body, before you start cardio-training, in order to avoid a vascular inflammation that can provoke an infarction. First of all, insulin resistance must be improved or better disappear by training peripheral muscles, with or without nutritional changes, in order to obtain more oxygen, more mitochondrial function and better blood circulation in the heart.
The message is therefore: first train the muscles that are most recently neglected in sedentary life and are therefore the most stable metabolic, and then build up progressively. So, if you are completely out of shape, first train the arms, then the legs, then endurance (the heart) and finally the diaphragm muscles.