How does it happen that when we work out, our muscles grow, and when we stop, they “disappear”? According to a common theory, when we train, we change fat into muscles, but when we stop – muscles change into fat. Is it possible? What happens with our muscles and why are regular workouts so important?
Do muscles transfer into fat after leaving off training?
It's physiologicallly impossible. Neither fat is able to change into muscles, nor muscles into fat. However, the fact is, that when we train with load, we build muscle tissue, it usually happens that we decrease the content of body fat, but not necessarily. The truth is that if very active people resign from physical activity, they may gain weight and worsen their body composition. In other words, they may lose muscles and gain fatty tissue. It usually happens because of unadjustedness of diet to the new demand for energy. Moreover, lack of stimulation for muscles, which happens during training with load, leads to decrease of muscle tissue after some time. It is connected with the body's adaptation to the circumstances.
The pace of losing muscle tissue is partly conditioned by somatotype. For a typical ectomorph, the loss of muscle tissue will be quite fast. For some ectomorphs it's the matter of few days without strength training together with undernourishment to notice visible losses of muscle mass.
For endo- and mesomorphs the losses of muscle mass will not occur so fast. However, for them, especially for endomorphs, unadjustedness of calories supply to the current physical activity may contribute to the increase of fatty tissue.
How do muscles grow?
Muscle hypertrophy, which is building muscle mass, is the basic aim of resistant training. Muscles are built of muscle fibres. Building muscles undergoes thanks to micro injuries of muscle fibres, which take place during training. However, to be able to notice the increase of muscle mass, the injured fibres have to recover. That's why proper nutrition and rest are so important. Workout itself provides us only with micro injuries of muscle fibres, whereas, the process of building it happens during rest, under the condition that specific conditions are met.
Muscles become bigger and stronger, because the fibres rebuild after micro injuries, they also get stronger and adjust to current conditions. That's why strength progress is so important in training, as well as intensification and variety of exercises. Body gets used to physical effort after some time, so if we care about rebuilding muscle fibres,we have to remember about regularity of workouts and their intensification. At the same time, we should take care of proper nutrition and recovery.
To sum up, building muscle tissue depends on the regularity of training and its intensity, as well as proper nutrition and proper amount of sleep. As a result of stopping training, we may observe the decrease of muscle mass. But it doesn't happen from day to day. The speed of observing the loss of muscles depends on a few factors, among others, on the somatotype of our bodies.