What is the primary cause of muscle atrophy?

Muscle atrophy refers to the decrease in muscle mass and strength, and the primary cause of this condition is often associated with immobilization, inactivity, or loss of nerve stimulation. When muscles are not used regularly, whether due to a sedentary lifestyle, medical conditions, or certain injuries, they begin to shrink in size and strength.

In cases of immobilization, such as when a limb is in a cast or when a person is bedridden, the lack of movement means the muscle fibers do not experience the regular contraction and stimulation they need to maintain mass. Similarly, if there is a loss of neural stimulation, such as in nerve injuries, the muscles can become weak and atrophy over time since they aren’t receiving the signals necessary for contraction and growth.

While aging and wear and tear can contribute to changes in muscle mass over time, the immediate causes of atrophy are more closely linked to inactivity and the absence of stimulation. Excessive exercise without adequate recovery can lead to fatigue and temporarily impair muscle function, but typically does not result in atrophy when managed properly. Injury to muscles alone may cause localized swelling or damage but does not encompass the broader mechanisms that contribute to overall muscle atrophy seen with prolonged disuse or lack of stimulation.

Therefore