What condition involves the breakdown of muscle tissue, often due to excessive exertion?

The condition that involves the breakdown of muscle tissue, often as a result of excessive exertion, is Rhabdomyolysis. This serious condition occurs when muscle fibers break down and release their contents, including myoglobin, into the bloodstream. High levels of myoglobin can lead to kidney damage and other complications. Rhabdomyolysis commonly occurs in situations involving strenuous exercise, especially if the body is subjected to excessive heat or dehydration.

In contrast, Hyponatremia refers to a low sodium level in the blood, usually caused by excessive water intake or loss of sodium. Heat exhaustion is a heat-related illness characterized by heavy sweating and a rapid pulse, resulting from prolonged exposure to heat, but does not involve muscle tissue breakdown. Heat stroke is a more severe heat illness with high body temperature and altered mental state, which can occur from prolonged exposure to high temperatures, but like heat exhaustion, it does not directly involve muscle tissue damage. Thus, Rhabdomyolysis is clearly the condition associated with the breakdown of muscle tissue due to excessive exertion.