Which of the following electrolytes is primarily lost through sweat?

Sodium is the primary electrolyte lost through sweat during physical activities. When the body heats up and begins to sweat, sodium, along with other electrolytes, is excreted to help regulate body temperature and maintain fluid balance. Sweat primarily consists of a significant quantity of sodium, which is crucial for various bodily functions, including nerve transmission, muscle contraction, and fluid balance.

While potassium, calcium, and magnesium are also important electrolytes, they are not lost in as high concentrations as sodium during sweating. Potassium can be lost through sweat, but sodium accounts for a greater proportion of the total electrolyte loss during exercise. Understanding the role of sodium in hydration and muscle function emphasizes its importance in the context of athletic performance and recovery. This is why sodium is typically emphasized in discussions regarding electrolyte replenishment for athletes and individuals who engage in prolonged physical exertion.