Which of the following pairs of electrolytes are commonly lost in sweat?

Sodium and chloride are the primary electrolytes lost in sweat. When the body heats up during exercise or in hot environments, it regulates temperature through perspiration. Sweat primarily consists of water, but it also contains various electrolytes, with sodium and chloride being the most abundant. These electrolytes are essential for maintaining fluid balance, nerve function, and muscle contractions.

Sodium plays a crucial role in retaining fluid and is vital for hydration. Chloride, often found in combination with sodium as table salt (sodium chloride), helps maintain osmotic balance and is important for digestive health. When athletes sweat, they lose significant amounts of these electrolytes, which can lead to imbalances if not replenished.

Other options mention electrolytes that are important for various bodily functions, but they are not the predominant electrolytes lost through sweat during physical activity. Potassium is also lost in smaller amounts, but sodium and chloride are the key players in sweat composition. Calcium, phosphate, bicarbonate, and sulfate serve different functions in the body and do not play as significant a role in sweat electrolyte loss. Thus, the focus on sodium and chloride highlights their critical function in hydration and maintaining electrolyte balance during exercise.