Which two electrolytes are most commonly supplemented by athletes to replace those lost in sweat?

• A. Calcium (Ca^{2+}) and magnesium (Mg^{2+})
• B. Bicarbonate (HCO_3^-) and sulfate (SO_4^{2-})
• C. Sodium (Na^+) and potassium (K^+)
• D. Chloride (Cl^-) and phosphate (PO_4^{3-})

Answer: (C)

Verified step by step guidance

1. Understand that electrolytes are ions that conduct electricity in the body and are lost through sweat during physical activity.
2. Recognize that the most important electrolytes lost in sweat are those involved in maintaining fluid balance and muscle function.
3. Identify sodium (Na^{+}) as a primary electrolyte lost in sweat, crucial for fluid retention and nerve function.
4. Identify potassium (K^{+}) as another key electrolyte lost in sweat, important for muscle contraction and cellular function.
5. Conclude that sodium (Na^{+}) and potassium (K^{+}) are the two electrolytes most commonly supplemented by athletes to replace those lost in sweat.