NCSF Sport Nutrition Specialist Certification Practice Test – Complete Exam Prep

The correct answer is calcium, as it plays a different role in the body compared to sodium, potassium, and chloride when it comes to fluid balance. While calcium is essential for numerous physiological functions, such as muscle contraction and neurotransmission, it does not primarily function as an electrolyte for fluid balance within cells.

Sodium, potassium, and chloride are critical for maintaining osmotic pressure and fluid balance. Sodium helps regulate fluid volume and blood pressure, while potassium is vital for maintaining the resting membrane potential of cells and is involved in nerve impulse transmission and muscle contraction. Chloride also contributes to maintaining osmotic balance and is involved in the production of stomach acid, which is important for digestion.

Calcium's primary functions are more related to supporting bone health and facilitating muscle contraction rather than directly influencing fluid balance, which distinguishes it from the other three electrolytes mentioned.