What is a primary cause of Exertional Hyponatremia?

• A. Dehydration
• B. Hyperhydration
• C. Vigorous sweating
• D. Heat exposure

Answer: (B)

Exertional Hyponatremia is a condition characterized by low sodium levels in the blood, typically associated with prolonged physical activity, particularly in endurance sports. The primary cause of this condition is hyperhydration, which occurs when an individual consumes excessive amounts of fluids, often in an attempt to prevent dehydration during exercise.

When a person drinks large quantities of water without adequate sodium intake, it dilutes the sodium concentration in the bloodstream. This dilution can lead to an imbalance in electrolytes, causing the symptoms of hyponatremia. In endurance events, especially, athletes may underappreciate their sodium needs while focusing on hydration, leading to an improper balance of fluids and electrolytes. Proper hydration strategies should include not just water, but also electrolytes to maintain sodium levels.

The other factors mentioned can contribute to overall hydration strategies during exercise but do not directly cause Exertional Hyponatremia as hyperhydration does.