Why electrolyte balance matters for performance and health
Electrolytes regulate fluid balance, nerve impulse transmission, and muscle contraction. Significant electrolyte losses through sweat—particularly sodium—can impair exercise performance, cognitive function, and in extreme cases contribute to hyponatraemia (low blood sodium) when replaced with plain water alone.
Sodium is lost at rates of 500–1,500 mg per hour of exercise depending on sweat rate, making it the electrolyte most likely to require replacement during prolonged activity. Potassium losses are more modest (~100–200 mg/hour) and are usually replaced through diet. Magnesium losses are relatively small through sweat but chronically low dietary intake is common.