GLOSSARY

Electrolyte Replenishment replaces relevant electrolytes lost around activity, guided by losses, intake and the athlete's circumstances.

Post-exercise rehydration replaces a fluid deficit while accounting for continued losses. Body-mass change measured under comparable conditions provides a practical estimate, but wet clothing, food intake, urine and fuel changes complicate interpretation. Sodium in food or drink helps retain ingested fluid. When rapid replacement is needed, the amount drunk may exceed the measured deficit to compensate for urine losses; this is not an instruction to force unlimited water. Spread intake and assess the actual situation.

Drinking volume and retained volume are different quantities. Rehydration efficiency describes how much of an intake remains in the body over a defined observation period, while net fluid balance also includes losses and the starting deficit. A drink can show high retention without fully correcting the original deficit. Sodium, beverage composition, accompanying food and measurement timing affect interpretation. Restored body mass alone does not prove that every fluid compartment or electrolyte disturbance has normalized.

Fluid planning should consider sweat losses, conditions, tolerance and opportunities to drink. Carbohydrate and fluid needs can differ, so a single beverage may not meet both without adjustment. Excessive drinking can also be harmful; more fluid is not always better. Sodium provision may be relevant in selected prolonged or high-loss situations, but it does not make unlimited drinking safe. Practice the combined food-and-fluid plan in training and evaluate actual intake and symptoms rather than relying only on a product label.