Background: In sports requiring intense physical exertion, particularly in endurance-based disciplines such as football, exercise-induced fluid and electrolyte losses can have adverse effects on thermoregulation, cardiovascular stability, and neuromuscular functions. Failure to balance these losses with adequate and timely rehydration increases the risk of performance decrement and injury. Although the literature indicates that intermittent and individualized fluid intake can mitigate these physiological effects, experimental studies conducted under field conditions with professional athletes remain limited. In this context, the purpose of this study is to evaluate the effects of intermittent water consumption administered during competition on exercise-induced changes in body weight and basic serum electrolyte levels (Na⁺, K⁺, Ca²⁺, Cl-) in professional football players.
Methods: Twenty-two male football players participated in the study and were randomly assigned to either the experimental (intermittent water intake, n=11) or control (ad libitum water intake, n=11) group. Both groups played a 90-minute match; body weight and serum electrolyte levels were measured before and after the competition. The experimental group was provided with a total of 10 mL/kg of plain water, administered before the match and at half-time.