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.

Inclusion Criteria:

• Male professional football players.
• Actively playing for Anadolu Selçukspor in the Turkish Football Federation 2nd League.
• Training at a professional level.
• Having no reported health problems.
• Voluntary participation in the study.
• Providing written informed consent.

Exclusion Criteria:

• Having any health problem that could affect participation in the football match or study measurements.
• Having an injury or medical condition preventing participation in exercise.
• Refusal to participate or failure to provide written informed consent.
• Not completing the match protocol or pre- and post-competition measurements.

De-identified individual participant data that support the findings of this study will be made available from the corresponding author upon reasonable request.

Data will be available after publication and will remain available upon reasonable request.

Data will be shared with researchers who provide a methodologically sound proposal and use the data for academic and scientific purposes. Requests should be directed to the corresponding author.