Fluid Replacement for the Physically Active: Position Statement by NATA

To present evidence-based recommendations for optimized fluid-maintenance practices for physically active individuals.

Hydration Levels:
- Hypohydration: Lack of adequate fluid intake compromising athletic performance.
- Hyperhydration: Excessive fluid intake that also poses health risks.
- Both conditions can impact athletic performance and increase health risks.
Athletes must prevent hypohydration while being cautious of risks like overdrinking and hyponatremia.
Drinking behavior can be influenced by education, accessibility, experience, and fluid palatability.
Updates recommendations on fluid replacement strategies for physically active individuals.

Education on Fluid Replacement:
- Physically active individuals should be educated about benefits of hydration for performance and the risks of both hypohydration and hyperhydration.
Quantifying Sweat Rates:
- Individual sweat rates should be assessed during exercise across different environments.
Fluid-Replacement Practices:
- Encourage practices promoting sufficient, balanced hydration throughout activity.

Hydration Status: Total body water maintained within 1% hyperhydration to 3% hypohydration.
Euhydration: Optimal total body water content regulated by the brain; functions well-facilitated.
Hyperhydration: Excess fluid leading to swollen cellular volumes.
Exercise-Associated Hyponatremia (EAH): Serum sodium concentration below 135 mmol/L occurring within 24 hours of exercise.
Dehydration: Process of losing body water, typically through sweating or other avenues (e.g., urine, respiration).
Hypohydration: Deficit of body water leading to effects on performance and health.

Many athletes (over 50%) arrive at athletic events in a state of hypohydration.
When fluids are available as needed, individuals replace approximately two-thirds of sweat losses during activity.
Optimal hydration supports thermoregulation and cardiovascular function.

Extreme Hypohydration leads to health risks and impaired organ function. Severe hydration issues, including EAH, pose significant dangers, including brain edema and respiratory failure.

Euhydration: Optimal total body water.
Hyperhydration: Excess fluid volume.
Exercise-Associated Hyponatremia (EAH): Sodium deficiency during/after exercise (<135 mmol/L).
Dehydration: Water loss through various means.
Hypohydration: Water deficit continuum impacting performance and health.
Ad Libitum Drinking: Drinking per individual preference without thirst assessment.
Drinking to Thirst: Consuming fluids based on thirst signals.