Fluid replacement in sports

Peer-reviewed / reviewed during preparation

Position of the working group sports nutrition of the German Nutrition Society (DGE)

Introduction

Adequate hydration is an important precondition for the health and performance of athletes. The quantity and type of fluid intake before, during, and after exercise affect an athlete’s performance. Both inadequate and excessive fluid intake has a negative effect or represents a health risk. In the past athletes have frequently been guided by the principle “drink before the thirst hits”. However, this can increase the risk of hyponatremia (“water intoxication”), which in extreme cases has already led to deaths of recreational athletes (triathletes and marathon runners) [1–3]. This highlights the particular importance of fluid intake in sports.

Since water and electrolyte levels are closely connected, the composition of drinks also plays a role in water absorption. In the following article the importance of balanced fluid and electrolyte levels for sporting performance as well as the benefits and risks of fluid intake in sports are presented. From statements by international specialist associations, recommendations are derived for fluid intake for all kinds of sporting activity.

Abstract

Recommendations for drinking quantities during all kinds of exercise provide some guidance for athletes on how to avoid health problems and performance impairment. Sporting activities should always be commenced with a balanced fluid level (apparent by urine colour, which is light yellow in the case of balanced fluid level). The weighing method to determine individual fluid loss offers guidance as to optimal fluid intake during exercise. In principle however, athletes should trust their own feeling of thirst. Generally in the case of activities lasting less than 30–40 minutes, fluid intake is not necessary, minor fluid deficits during exercise are tolerable. In the case of longer-lasting activity (> 1.5 hours) it is advisable to take in beverages rich in carbohydrates and sodium. After sport, fluids and electrolytes must be replaced.

Keywords: sports nutrition, fluid intake, fluid and electrolyte balance

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