Braking for Thirst Thirst signals the body's need for fluid. But some experts believe the thirst mechanism cannot be considered entirely reliable, and that slight dehydration has already occurred by the time a person becomes thirsty. For this reason, athletes and other active persons must be sure to consume adequate water for optimal performance. At one time, athletes were advised to take salt tablets to avoid salt depletion. However, experts now recommend consuming salty foods or sports drinks formulated to provide sodium as well as other nutrients.
Sodium naturally present in water also helps to replace that lost through perspiration.