electrolyte drink

A drink that contains mineral salts, such as sodium. It is taken during or after exercise to replace mineral salts lost by sweating and to avoid heat cramps.

There are three main types of electrolyte drink:

• HYPOTONIC DRINKS are watery and have a lower mineral salt concentration than body fluids; they provide the fastest possible rehydration. The mineral content of these drinks is present simply to ensure rapid uptake of fluid across the small intestine
• ISOTONIC DRINKS have a mineral salt concentration the same as normal body fluids; they are designed to rehydrate and deliver energy to working muscles
• HYPERTONIC DRINKS have a mineral salt concentration greater than that of body fluids; they have a high carbohydrate content and are designed to boost energy during endurance activities.

Fluid uptake from the small intestine is greater if the drink has a lower salt concentration than body fluids. Hypotonic electrolyte drinks, therefore, are the most effective at preventing dehydration. During exercise, the salt content of sweat decreases while the salt concentration of the body fluids increases. Therefore, replacing salts without also replacing enough water will increase the state of dehydration and may adversely affect performance. Any individual can restore their electrolytes (salts) by eating a well-balanced diet. There are no conditions encountered by normal athletes or recreationally active individuals when salt tablets are required. See also water replacement.

A drink containing electrolytes, such as sodium and potassium salts, usually taken to replace mineral salts lost during sweating and to avoid heat cramps. Sodium salts are the most important electrolytes in these salt-replacement drinks. As exercise progresses, the salt content of sweat tends to decrease, proportionately more water is lost, increasing the salt concentration in the body. Therefore, electrolyte replacement without adequate water replenishment will increase dehydration and may adversely affect performance. See also energy drink.