Quick guide to electrolytes

[Sports Science Editor]

Electrolytes are chemical substances that become ions (positively or negatively charged) in solution and acquire the ability to conduct electricity. They are present in the human body and the right balance is essential for cells and organs to function properly.

Common electrolytes include sodium, potassium, chloride and bicarbonate. Too much or too little of an electrolyte can cause cells to malfunction and extremes in blood sodium levels can be fatal.

During exercise, you lose electrolytes in your sweat, particularly sodium and potassium. These must be replaced which is why so many sports drinks contain sodium chloride and potassium chloride.

Research has demonstrated that effective electrolyte replacement during prolonged exercise is an important factor determining an athletes ability to perform to their full potential. In tests comparing the impact of consuming pure versus a carbohydrate-electrolyte drink, results show that those athletes consuming a carbohydrate-electrolyte drink will experience improved performance, particularly in the latter stages of exercise.

Most athletes are aware of the need to avoid dehydration, but beware of excessive fluid intake, a big risk factor for developing hyponatraemia (low sodium levels). How you pre-hydrate and your drinking strategies during exercise can affect your fluid balance. Checking your weight before and after longer training sessions can indicate how well you are keeping up with or possible exceeding your sweat losses. A weight loss of 1-2kg is an indication that your fluid intake needs to increase. If you gain weight during training, your drinking may be excessive.