Hydration in sport is vital to replace the loss of fluid that our body perspires, which controls our body temperature as we utilize energy.

If we do not replace this fluid we overheat and dehydrate, which may lead to a decrease in performance and an increased risk of injury.

To minimize dehydration, athletes need to drink enough in exercise to match their sweat loss.

To determine sweat loss, the best way is to weigh an athlete before and after exercise. Each kg of weight loss equals 1L fluid loss. To calculate the fluid loss for the exercise session, the athlete must also factor in the amount of fluid consumed during the exercise session. For example, if an athlete finishes 1kg lighter and has consumed 1L of fluid during the session then total sweat loss is 2L. This calculation will help to guide the athlete on how to maintain hydration in their exercise session.

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Key points in hydration are:

  • If exercising for less than 45-60 mins, then water is sufficient hydration;
  • If exercising greater than 45-60 mins, then we need to consider sports drinks. These are generally flavoured to encourage greater fluid intake;
  • Sports drinks should contain 6-8% carbohydrate, as well as electrolytes such as sodium and potassium. This will promote fluid absorption, replace the electrolytes lost in perspiration and provide a fuel source.

Dehydration impairs performance by causing:

  • increased heart rate;
  • increased perceived exertion;
  • impaired heat regulation;
  • reduced mental function;
  • reduced skill level;
  • stomach upset.