The Importance of Hydration During Exercise


Water is a vital part of our daily lives; however, it becomes even more crucial before, during and after exercise. Water assists in regulating our body temperature, supports muscle movements and maintains blood volume. Our bodies require adequate fluid intake to perform these functions.

It is crucial to replenish fluid loss from sweating due to physical exertion. The amount of water required is relative to the level of exercise we are undertaking.

It is important to understand the intensity of the exercise we are undertaking to be able to comprehend how much we will need to hydrate in order to replenish water loss.

Dehydration is common when participating in prolonged and intense exercise in the heat. If the water loss is not replenished correctly it can lead to the following side effects:

  • Chills
  • Clammy skin
  • Elevated heart rate
  • Nausea
  • Headaches
  • Dizziness
  • Shortness of breath
  • Dry mouth

Dehydration can further lead to more serious side effects:

  • Heat exhaustion
  • Heat stroke
  • Muscle cramping/fatigue
  • Breakdown of skeletal muscle

Hydrating during physical activity is crucial for your body to be able to perform well. If required hydration levels are not met, performance can decrease significantly. It is also important to understand that the more you sweat or exert yourself during exercise, the greater your loss of fluids. A loss that is greater than two percent can lead to more serious effects such as nausea, vomiting and gastro-intestinal problems.

It is also possible to over-hydrate; due to consuming too much liquid at one time. Although very rare, over-hydration can lead to hyponatremia which can result in death in severe cases.

Tips for staying well hydrated during exercise

  • Always start exercise well hydrated; this will lower the risk of becoming dehydrated
  • Develop a plan for drinking during exercise based on your own sweat rates
  • Weigh yourself Immediately before and after exercise to monitor your weight change to estimate your final fluid deficit (1 Kg is equivalent to 1 Litre of fluid)
  • During recovery, you will continue to lose fluids through sweating and urine losses, so plan to replace 125% -150% of this fluid deficit over the next 2-6 hours.
  • Drink fluids with your recovery snacks and the post-exercise meal to achieve this goal
  • Be prepared! Make sure that you take a large water bottle with you, or have access to water, whenever you exercise.

Water vs Sports drinks

Water is easily accessible and has a number of health benefits including that it contains no kilojoules. It is often the best fluid replacement for low-intensity and short duration exercise. There are alternatives you can consider for high-intensity or endurance training.

Sports drinks can act as another option for hydration for additional replenishment as they contain the required carbohydrates and electrolytes that will restore energy sources. Sports drinks can be used when completing high-intensity workouts or prolonged endurance sessions. Sports drinks do however contain high levels of sugar and should be consumed in moderation rather than in large amounts.

Natural fruits and vegetables are another alternative that should be consumed after exercise as they can contain high levels of water. Some examples are:

  • Oranges
  • Watermelon
  • Cantaloupe
  • Pineapple
  • Cucumber
  • Zucchini
  • Tomatoes
  • Lettuce

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