The Importance of Hydration for Endurance Athletes

April 20, 2016

Some athletes drink too much, others are not drinking enough. How much are we really supposed to consume to achieve optimal performance?

Why is hydration important for athletes?

Water makes up 70% of your body and when you exercise your temperature rises, you sweat, and essentially lose that water weight. It is important to replace what is lost, otherwise your mental functions, decision-making, concentration, and skills are prone to suffer. This is the last thing you want to happen on race day!

The amount you need to hydrate your body will always depend on your gastric emptying rate (the time it takes for your stomach to empty the water), your tolerance, and your opportunities to drink during your session/race.

Having a basic understanding of hydration will help you determine a drinking plan in order to remain hydrated at all times before, during, and after your race! Treat your body like a temple!

What should I drink and when?

Before any exercise, you should drink 3-5 mL of water/kg of bodyweight. In other words, this is approximately 1 cup of water for a 60 kg athlete. Based on this you can calculate your personal needs!

During your exercise session, you should drink between 12-24 oz. every hour. That is around 300-700 mL per hour. Electrolytes and carbohydrates are necessities to add to your drink if the training last more than 60 minutes. To give you an idea, 600-800 mg of sodium should be consumed per hour for workouts lasting more than 60 minutes. Check the label of your drink to see if it has enough for your specific needs! Carbohydrates can be taken as a solid or via fluid/gel/powder.

Hydrating after exercise is so important, and many people forget to do so! Make sure to replace all of the lost fluids by drinking at least 1-1.5 L of water within an hour of exercise!

Should I be concerned about dehydration?

Dehydration is a serious condition and can lead to death if untreated and ignored. Dehydration will not only impair your performance and endurance but will change the composition of your blood, making it thicker. Therefore, the blood circulation will be impaired, the heart rate will increase and less oxygen will be carried to the muscles. Fatigue, cramping and headaches will follow as common symptoms. Major dehydration is characterised by a 2-3% loss of body mass, which is quite small in number but can have devastating consequences and long-term effects on your body!

Some tips to help you understand hydration levels:
  • Urine is the best indicator of hydration. It should be a pale yellow colour like lemonade and should be in good amounts. If urine is dark in little amount, adjust your hydration.
  • You can also weigh yourself before and after a session. The loss of 1 kg usually means that 1 litre of water was lost. So drink up!
  • Thirst is also a good indicator for some, but often delayed or absent in others. So do not always rely on it and try to sip every 10-15 minutes even if you are not thirsty! You might not be thirsty but your body will be!

What about Overhydrating?

Water intoxication can happen to anyone guzzling down water due to a fear of becoming dehydrated. Water intoxication is when you drink too much water and it doesn’t contain any electrolytes, particularly sodium. Hyponatremia will occur because the excess water in your blood dilutes the amount of sodium in your system!  

It often happens during Ironman and marathons to athletes that want to stay hydrated but forget to consume enough electrolytes. Very hot conditions and fatigue are also factors affecting this condition. Finding a balance between dehydration and overhydrating is important for athletes of all sports!

Make sure to power up your water with some electrolytes!

Hydration tips!

Remember to hydrate your body everyday, even if you are not exercising. An athlete's body must not only be respected while training, it has to be maintained on a daily basis. Try to pay attention to any thirst indicators during your training and urine colour!  

Tips to stay hydrated:
  • Cold drinks help to increase performance and diminish body temperature.
  • Everyone loves flavoured drinks, so try it out! Might help you increase liquid intake.
  • Always have a bottle with you during your workout so that you do not forget or find excuses not to drink!


Marina Parent

Dietitian-nutritionist, dtp.



Photo Credit: Freepik

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