How to stay hydrated for training and racing

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Did you know that 50-60% of the human body consists of water? Drinking enough water is vital for our physical and mental health. It’s important for the blood, brain, digestion, heart, muscles, lungs… in short, the entire body! When we train, we sweat – which is why it’s important to drink more in order to stay hydrated. Your recommended fluid intake will depend on the intensity and duration of your workout, as well as the climate. The amount of water you should drink also depends on your body composition, along with other factors such as sex, body fat percentage and age. Below you’ll find all the information needed about staying well-hydrated when running!

1. How much fluid should be consumed in a day?

Muscles contain more water than fat does, and it’s natural for women to have a higher body fat percentage in comparison to men. As a result, men generally require a higher daily volume of water than women. The recommended water intake for women over the age of 19 is around 74 fl. oz / 2.2 liters /9 cups per day. It’s recommended that men of the same age drink 101 fl. oz / 3 liters / 13 cups per day. (1) These numbers don’t take any workout or weather conditions into account – so when running and sweating a lot, your recommended water intake will increase accordingly.

2. How much fluid is lost during exercise?

The harder and longer you exercise, the more fluid you’ll need to drink before, during and after your workout. However, it can be difficult to measure optimum fluid levels as individuals are all different, in terms of how much they sweat during the workout. 

An easy way to find out if you’re consuming enough fluid is by checking the colour of your urine in the morning. If the colour is dark, it is probably due to your fluid intake being too low. (2)

2. Is it dangerous to drink too little?

It’s normally not essential to drink anything during a run lasting one hour or less, although this will depend on factors such as climate. The longer you work out, the more fluids you will lose from sweat, and the more the body will be affected by dehydration. If your run lasts for longer than an hour, you will most likely benefit from replacing lost fluids. The more fluid you lose without replacing it, the poorer your performance will be. (3)

When you sweat, you lose fluid along with electrolytes – especially sodium. Fluid balance refers to the correlation between fluids and electrolytes in the body, with sodium playing a major role. When you drink water alone and sweat heavily without replenishing this lost sodium, there will be an imbalance which can have a negative impact on the heart and other organs. (4) Sports drinks usually contain water, a small amount of carbohydrates and some electrolytes such as sodium. These are beneficial for runs lasting longer than an hour, helping maintain your body’s fluid balance and achieving the best possible performance. (3) It’s easy (and cheap) to make a homemade sports drink. Simply blend water with a little salt and something sweet such as juice. (5) 

3. Drink more in a warm climate

The climate’s humidity and temperature will also affect how much water your body requires. In conditions with low humidity you lose more fluid through breathing alone – and in a warm climate, it’s normal to sweat more, which means you need to drink more. (2) When body temperature increases significantly, sweating prevents overheating. (3) This is why it’s paramount to drink large amounts of fluids when running in a warm climate or running long distances. Keep in mind that it can take around 2-3 weeks before the body adapts to new climate conditions. (6)

4. Drink little at a time

To avoid dehydration when you’re running or working out for more than one hour, it’s a good idea to drink small amounts of water throughout the day (7). This is more beneficial than taking in large amounts of fluid halfway through the workout, when you may have already reached the state of dehydration. Additionally, drinking large amounts at once might cause gastrointestinal distress. (5) To avoid this altogether, start sipping small amounts of water throughout your day, as well as during your workout to stay hydrated.

5. Track your water intake

A great way to ensure you are drinking enough water is by using a tracking tool. Be sure to track your water intake along with your workouts to reach your daily water requirements!

References

 1. Institute of Medicine. 2005. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. Washington, DC: The National Academies Press. https://doi.org/10.17226/10925

 2. Sveriges Olympiska Kommitté (SOK). Kostrekommendationer för olympiska idrottare. 2016. https://sok.se/download/18.3e3b95e91555e5c9d8b6a15e/1466669159954/Kostrekommendationer+för+Olympiska+Idrottare_Version+hemsidan_juni2016.pdf

3. Andersson, A. Idrottsnutrition. I Näringslära för högskolan, Abrahamsson, L., Andersson, A., Nilsson, G (red.),160-179. Stockholm: Liber AB, 2013.

4. Branth, S. Vatten, vätske-, elektrolyt- och syra-basbalans. I Näringslära för högskolan, Abrahamsson, L., Andersson, A., Nilsson, G (red.),160-179. Stockholm: Liber AB, 2013.

5. Burke, L., Deakin, V. Clinical Sports Nutrition. 5th ed. New York: Mc Graw Hill Education, 2015, 401-402.

6. Burke, L., Deakin, V. Clinical Sports Nutrition. 5th ed. New York: Mc Graw Hill Education, 2015, 776.

7. Burke, L., Deakin, V. Clinical Sports Nutrition. 5th ed. New York: Mc Graw Hill Education, 2015, 347-376

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