Posted by: Joe English | July 27, 2007

Training: Ten things you need to know about hydration

Hydration is one of the most important training topics for runners and triathletes. If you don’t properly hydrate, your performance is certainly going to suffer – and there are worse problems (like heat stroke, heat comas or even death) if you seriously get dehydrated. On the flip side, drinking too much fluid is not good either. Hydration is a careful balance of drinking the right amount and replacing what you need.

There is a ton of good information on the Internet about hydration, but a lot of it is quite technical. I thought I’d put together a simple, non-technical, 10 point list to cover the basics of hydration. I realize that there’s so much to write about on this topic that my 10 point list has 11 points on it, but these are things you should know.

So, while this is not supposed to be exhaustive or contain lots of technical guidelines, this list will give you a basic background on the issue. Think of this as a “hydration for dummies” list, rather than a technical manual.

Ten things runners and triathletes need to know about hydration

1. You need to be well hydrated before you start your run or workout. If you start partially dehydrated, it only gets worse from there.

2. The color of your pee should be pale yellow, rather than clear or dark yellow. It should look more like lemonade than orange juice.

3. How much you need to drink depends on how heavily you sweat. The more you sweat, the more you need to drink.

4. Electrolytes are lost along with fluid when you sweat. You need to replace these electrolytes through an energy drink, electrolyte solution or electrolyte tablets.

5. If you don’t replace electrolytes, particularly sodium, you won’t be able to absorb the fluid you’re drinking. This means that you could be drinking plenty, but not re-hydrating.

6. Dehydration leads to a loss of performance, cramps, digestive problems, and ultimately an inability to cool the body. These progressively worse problems will eventually stop you in your tracks.

7. Drinking too much plain water can also be a problem. Drinking lots of plain water can dilute the sodium level in your blood, leading to a problem called hyponatremia. This is why it is important to use a hydration product to replace electrolytes.

8. The term “drink to thirst” means that you should not drink just for the sake of drinking. You need to drink an amount of fluid that replaces what you’re losing in your sweat.

9. You may not actually feel “thirst” while running or racing. If you don’t ever feel the sensation of thirst, don’t make the mistake of stopping drinking completely. Continue drinking fluids in a moderate quantity to make sure that you’re getting what you need.

10. You should constantly be working to find the best method of hydration for you in your training runs. You need to learn how much you need to drink; what energy/fluid replacement drinks work best for you; and what it feels like to be well hydrated.

11. On race day, do what you’ve practiced in your training runs. Don’t try anything new. If the race supplies a hydration product that doesn’t work for you, make sure to carry your own drink in a fluid or powdered form so that you have what you need.

Feel free to ask questions by commenting on this page.

Coach Joe English, Portland Oregon, USA
Running Advice and News



  1. […] got a hang-over, you’re going to start your run dehydrated. And as I said in my column “10 things you need to know about hydration”, if you start out dehydrated, it just gets worse from […]

  2. Joe,
    Very good stuff. I’d like to add one caveat on items #4 & #5. It is true electrolytes are critical to performance and must be replaced. However, electrolytes are dependent on each other to a degree. Too much of one causes an imbalance in another. The rule of thumb is not to add any single electrolyte unless you have been clinically shown (medical or lab testing) to lose a single electrolyte faster than others. Then, your physician will prescribe the amounts you should take.

    Another thing to be wary of is self-assessment on one’s need of electrolytes. For instance, just because someone has that white crusty stuff dried on their skin after a workout, it doesn’t necessarily mean that they have lost “salt”. Another common symptom is muscle “cramping” but this symptom can be a caused by a number of different things (yes, electrolyte imbalance is one of them).

    The most current research still points to most of the commercially available sports drinks as the best way to go. They have been formulated for a balanced replacement.
    Coach Dean

  3. Ok,
    Try this hydration/dehydration conundrum out. Some researchers found that many elite marathoners (sub-2:10) actually lose more fluids and weight (by percent) than the slower runners in the race! Yet, their performance sure didn’t suffer!
    Coach Dean

  4. […] switching to bananas and PB&J sandwiches rather than energy gels to see if that helps. – Drink more fluid along with gels to ensure that you’re properly diluting the sugar in your stomach. – Cut out […]

  5. […] Issues – Diarrhea is both a symptom of, and a cause of, dehydration. [For more on this read this article.] Your experience – Younger and less experienced athletes tend to suffer more from GI problems […]

  6. […] in color. You’re likely drinking too much if your pee is colorless. (For more on hydration, click here.) 3. Eat plenty of carbohydrate rich foods – As with drinking, you can only sock away so many […]

  7. Your post about hydration and dehydration provides a real-life illustration that not all “drinking problems” are alcohol related. I especially liked the information about color of your pee. Seriously, thank you for the relevant, practical, and healthy information.

  8. […] Hydration tips for training January 1, 2008 — planetultramarathon… […]

  9. […] managed. You can read additional articles on this site about racing and training in hot weather and hydration basics to learn more about this important […]

  10. […] Ten things you need to know about hydration […]

  11. […] should be light yellow in color and you’re likely drinking too much if your pee is colorless. (More on hydration from Coach Joe […]

  12. […] should be light yellow in color and you’re likely drinking too much if your pee is colorless. (More on hydration from Coach Joe […]

  13. Again, really helpful! Great Posts!

  14. […] got a hang-over, you’re going to start your run dehydrated. And as I said in my column “10 things you need to know about hydration”, if you start out dehydrated, it just gets worse from […]

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