Hydrating, It’s Complicated.

Staying hydrated is essential to being able to sustain a good pace on race day. Too much or too little water can cause serious problems for runners. Maintaining optimal hydration is more complicated than we’d all like.

There are many factors that play a role in your hydration during training and races. We all hear the pervasive message of 8 glasses of 8 oz of water a day, but is that right for everyone? It’s not even close. It’s difficult to calculate exactly how much fluid a person needs each day. Some factors that impact your recommended fluid intake are: the type of food you eat, your activity level, your body fat percentage, and your acclimatization to the heat.

Another recommendation we hear a lot is to drink to thirst, but once again the phrase, “it’s complicated,” rears it’s head. When you’re exercising, especially for extended periods of time, your body may not signal you to drink because of imbalances in your system. You need to be looking at other objective measures such as the amount of fluid you are taking in, the temperature, the color of your urine (we’ll talk about this more in a few paragraphs), and any GI issues you’re having.

You’re unlikely to need to hydrate during a 5k or 10k event. For a 1-2 hour run, you’ll need water, but not electrolytes. If you’re running five plus hours, you’re going to need some form of electrolyte replacement strategy. If you’re between the 2-5 hour range, water is necessary and electrolytes would be helpful but are not necessary like they are after 5-6 hours. Electrolytes are helpful in the 2-5 hour range because they help you hold onto the water you’re consuming rather than it just going straight through you.


Most ultrarunners use some type of electrolyte supplement during training and in races. There are lots of options as far as different sports drinks, powders, and tablets/capsules. It’s likely that you’ll want a variety of options when you’re racing because things change and some times something that has worked throughout training suddenly stops working. Sports drinks usually do double duty by providing you with both carbohydrate and electrolytes, so make sure you have options for both when the drink doesn’t work so well. Aid stations typical fare will consist of foods with both carbohydrate and with sodium, the main electrolyte you need, so keep a mental note that you’ve taken in some electrolytes there too.

After a run or a race, there’s no need to ingest a sports drink to replenish your electrolytes. Your body will be able to balance it out within the next 24-48 hours. If you have another run within that time frame, however, drinking a Gatorade is probably a good idea.

One way runners often judge their hydration is through urine color. The problem is there are a lot of things that impact your urine color, so it’s not always the most accurate. You can have clear urine because your body doesn’t have enough electrolytes to hold onto the water so it just spits it back out. The best time to judge hydration with urine color is when you first wake up in the morning because it’s had time to accumulate. The first urine in the morning tells you about your hydration the day before. So if you track your hydration and exercise, you’ll get a good idea of what your body needs for different workouts.