Hydrating on Long Activities

Summer, Fall, Winter, Spring, no matter what the season, we have to hydrate when we exercise. But how do we know WHAT to use and and HOW MUCH to drink.

In general, we want to hydrate based on our exercise duration about 3-6 ounces of water every 15-20 minutes. For a short activity on a moderate to cool day that lasts less than an hour, you may not need to drink anything during, as long as you go into the activity hydrated, it isn't a high intensity activity, and you drink soon after.

However for activities longer than 30 minutes, for high intensity, or in warm to hot weather, hydration is absolutely essential!

How Much

How much can be determined three ways:

How often do you feel thirsty? The body has a great system for telling you it needs fluid. You feel thirsty! When you feel thirsty, drink. If you don't, don't. Previously we were told that if we felt thirsty we were already dehydrated. However, recent studies in hydration show that thirst is the best indicator for need for fluid, and actually taking in too much water while exercising can be dangerous.
If you often DON'T feel thirsty, and in some situations you may not, or some people don't feel it until they ARE dehydrated, drink 3-6 ounces every 15-20 minutes. In hot weather, add an additional 20 ounces before you start so you're well hydrated, and drink at the higher end. Fortunately on a long distance run, each water stop is 2 miles apart so you can depend (on a well supported race) on water right at the right time.
Determine your individual needs doing a sweat test. Some of us sweat MORE than others. Some less. In the human body there are generalizations, but often not absolutes. If you're doing long distance endurance exercises, this is the BEST way to figure out how much you should take in.

What is the best method for calculating the amount of fluid a person needs during exercise?

Baseline fluid requirements for non-exercising individuals can be calculated by weighing the person in lbs and dividing that number by 2:
- Wt (lbs) divided by 2 = minimum daily requirement of fluid for a non-exercising individual represented in ounces
- Example: 140 lb male
- 140/2 = 70
- 70 ounces fluid replacement necessary for daily maintenance. This is what you should drink on days you don't exercise.
Exercising individuals need to build on the minimum daily fluid requirement. The most accurate method for determining fluid replacement for an exercising adult is by weighing themselves before they run and weighing themselves again after they run. The change in weight represents the amount of fluid necessary to achieve an accurate fluid balance.
1. Example: 140 lb male
2. Pre-exercise weight: 140 lbs
3. Post-exercise weight: 139 lbs
4. 1lb of weight loss = 16 ounces of fluid to be replaced
5. This is in addition to the minimum daily requirement

What?

For short exercise, nothing more than water is needed. Sports drinks contain large amounts of sugar, sodium, and potassium. That's not a bad thing, but in a short workout it is an unnecessary thing. Sports drinks aren't for daily intake, and shouldn't be given to kids as a "juice" due to the high sugar/sodium content, unless the child is exercising. While sports drinks do have electrolytes, which often must be replaced when a child has stomach flu resulting in diarrhea and vomiting, pediatricians do not recommend sports drinks due to the high sugar content, which can further aggravate the stomach. Use Pedialyte (which can also be used by athletes, but is pretty expensive at the amounts we need), instead.

If you're exercising more than an hour, then you need to replace not only water, but also the electrolytes you're losing in sweat. That means taking in either a sports drink with carbs (sugars), sodium, and potassium OR drinking water, and taking in fuel replacement ins the form of gels (Gu, Power Gel, Accel Gel, etc.). Note, if you want to just do water and food, you MUST take in electrolytes along with them. Food, even candy, doesn't have enough of the right electrolytes in the amount you'd take in during a workout unless you create it that way.

Why Electrolytes and What are They?

When you sweat your body gives off water, sodium, and potassium. In addition, if you're hydrating appropriately you will lose more in urine. (If you're working out for a long period and you're NOT urinating, you're not drinking enough.)

Electrolytes are essential for life. They are electrically charged ions that maintain the voltage across cell membranes. In short, if you "run out" you run down. Lack of electrolytes can lead to lethargy, confusion, and even death. So hydration and fuel replacement is no small matter!

What if I Can't STAND Gu or Sports Drinks?

Don't worry! There are other options if you can't stomach one more Gu or Sports drink on a long activity! When I ran a 9 hour race in 90 degree weather, there was NO way I was drinking Gatorade and Gel for 9 hours. I got tired of it, and frankly it wasn't enough to keep up on my electrolytes.

Salt is great. Just plain old table salt has potassium chloride and sodium. I dipped boiled potatoes into salt (and I mean DIPPED) and ate them when I noticed that my fingers were swelling, which is an indication of low blood sodium.

In addition we all used electrolyte caplets, such as Endurolytes, S-Caps. These are small, easy to swallow gel capsules that contain sodium and potassium.

I also used Nuun, which is a no/low calorie additive that can be put right into your water bottle. It doesn't have high flavor, and it's refreshing when stomach issues hit.

I've had runners in the past tell me that they don't need to drink when they run, and I've come to the point where if you run with me, you are REQUIRED to take water on anything over 5 miles. It's a dangerous gamble to go out, even on a cool day, without a source of liquid. Don't gamble! Learn YOUR hydration needs, figure out what combination of water/fuel/electrolytes work for you, and you won't be sorry. Don't...and you will.