Hydration

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Hydration is key to sports nutrition success

What is the big deal about hydration?

A hydrated athlete is a healthier and more productive athlete. Even small drops in body fluid levels can have a negative impact on your health and performance.

Early signs of dehydration begin with lack of concentration and increased body temperature (1% body weight loss), then progress to decreased performance (3% weight loss), to cramps, chills, nausea, and a rapid pulse (5% weight loss). More danger comes with headaches, dizziness, stomach cramps, which are characteristic of heat exhaustion (>5% weight loss). Heat stroke includes increased body temperature, no sweat or urine, dry tongue and an unsteady walk. Seek medical attention in these latter stages of dehydration. It�s no joke�dehydration is dangerous. For a 120# woman, dehydration starts with as little as a 1# weight loss.

Fluid goals are important in your sports nutrition plan!

Are there any simple ways to test for dehydration?

Other than having your blood drawn, two tests you can do on your own include the urine test and the weight check. First thing in the morning, check the color of your urine. It should be pale (light in color like diluted lemonade or straw). If it is yellow-gold (like apple juice) or darker, you are dehydrated. (Some vitamins cause urine to be a bright glow-in-the-dark yellow. This unnatural color is not related to your hydration).

The other test is to check your weight before and after a workout/event. Ideally, weigh yourself first thing in the morning after you go to the bathroom and before you drink or eat anything. Hydrate as usual before and during your training. After the session, weigh yourself without clothes again. Do this caculation:

Sweat Rate per Minute Calculation:

(start weight in pounds X 16 to get your weight in ounces) - (ending weight in pounds x 16 to get your weight in ounces) + (number of fluid ounces your consumed) - (estimated ounces of urine you released) = (Weight change in ounces, which will be ounces gained or ounces lost in the session). Then, take (weight change in ounces) divided by the (number of minutes of your training session). This will give you your estimated sweat rate per minute.

What do I do with my "sweat rate per minute"?

Your sweat rate is used to dtermine how many ounces you should be drinking per minute of a typical training session. For example, if you lose 3 pounds in a 120 minute session, drank 16 ounces of fluid and did not urinate, your weight change is 64 ounces. Over 120 minutes, your sweat rate per minute is .53. Now, .53 x 60 minutes means you need to drink 32 ounces per hour (8 ounces every 15 minutes). You'll want to do this test several times to get an average sweat rate for the season you're in. Obviously, if you weigh with clothes and don't keep track of your fluid intake and urine output the results will be less than accurate. However, you should still weigh yourself before and after training as often as you can. You'll get the general idea if you're under- or over-doing it with fluids.

What do I do if my weight changes during a training session or event?

Body weight changes at the conclusion of a training session or event are hydration changes, not fat loss (that occurs over time). Your goal is for your finishing weight to be about the same as your staring weight. If you lost weight, a general rule is to replace 20-24 ounces of fluid for every pound lost. This could be a lot to replace, so it is best to hydrate before and during an event to maintain your fluid levels, with maybe only a slight need to catch up afterwards. A goal is to have your weight return to normal within 6-8 hours of the training session/event. If you gained weight, you drank too much, and should adjust (reduce) your intake during the next training session.

The last point is to never rely only on thirst as a hydration indicator�thirst is not always accurate. If you are thirsty and have dark colored-urine and/or weight loss, dehydration is likely.

Check out how to use sports drinks , how to time your fluid intake , and hydration in everday sports nutrition.