Sports Drinks and Hydration

by Stephanie Nunes, RD

Maintaining adequate hydration during physical activity is one of the most important nutritional methods to optimize performance.


How much fluid do I need with exercise?

Due to the wide disparity in body size, activity and environmental conditions, there is no one fluid recommendation that will suffice for everyone. In fact, the 2007 American College of Sport Medicine (ACSM) position stand on hydration recommendations are as follows: "Due to individual differences in sweat rate, it is difficult to provide a single hydration recommendation".

What is "sweat rate"?

To determine your own sweat rate, simply weigh before you exercise and after. For every 1% of body weight lost, you should replace with 16-24 oz fluid. The goal is to ultimately minimize loss of body weight (i.e. dehydration), but to avoid taking in too much fluid during exercise.

How do I know if I'm staying hydrated throughout the day?

  • Frequent urination
  • Lemonade colored urine

Why is it so important to stay hydrated?

Studies show that athletes who enter competition in dehydrated states, have decreased performance. During competition a 1% drop in hydration/body weight may cause a 3-4% decline in muscle performance.

Should I be drinking sports drinks or water?

For exercise longer than 60 -minutes, sports drinks are recommended. Some researchers even suggest that there are benefits to using sports drinks for exercise over 30-minutes.

Why are sports drinks better than water during exercise?

  • Sports drinks taste better and encourage hydration.
  • Provide carbohydrate fuel for the muscles and brain
  • Provide sodium to help the body retain more fluids.
  • Allow the athlete to exercise longer.
  • Prevent hyponatremia, or water intoxication. When athletes consume too much water over a period of a few hours, they can lose significant amounts of potassium and sodium, which can lead to symptoms that mimic severe dehydration.

Which sports drinks should I use?

The best sports drink is the one that you like to use the most! If you perspire heavily, you might consider a higher sodium sports drink like the ones listed below. Some sports drinks contain carbohydrate and protein. Whichever formula you choose, it is important to try it out several times in training before using it on race day.

Hydration Guidelines Pre-Exercise or Race:

  • Drink 16 oz sports drink 2 hours before training, which should produce a light-colored, but not clear urine
  • Drink 8-16 oz sports drink 15 minutes before training or race.

Hydration Guidelines During Exercise or Race:

  • Determine "sweat rate" and use as a guideline.
  • Try to drink 5-8 oz every 15 minutes rather than large amounts at one time.
  • When eating carbohydrate foods such as gels, try to drink water with these items vs. sports drinks.

Hydration Guidelines after Exercise or Race:

  • Drink 16-24 oz for every pound lost during exercise

Examples of Sports Drinks:

Gatorade, Edge Energy, GU20, Cliff shot electrolyte, HEED, First Endurance EFS, Motor Tabs, E-fuel. Drinks containing extra sodium are: Gatorade Endurance, PowerBar Endurance, First Endurance EFS, E-load, Hydro Cooler. Drinks with added protein are: Accelerade, Revenge Pro, Perpetuem.

Keep in mind that sports drinks should not be diluted, and you shouldn't add more powder to water than the instructions suggest. They're formulated to provide energy in the right amount and concentration for optimal performance without causing gastrointestinal distress.

Stephanie Nunes is a registered dietician with over 14-years experiece in the field of nutrition. She has a private practice in San Luis Obispo, CA called "Rock Solid Nutrition". You may reach Stephanie at: rocksolidnutrition@sbcglobal.net