Hydration and Exercise, Part I: Water or Sports Drinks?

As a coach and personal trainer, I’m always asked about sports drinks and whether they are healthy. Sometimes, the question is phrased as, “Should I drink a sports drink or water when I workout?”

There isn’t one universal answer to that question. Each individual is different in their nutritional needs. Not to mention the other things you should consider, such as cost, taste preference, and accessibility.

Water

Drink water when training at a moderate intensity for less than an hour. How much should you drink?

• First, drink at least 8 ounces one hour before working out (about half a bottle of water).
• Weigh yourself before and after exercising. Drink 10 ounces of water for every half pound lost during exercise. Nearly all weight loss in exercise comes from sweat and breathing (you exhale water when you breath). This should all be replaced and not counted as weight lost in a weight loss program.  Weight loss from fat comes through a period of several weeks or months consisting of resistance training and cardiovascular training and a sensible diet, not from a single exercise session.
• If you are training for 30 minutes or more, drink a minimum of 5 ounces of water every 20 minutes.
• If you are training at a high intensity level, drink 6-12 ounces of water every 15 minutes.
• If you are working out in high heat and humidity, drink 6-12 ounces every 10 minutes.

Sports Drinks 

Drink sports drinks only if you are training at a moderate intensity for more than an hour or are training at a high intensity level. How much is that, though?

If you choose to go with a sports drink, never rely exclusively on the sports drink as your sole source of hydration. You have two choices:

1. Mix 8 ounces of water with 8 ounces of your choice of sports drink.
2. Pre-hydrate with water – at least 8 ounces one hour before working out.

Training at this rate of intensity and/or at this duration will cause you to lose some electrolytes and burn a lot of calories. Fatigue will set in, and if you don’t hydrate, you’ll feel faint and dizzy.

Sports drinks provide 50-60 calories in an 8-ounce serving, providing you with an extra boost during your workout. It also contains electrolytes, as every sports drink commercial reminds us.

While you lose some electrolytes, it is not necessary to replace this immediately with a sports drink. Most people will get plenty from a well balanced diet of lean meats, whole grains, fruits, vegetables and dairy.

To be continued… (Coming up next: Chocolate Milk, Fruit Juice and Caffeine.)

If you have a specific question related to fitness or health, please email me (coachsabin@gmail.com) and I'll feature it in an Ask The Trainer blog post.