Water: Don't Workout Without It

By Erica K. Perkins, MS, a Fitness Director at the University of Virginia

Water is essential for any active person. Two-thirds of our total body weight is water. And it plays an important role in every major organ and system. To prevent adverse affects on the body, you should begin each workout fully hydrated.  

Why You Need Water
When exercising, we produce heat in our working muscles, which in turn, causes our core temperature to rise. The body cools down by perspiring, and as the sweat evaporates from the skin, our core temperature lowers. The water we lose through sweating comes from blood plasma. Plasma is how red blood cells get oxygen to our working muscles. Without sufficient water replacement while exercising, your total blood volume will decrease, compromising your blood's oxygen-carrying abilities. This may result in a drop in blood pressure and cause you to feel nauseated, dizzy or faint -- all symptoms of heat exhaustion. 

Continuing to exercise through heat exhaustion can lead to a heat stroke, which may cause a person's body temperature to reach above 106 degrees Fahrenheit. At this point, a person no longer sweats, and seizures, coma or even death may result if not properly and promptly treated.

During the dog days of summer, the high heat and humidity makes evaporation less effective, making you sweat more and lose greater amounts of fluid. That's why during summer, it's very important to pay attention to your hydration needs.

How Much Water Should I Drink?

If you are thirsty, you could already be dehydrated. As you sweat, blood volume decreases and the amount of salt in the blood increases. Since a part of your brain measures the amount of salts in your blood, it will send a thirst sensation to encourage more drinking to dilute the salts. 

Here's how to stay hydrated for exercise:

  • Drink 8 to 10 oz. of water before starting to exercise
  • Drink 3 to 4 oz. every 20 minutes during your workout. If you have the option to weigh yourself before and after your workout, it is recommended that you drink one pint of water for every pound that you lose. This applies whether you are exercising outdoors or indoors.
  • For workouts 1 1/2 hours or less, replenish with plain cool water.

Why Water Is Best

Sports drinks contain a lot of sugar and therefore have a lot of calories in them so be wary of their affect on your blood sugar levels and your daily caloric intake. Caffeinated beverages have long been labeled diuretics causing you to lose fluid. Even though recent research is investigating this claim, it is best to use plain water as fluid replacement. 

Here's how to stay hydrated everyday: 

  • Start your day with a glass of water. Drink something every two hours.
  • Choose breakfast items such as fruit and milk with cereal. These contain a lot of water and can contribute to your daily water intake.
  • Spruce up your water with a lemon or splash of juice for flavor.
  • Consume foods for lunch and dinner that contain water such as vegetables, fruits, yogurt and soup.
  • Check your urine, it should be pale in color rather than dark.
  • Carry water with you at all times.