Health

The Importance Of Water Hydration During Exercise

September 19, 2009
By J White

Most people realize that when they exercise, they need to drink water to replace the fluids lost by sweat. This is evident by all the water bottles that accompany gym members during their exercise sessions.

However, their is a belief among many exercise enthusiast that drinking water can impede your performance. This belief could not be further from the truth. The fact is that not replenishing your body of water during exercise can diminish your ability to exercise.

According to Dr. Michael N. Sawka, an expert in thermal physiology at the United States Army Research Institute for Environmental Medicine, water loss that resulted in as little as a 1 percent drop in body weight (1.5 pounds for a 150-pound person) declines exercise performance by 20 to 50 percent.

This is because sweat loss during exercise results in dehydration. Since your blood is composed primarily of water, dehydration causes a decrease in blood volume. This decrease in blood volume lowers your blood pressure and, as a result, reduces blood flow between your muscles and skin.

To compensate, your heart rate increases to make up for the loss of blood flowing throughout your body. However, less blood is still reaching your skin. This results in heat loss being reduced and your body overheating, and like a car engine running hot, reduces your ability to perform, leading to premature exhaustion.

In reality, the only way to truly compensate for this is to drink water to replace lost fluids. The only question that remains is how much should you drink.

How Much Water?

Adequate hydration actually starts before you exercise. The recommended amount to drink is 8 ounces every hour. Any more is likely to be lost to urination. However, if you do not have to urinate within an hour, drink about 4 to 8 ounces more. When you do start to exercise, drink about 6 to 12 ounces every 15 to 20 minutes, especially when exercising in the heat.

Also when you drink the water, you want it to be absorbed quickly into your blood stream. To accomplish this, the water should be cool — about 40 to 50 degrees Fahrenheit (4.5 to 10 degrees Celsius) — but not ice cold.

As far as beverages with caffeine, the caffeine can increase muscle action, but Dr. Sawka says that drinking a lot of caffeine before exercising could start you out dehydrated. This is because caffeine is also a diuretic. And since alcohol is also an diuretic, you want to avoid it as well. If do drink alcohol the night before, drink two cups of water before you go to bed and another two when you get up in the mourning.

To sum it up, water hydration is important not only during exercise, but before you start to exercise as well. By staying well hydrated, you are able to exercise at a higher level for a longer period of time. This higher exercise performance will allow you to increase your endurance, and if you are following a weight loss plan, burn more calories.

Source:
nytimes.com/specials/women/warchive/960612_1274.html, Personal Health: Drinking Enough Water
simplefitnesssolutions.com/articles/sweating%20.htm, Sweating — Your Body’s Cooling System

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