5 Hydration Mistakes that Could Degrade Your Performance and Impair Your Health

This post explains how to avoid making five big mistakes with your pre-workout hydration.


Hydration is crucial for athletes. Screwing up your fluid intake not only reduces your performance, it can endanger your health.

When we exercise, our muscles produce heat and our body's core temperature rises. In an effort to cool itself off, the body sends the warm blood from the core out to blood vessels closer to the surface of the skin. This warm blood signals our sweat glands to release sweat. As air moves over the surface of the skin, sweat evaporates, pulling heat off the skin. This cools the blood in the vessels right below the skin, and this cooler blood travels deep inside our body to cool our core.

When we exercise in high temperatures and humidity, it is difficult for our sweat to evaporate, which means that the blood in the vessels just below the surface of the skin is still warm when it returns to the core. The body responds by sending more and more blood to the skin in an effort to cool it. As a result, less blood flows to exercising muscles. Performance suffers because the exercising muscles are receiving less oxygen and nutrients through the blood. In addition, if your core temperature continues to rise, you are at a high risk for heat cramps, heat exhaustion and heat stroke.

Avoiding these five mistakes will keep your core temperature cooler during exercise, which will allow you to train hard and stay safe.

1) "I Don't Want to Slosh!"

Many athletes don't drink enough before exercise because they don't want to feel fluid sloshing around in their stomachs. But exercising in a dehydrated state will prevent you from training at your best and can put you at risk for heat-related illnesses. Avoid that with these tips:

  • Drink 17-20 ounces of water two to three hours before exercise. If you weigh more than 210 pounds, drink five to 10 more ounces
  • Drink seven to 10 ounces of fluid 10 to 20 minutes before exercise
  • Practice your pre-hydration strategy during training so that your body knows what to expect before competition

2) "What Is My Sweat Rate?"

During exercise, your goal is to replace the fluid you are losing. The problem is that many athletes have no idea how much fluid they're losing. Weigh yourself before and after exercise. Then calculate your sweat rate with this calculator. Your sweat rate will change with different types of exercise in different environments and at different altitudes. Calculate your sweat rate often to develop the best hydration strategy for every situation.

Learn how to estimate your sweat rate.

3) "I Have a Headache! I Need Medicine!"

Many athletes ignore the fact that a headache is a sign of dehydration. Other common symptoms include excessive thirst, dark-colored urine in the morning, dry skin and muscle cramps. Many athletes take Ibuprofen, Advil, Aleve or Aspirin to cure headaches. These non-steroidal anti-inflammatory medications (NSAIDs) may interfere with the body's ability to retain sodium during endurance training. Sodium is very important for maintaining fluid balance in the body, and losing too much of it may cause muscle cramps.

4) "H2O Only Please!"

It is not uncommon for an athlete to lose a liter of sweat per hour of exercise. Sweat contains not only fluid but an average of 1035 mg of sodium, 1065 mg of chloride, 195 mg of potassium, 40 mg of calcium and 19 mg of magnesium. Electrolytes are important for fluid balance, muscle contraction and more. Most of these electrolytes are replaced through a healthy diet. However, long, intense exercise in the heat requires a drink or food during activity to replace lost electrolytes.

5) "I'm Done."

Along with protein and carbohydrate, fluid isĀ an important part of every recovery nutrition plan. After exercise, we need to drink 16 to 24 ounces of fluid for every pound lost during exercise. Getting caught up in a post-competition celebration often prevents athletes from practicing good recovery nutrition. Don't forget that what you do after training or competition today prepares you for tomorrow.

We are in the midst of summer, and athletes are exercising outdoors where air temperature and humidity may be very high. Now that you know the science behind how the body cools itself, you understand that consuming fluid allows us to sweat and cool our core temperature. Keeping the core temperature low is the secret to performing at a high level and avoiding heat illness. Avoiding hydration mistakes will put you a step ahead of your competition this summer and leave you in top condition for fall tryouts.

References: Skolnik, H., Chernus, A. Nutrient Timing for Peak Performance: The right food, the right time, the right results. Human Kinetics. 2010

Photo: Uconn.edu

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