Hydration for Athletes

Hydration for Athletes
Posted on 10/09/2019
Hydration for Athletes

By Chris Mathewson
Head Athletic Trainer, Ponderosa High School

I have spent 25 years caring for Ponderosa High School athletes and their opponents. One thing I am certain of is that few athletes understand the importance of hydration in athletic performance. It is not uncommon for me to talk to an athlete who is experiencing heat illness symptoms to find that they had less than 20 ounces of fluid the entire day. It is also not uncommon for more than half of that fluid to be drinks that actually hinder hydration.

A leader in research on athletic heat illness and proper hydration is the Korey Stringer Institute at the University of Connecticut.

From the Korey Stringer Institute's website:

Monitoring hydration status before, during and after exercise is essential for both performance and safety during physical activity. Maintaining an appropriate level of hydration (a euhydrated state) has been shown to increase performance (aerobic exercise, anaerobic exercise, strength, power), allows athletes to exercise at lower body temperatures and heart rates, improves cognitive function, and has been shown to enhance immunological function.

Dehydration is influenced by exercise intensity, environmental conditions (temperature and humidity), and availability of fluids during exercise. Once an individual loses 2% of their body mass from fluid losses impairments in performance are noticeable and these impairments become more extreme with greater levels of dehydration. [...]body temperature and heart rate increases over and above the levels of someone who is hydrated[...] can increase the risk of heat illness in dehydrated exercising individuals.

An appropriate hydration strategy involves athletes to begin exercise hydrated, minimize fluid losses during exercise, and then replace fluid losses after exercise. Hydration needs are individualistic, so athletes should be aware of their own hydration needs to maximize performance and safety.

Hydration Guidelines for Athletes*

Years ago, the Douglas County School District Athletic Trainer Group developed a simple one-page document explaining the importance of hydration for athletes. At the start of every sport season the athletic trainer is required to provide this document to each athlete and their parents.

Below are the guidelines we developed.

Before Exercise:
  • Drink water or sports drink throughout the day
  • 2-3 hours before exercise drink 17-20 oz of water or a sports drink
During Exercise:
  • Drink 20-40 oz of water or sports drink per hour of play (at least 5-10 oz every 15 minutes or amount equal to sweat or urine loss)
After Exercise:
  • Within 2 hours drink enough to replace any weight loss from exercise
  • Drink approximately 20-24 oz of water or a sports drink for every pound of weight lost
What NOT to Drink Before, During and After Exercise:
  • Fruit juices, carbohydrate gels, sodas and those sports drinks that have CHO levels greater than 8% are not recommended during exercise as the sole beverage
  • Beverages containing caffeine, alcohol and carbonation are discouraged during activity because they are not as effective as sports drinks in rehydrating the body
Warning Signs of Dehydration:
  • Thirst
  • Irritability
  • Headache
  • Weakness
  • Dizziness
  • Cramps
  • Nausea
  • Decreased Performance
Effects of Dehydration:
  • Dehydration can affect an athlete’s performance in less than an hour of exercise – sooner if the athlete begins the session dehydrated
  • Dehydration of just 1% - 2% of body weight (only 1.5 – 3 lbs. or a 150 lb. Athlete) can negatively affect performance
  • Dehydration of greater than 3% of body weight increases an athlete’s risk of heat illness (heat cramps, heat exhaustion, heat stroke)

* Recommendations from the Gatorade Sports Science Institute based on the National Athletic Trainers Association Position Statement, Fluid Replacement
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