Sports Nutrition Hub Update: September 2009

Timely Topic: Fighting the heat

For athletes, optimal hydration must be a key focus, especially this time of year. Dehydration allows the body to heat up faster and can significantly impair sports performance and health. Dehydration also increases the risk of heat illnesses such as heat cramping, heat exhaustion, and heat stroke. Even a small amount of fluid deficit (losing 2% of body weight, which would be 4 pounds for a 200-pound athlete) in a workout or competition can affect performance. In hot and humid environments, fluid losses can occur very quickly. Help athletes learn their individual sweat rate — and improve their hydration habits — by weighing them before and after exercise.

Use an individualized HYDRATION PLAN to help athletes properly hydrate. Below are some tips to share with your athletes:

  • Start drinking fluids as soon as you wake up. Start with 16 ounces of water.
  • Keep a fluid bottle with you so you can drink throughout the day.
  • Drink extra fluids with meals, such as 100% juice, skim or 1% milk, or smoothies.
  • Two hours before workouts, add at least 20 ounces of extra fluids. Sports drinks may be a great choice during this time, especially if you need the extra calories or find yourself cramping during exercise.
  • Continue to sip fluids regularly right up to workout time.
  • Maximize hydration during workouts and competitions. Try to drink at least 6 ounces of fluid every 15–20 minutes of training.
  • After workouts, drink at least 24 ounces of fluid for every pound you lose during exercise.
  • Always keep an eye on urine color and volume to monitor your hydration status.

Remember: well-hydrated athletes concentrate, execute, and perform better than dehydrated athletes!

For more information on hydration and preparing for preseason workouts, check out Keys for Performance or High School Fuel

New Research Hydration issues in real-life athletes

At the June, 2009 meeting of the National Athletic Training Association (NATA) in San Antonio, Texas, several researchers presented findings on hydration and electrolyte issues. The following three studies involved actual athletes participating in real athletic endeavors. Results provide us with some important reminders as we enter hot pre-season workouts.

Study 1 (Stearns et al.) evaluated running performance and pacing ability in well-trained distance runners while they were in hydrated vs. dehydrated states. They reported that runners ran the interval race faster when they were hydrated. Hydrated runners were also better at evenly pacing intervals.

So…

  • Remind athletes that even mild dehydration can affect performance significantly.
  • Promote proper fluid intake before, during, and after running workouts.

Study 2 (McDermott et al.) demonstrated that 12 to 14 year-old kids participating in a 5-day summer soccer camp were likely to arrive at practice and game sessions poorly hydrated; males more so than females. Kids who were exposed to 5-minute hydration education sessions drank more fluid during practice than those who were not.

So…

  • Help athletes pre-hydrate and re-hydrate.
  • Remember that a small amount of education can make a big impact on athletes’ performance and safety.

Study 3 (Kopec et al.) evaluated whether or not there was a difference in sweat sodium losses between black and white college and NFL football players. They found no differences based on race, but did note high sodium loss in many athletes, with an average of 1,920 mg of sodium lost PER HOUR of practice! One player lost 3,880 mg of sodium per hour!

So…

  • Educate athletes that they likely require more daily sodium than non-exercisers to replace the high amount lost in sweat. The daily “limit” of 2,000 mg PER DAY is inadequate for athletes practicing in the heat.
  • Encourage consumption of salty foods and beverages, adding salt to foods, and the use of a sports drink that contains sodium during intense and hot workouts.

*Note: These studies were published in abstract form only in the Journal of Athletic Training. For complete references and abstracts, download this PDF.

Practical Point: Foods to Hydrate

Sometimes athletes have a hard time drinking the quantities of fluids they need to stay hydrated – or replenish fluids lost in hard workouts. These “Top 10” foods high in fluids can help athletes meet their needs – plus get added nutrients. All of these foods are at least 80% water!

  • Cucumbers
  • Lettuce
  • Watermelon
  • Tomatoes
  • Melon
  • Onions
  • Peaches
  • Yogurt
  • Oranges
  • Applesauce

For more information on hydration and foods that can hydrate, check out 101 Sports Nutrition Tips