Hydration for Young Athletes

Improving performance while reducing the risk of injury and serious illness

By Chad LaChance, PT, DPT, ATC, CSCS

It’s hot out there in most areas of the country right now and many of us aren’t taking the proper measures to make sure we can hold up against the heat. This is especially important for our young athletes participating in outdoor sports. Maintaining proper hydration doesn’t only reduce the risk of serious injury or death, but it can help boost performance while reducing the risk of an orthopedic injury.

Why is Hydration Important?

Internally, our bodies consist of 65% water! Our blood relies on proper amounts of water to remain at optimal consistency for pumping blood and regulating our blood pressure. Our muscles rely on water to allow them to use energy efficiently and deliver oxygen and nutrients to working muscles. Without this, we wouldn’t be able to meet the increasing demands of physical activity and sport. Our brain is 85% water. An athlete’s ability to concentrate and be alert during sport rely on adequate amounts of water in the brain. When some or all of these are affected, the risk of injury increases substantially.

Numbers to Remember:

50% : Approximately 50% of all athletes (youth through professional) report to sport inadequately hydrated; this can lead to muscle cramping, muscle fatigue decreased alertness and ultimately injury.

2% : A 2% loss in body weight through sweating causes the body to experience increased fatigue, reduced endurance, declining motivation and beginnings of heat-related illnesses. It’s recommended that you limit weight loss to <2% through adequate hydration before, during and after activity.

16 oz : Athletes should replace every pound of body weight lost after activity with at least 16 ounces of water for proper re-hydration.

Signs of dehydration

  • Dark colored urine
  • Decreased frequency of urination
  • >2% loss in body weight pre vs post exercise
  • Dry mouth, extreme thirst
  • Dizziness, light headedness
  • Lethargy

Preparing for Activity in the Heat

Before a workout or competition, properly hydrate by drinking 1 to 2 cups of fluid an hour before startingone cup about 15 to 30 minutes prior and then 5 to 10 ounces of fluid every 15 to 20 minutes of activity. These amounts can be adjusted based upon heat index and the amount the individual sweats (ie: sweat rate)

How to Monitor Hydration

Monitor urine color: Well-hydrated persons will have clear to light yellow urine; dark colored urine indicates hypohydration.

Calculate Sweat Rate: There’s no cookie-cutter approach to hydration. Each athlete should consider their individual sweat rate to assist in preparation and rehydration. Sweat rate is the amount of fluids lost during a workout. To calculate sweat rate:

Body Weight (before exercise) – Body Weight (after exercise) + any fluids consumed during workout = Sweat loss

Sweat Loss / Exercise time = Sweat Rate (mL/min or mL/hour)

Online Sweat Rate calculator

Know the signs of dehydration and measures to help prevent it! Keep our young athletes healthy and in the game!

For more information please visit: https://ksi.uconn.edu/prevention/hydration/


McDermott, Brendon P., et al. (2017) National Athletic Trainers’ Association position statement: fluid replacement for the physically active. Journal of Athletic Training 52.9: 877-895.

Casa, Douglas J., Priscilla M. Clarkson, and William O. Roberts (2005). American College of Sports Medicine roundtable on hydration and physical activity: consensus statements. Current sports medicine reports 4.3 115-127.

Judelson, D. A., Maresh, C. M., Anderson, J. M., Armstrong, L. E., Casa, D. J., Kraemer, W. J., & Volek, J. S. (2007). Hydration and muscular performance. Sports medicine37(10), 907-921.