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Staying Healthy During Practice and Competition

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What is Dehydration?

  • Losing 2% of your bodyweight through sweating
    • A 150-pound person losing 3 pounds of water from sweat = dehydration
  • Dehydration also increases body temperature and heart strain

How Much Water Should I Drink Per Day?

  • There is NO EVIDENCE to support “8 glasses of water per day”.[2]
  • Instead:
Your bodyweight (in ounces) / 2 = Optimal Water Intake

  • ALSO, drink 25% of your total intake first thing in the morning.

How can I stay hydrated?[3]

  • Before: 5–7 milliliters per kg of bodyweight 4 hours before exercise/competition
    • If you weigh 150 pounds (68 kg), drink up to 476 milliliters (16 oz.)
  • During: Drink 30–60 grams of carbohydrate per hour.
  • After: Drink 1.5 Liters (6 cups) of water for each kg (2.2 lbs) of body weight lost.

More is not better

  • Drinking more water than is recommended will not improve performance and “provides no clear physiologic or performance advantage”.[4]

How much of the different sports beverages should I drink?

  • Using the 30-60 grams carbohydrate per hour recommendation, here is how much to drink of the 4 most common sports drinks:

oVitamin Water: 1 small bottle (16-oz) per hour

oSmart Water: There are no carbohydrates in Smartwater, but it does contain electrolytes (sodium and potassium) and is best when exercising < 1 hour.

oCoconut Water: “Mother Nature’s Gatorade” = 1 container (8-oz) per hour

oGatorade: 1 small bottle (16-oz) per hour


1.Nybo, L. and B. Nielsen, Hyperthermia and central fatigue during prolonged exercise in humans. J Appl Physiol, 2001. 91(3): p. 1055-60.

2.Valtin, H., "Drink at least eight glasses of water a day." Really? Is there scientific evidence for "8 x 8"? Am J Physiol Regul Integr Comp Physiol, 2002. 283(5): p. R993-1004.

3.Sawka, M.N., et al., American College of Sports Medicine position stand. Exercise and fluid replacement. Med Sci Sports Exerc, 2007. 39(2): p. 377-90.

4.Kavouras, S.A., et al., Rehydration with glycerol: endocrine, cardiovascular, and thermoregulatory responses during exercise in the heat. J Appl Physiol, 2006. 100(2): p. 442-50.

Have A Question About Hydration / Nutrition?

Call (631-352-7654) or email ([email protected]) Dr. Arnold!