Hey Coach: Why Are You Always Telling Me To Drink Water During Practice?

By Dana Monsees

water_bottleWater is an essential, yet commonly overlooked part of a successful swimming training program. It becomes even more important during summer swim team season, when we sweat much more during training outside in the sun, than we do inside. But why is water, and hydration in general, so important for athletes, and swimmers in particular?


Dehydration is a big deal. It can negatively impact energy levels, training, and performance, and can increase the risk of heat injury (like heat stroke, or heat exhaustion) during the summer. Many swimmers (especially younger swimmers) do not realize how much water they are losing through sweat, since they are surrounded by water during training. Further, young swimmers become dehydrated much faster than adults: since they are smaller, their core temperature rises faster, and we must take extra care to make sure they stay hydrated (Link).


But can it really affect your training that much? Yes! Dehydration can reduce the body’s capacity to do work by about 30%. This means, if you were hydrated, you could do 30% more work than if you were dehydrated. You know how it feels when you hit that wall halfway through practice? It could be because you’re dehydrated. This effect of dehydration is made even worse in aerobic athletes when as little as 2.5% body weight loss due to dehydration turns into a 45% decrease in exercise performance. (Link) Yikes!


The best and easiest way to keep track of how hydrated or dehydrated you are is…you guessed it, the color of your urine. The ideal is to have a consistent pale yellow urine color. The darker color your urine is, the more dehydrated you are, and the more it will negatively affect your swimming performance. If it’s clear, you may be over-hydrated, which isn’t necessarily a good thing either. Athletes should not rely on the thirst mechanism (how thirsty you are) to determine when to drink, as it is “not an accurate indicator of how much fluid an athlete has lost.” (Link). Another easy way to monitor hydration is to weigh yourself before and after practice, then to replenish the amount of pounds lost with the same amount of water (about three cups of fluid for each pound lost during training).


So, what should we do to stay hydrated?

 For starters, bring a big water bottle or sports drink to every single practice.

water-bottlesFor practices of an hour or less, you’re fine with sipping on water to stay hydrated. Any longer than that, (especially if it’s outside!), you’re going to need something extra to give you enough energy to get your through, like a sports drink, which is fortified with electrolytes and potassium to replace essential nutrients you’re losing through your sweat. If you don’t like the taste of gatorade, you can dilute it with water, or try something else like coconut water, powerade, etc. The American College of Sports Medicine recommends athletes drink “3-8 fluid ounces of water every 15- 20 minutes when exercising for less than 60 minutes,” or alternatively, if training is longer than an hour, to drink “3-8 fluid ounces of a sports beverage (5-8 percent carbohydrate with electrolytes) every 15-20 minutes.” Athletes should be drinking water throughout the day before and after training. The bottom line: always keep a water bottle with you (especially during practice!), if it’s a long practice, make it a sports drink, and if you feel really thirsty, you’re already dehydrated!


 Jeukendrup, A., & Gleeson, M. (2010). Sport nutrition: An introduction to energy production and performance (2nd Ed.). Champaign, IL: Human Kinetics.

 “Parents and Coaches’ Guide to Dehydration and Other Heat Illnesses in Children.” (2003) National Athletic Trainers Association for the National Safe Kids Campaign. http://www.nata.org/sites/default/files/Heat-Illness-Parent-Coach-Guide.pdf.

 “Selecting and Effectively Using Hydration for Fitness | ACSM.” 2011. American College of Sports Medicine. https://www.acsm.org/docs/brochures/selecting-and-effectively-using-hydration-for-fitness.pdf.

 TrueSport Nutrition Guide. US Anti-Doping Agency (USADA), 2013. http://www.truesport.org/library/documents/resources/nutrition_guide/NutritionGuide.pdf

 Thirsty for more? Check out these articles for more information on hydration!

 Refueling and Rehydrating after a Workout, USA Swimming

8 Nutritional Recommendations for Swimmers, SwimSwam

Parents and Coaches’ Guide to Dehydration and Other Heat Illnesses in Children, National Athletic Trainers Association

Top 5 Beverage Choices for Swimmers, USA Swimming

Stay Hydrated, USA Swimming

Three Easy Ways to Check for Dehydration, USA Swimming

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