Starting exercise hydrated, hydrating during exercise and replacing lost fluids and electrolytes after exercise are important strategies for athletes seeking optimal performance. But why is hydration so important?

Simply put “water is critical for life” as it plays a key role in nutrient transport and solubility, blood volume & blood pressure, body temperature regulation and tissue protection & lubrication. And as athlete, you likely noticed the effects of dehydration on some of these critical functions.

For example, think about a time when you were training in the hot, very humid weather and suffered fatigue, experienced GI distress or felt the effects of the heat. Physiologically, when you body senses a core temperature increase as can occur with exercise and/or in hot and humid conditions, it tries to restore body temperature homeostasis by utilizing available water in the blood to produce sweat. Sweat helps offload heat through a process called evaporative cooling i.e. as the sweat reaches the surface of your skin, it will evaporate resulting in a cooling effect. However, in humid weather, the sweat doesn’t evaporate effectively (or at all) so the body has difficulty cooling itself which in turn results in increased, but ineffective sweating which can dehydrate an athlete even further. Additionally, dehydration can lower fluid levels in the blood resulting in an increased heart rate and less nutrients being delivered to working muscles resulting in fatigue at what might typically be considered an “easy” effort.

So how do you know if you are hydrated? Perhaps you’ve heard about the U.S. dietary reference intake (DRI) guideline that recommends women obtain 2.7L of water (~90 oz.) from food & beverage or 2.2L (~75 oz.) of water per day. However, this level of intake is likely insufficient for female athletes. Thankfully, there are several simple and proven approaches to help evaluate hydration status and inform a solid hydration strategy: evaluating urine color (pale yellow or clear = hydrated), measuring weight before/after key training sessions, utilizing urine test strips (USG) or taking a sweat test. Additionally, there are helpful hydration guidelines developed and published by Dr. Stacy Sims that can be used to help develop a hydration strategy. For more information and to learn more about these guidelines and information on how to select a sports drink, download our Hydration Fact Sheet.

However, each athlete is an individual and has unique hydration needs. Need help developing a personalized hydration plan? Schedule a complimentary 15′ call to learn more.

References

• Thompson and Manore. Nutrition: An Applied Approach. 5th Edition.
• Sims, S. T. (2021). Hydration cheat sheet v.2: hydration for optimal performance. Retrieved from https://www.drstacysims.com
• Sims, S. T. (2021, October 26). Hydration is power harness yours. Hydration is Power Harness Yours. Retrieved from https://www.drstacysims.com/blog/hydration-is-power-harness-yours.
• National Academies of Sciences. (2005). Nutrient Recommendations: Dietary Reference Intakes (DRI) – Dietary References for Water and Electrolytes. Retrieved from https://ods.od.nih.gov/HealthInformation/Dietary_Reference_Intakes.aspx
• Holtzman, B., Ackerman, K.E. Recommendations and Nutritional Considerations for Female Athletes: Health and Performance. Sports Med 51, 43–57 (2021). https://doi.org/10.1007/s40279-021-01508-8
• Paola Rodriguez-Giustiniani, Nidia Rodriguez-Sanchez & Stuart D.R. Galloway (2021) Fluid and electrolyte balance considerations for female athletes, European Journal of Sport Science, DOI: 10.1080/17461391.2021.1939428
• Huang, W.-C., Tung, Y.-T., Wu, M.-S., Liu, M.-C., Lin, T.-J., & Yang, M.-T. (2020). Low-osmolality carbohydrate–electrolyte solution ingestion avoid fluid loss and oxidative stress after exhaustive endurance exercise. Antioxidants, 9(4), 336. https://doi.org/10.3390/antiox9040336