Athletes often undervalue the impact of water and hydration, yet they are essential for athletic success.  Staying properly hydrated aids in regulating body temperature, transporting nutrients, and removing waste from the body thereby improving performance and recovery time and reducing injury [1].  Determining how much fluid an athlete needs can be a big tricky; however, there are many ways of doing so.  As always, we encourage you to consult with your doctor or a registered dietitian to best assess your individual requirements.  

Before we explain how to calculate hydration needs for this particular population, it is important to understand the implications of being under or overhydrated.  Dehydration can lead to a decrease in blood volume, which in turn can reduce the amount of oxygen and nutrients reaching the muscles.  Additionally, it can lead to muscle cramps, heat exhaustion/heat stroke [1], and as a result, decreased exercise capacity.  On the other hand, overhydration can be just as dangerous.  Hyponatremia, or low blood sodium, can occur when a person consumes too much fluid without adequate sodium [2].  This can cause symptoms such as nausea, vomiting, confusion and seizures [2], all of which can have serious consequences for an athlete’s health and performance. 

The amount of fluid each athlete needs to consume is dependent on several factors such as the intensity and duration of their workout, the climate they are exercising in, their individual sweat rate, and their body weight [1,3]. 

As athletes exert more energy during longer and higher intensity training sessions, they tend to sweat more.  This loss of fluids can lead to dehydration if not appropriately replenished.  Sweating also functions as a means of regulating body temperature.  In hot and humid conditions, athletes sweat more to cool themselves down [4], therefore, increasing fluid loss and the need to drink more to stay properly hydrated. 

A more precise method for determining fluid requirements is to look at an individual’s sweat rate, which can vary greatly from person to person.  One way to determine this metric is by weighing yourself before and after a workout.  While we don’t always like to put emphasis on the scale, it can be a helpful tool in estimating how much fluid you lose through activity and how much to replete.  Generally, athletes should aim to consume 16-24 oz of fluid for every pound of body weight lost during exercise to adequately rehydrate1.

A potentially simpler way to calculate fluid needs is to take your body weight and divide it in half.  This will give you the approximate amount of fluid ounces you need to drink on a daily basis [4,5].  However, if you are extremely active or sweat a lot, you may need to consume more fluids to replenish what you’ve lost. 

In conclusion, hydration should always be a priority for those wanting to excel in their sport.  It is important for athletes to listen to their bodies and pay attention to signs of dehydration such as increased thirst, dark urine, dry mouth, and fatigue [6].  Alternatively, your doctor or registered dietitian can help you develop a plan to ensure optimal hydration levels.  By staying properly hydrated and replenishing lost fluids, athletes can support their performance, prevent dehydration, and maintain overall health. 

References

1. Eby S. Hydration Tips for Athletes. www.massgeneralbrigham.org. Published June 5, 2023. Accessed July 16, 2024. https://www.massgeneralbrigham.org/en/about/newsroom/articles/tips-for-staying-hydrated#:~:text=
2. Radcliffe S. Overhydration: Types, Symptoms, and Treatments. Healthline. Published March 25, 2014. Accessed July 16, 2024. https://www.healthline.com/health/overhydration#_noHeaderPrefixedContent
3. Judge LW, Bellar DM, Popp JK, et al. Hydration to Maximize Performance and Recovery: Knowledge, Attitudes, and Behaviors among Collegiate Track and Field Throwers. Journal of Human Kinetics. 2021;79(1):111-122. doi:https://doi.org/10.2478/hukin-2021-0065
4. The Hydration Equation in Athletic Performance. Direct Orthopedic Care. Published August 25, 2020. Accessed July 16, 2024. https://www.directorthocare.com/the-hydration-equation-in-athletic-performance/
5. Kumar K. How Much Water Should You Drink Based on Your Weight? MedicineNet. Published February 1, 2023. Accessed July 16, 2024. https://www.medicinenet.com/how_much_water_to_drink_based_on_your_weight/article.htm
6. NHS. Dehydration. NHS. Published August 9, 2022. Accessed July 16, 2024. https://www.nhs.uk/conditions/dehydration/