Hydration, electrolytes, and the individualized needs of athletes: Recap from The Outlook on Active Nutrition

Katie Salomone is a registered dietitian specializing in sports dietetics and director of sports nutrition at Rutgers University. At The Outlook on Active Nutrition, she presented “The Hydration Breakdown: What Testing, Data, and Experience Tell Us,” a comprehensive overview of the importance of hydration in athlete health and performance, using data she collected herself on best practices for managing hydration.

Understanding hydration and its importance

Proper hydration is the foundation for optimal performance, impacting all other efforts for nutrition and training habits, Salomone states. “Optimal hydration is going to allow you to maintain your endurance, your speed, your power, your overall performance, support recovery, your immune system, general health, and minimize the risk of injury,” Salomone explains. To illustrate the risk of injury, she gives the example of jerky and raw chicken breast – the jerky is easier to tear while the hydrated chicken breast is not.

Impact of hydration on performance

A 1% loss in body weight can impact an athlete’s physical performance, and a 2% loss starts to affect cognitive and aerobic performance, Salomone explains. Environment, exposure to various temperatures, and travel also impact the need for water and electrolytes. For example, she pointed out that the cabin of an airplane is less humid than the Sahara Desert. During actual game play, basketball players, for example, may play 30 minutes during a two-hour game, including free throws, and their hydration and performance at the beginning and end need to be optimal.

Individualizing hydration plans and supplements

Salomone recommends athletes have five to 10 milliliters per body weight of hydration before activity or practice, based on recommendations from the American College of Sports Medicine and the Academy of Nutrition Dietetics, which is paired with the dietitians of Canada and the American College of Sports Medicine. However, not every athlete is able accomplish this. A runner training at 7am is not expected to wake up two to four hours prior to start hydrating, while athletes training at 1pm can start their hydration the same day. This means they have to hydrate the night before and top themselves off in the morning.

During activity, Salomone states that she does not want athletes to lose more than 2% of their body weight. This too requires individualized plans. After activity, athletes require between 16 and 24 ounces of fluid for each pound they lost. Salomone states that she typically has her athletes drink 20 ounces, so if an athlete lost two pounds during practice or play, that means they need to drink 40 ounces of fluid.

When it comes to electrolytes, Salomone states that the electrolytes that are primarily lost in sweat are sodium and chloride, and therefore the ones she pays the closest attention to. However, athletes also lose potassium, magnesium, and calcium that need to be replenished.

“So, sodium, chloride, potassium, they work together to help regulate and maintain fluid balance, while your magnesium and calcium are going to be more so play an optimal role in your muscle function, heart,…energy metabolism,” she explained.

Gathering and analyzing data

To start developing an individualized plan, Salomone meets with athletes individually to analyze their current hydration habits, supplements, nutrition, and history of cramping. She gathers data on weight, using an example of basketball players before and after practice – the weight lost varied from 2.8% of a player’s body weight to other players showing overhydration. That 2.8% amounts to six pounds, requiring them to drink 112 ounces to regain that loss ahead of their next practice, on top of the five to 10 mL per body weight of hydration for optimal function.

Once per year at minimum, Salomone conducts sweat tests on the athletes in order to assess their hydration needs. Each athlete wears a patch for an hour, after which sodium chloride is assessed as well as the amount of fluid lost, identifying which athletes she needs to ensure have proper hydration. She highlighted the example of one athlete that lost 3000 mg of sodium in one hour, while another athlete lost only 684 mg, highlighting just how variable their needs are. This then informs to type of product the athlete will need, as levels of electrolytes vary from product to product.

Sampling and individualizing hydration supplements

After gathering the data, the next step is sampling products to identify which ones the athletes prefer. “The main thing that I look for in hydration supplements is going to be a variety,” Salomone explains. “I need different flavors to accommodate the athletes’ preferences. I need different sodium amounts. I look for carbs. Carbs improve palatability. If the athlete won't drink it, there is no point in me giving it to them.” She also considers the osmolality of the product, especially in relation to an athlete with gastrointestinal issues, IBS, or Chrohn’s disease, when a product could upset their stomach and cause additional issues.

A more detailed hydration plan, for example, identifies training days based on intensity levels and anticipated sodium loss, and adjusts the types of supplements that will be needed, from Gatorade to Liquid IV to Element and others.

Key takeaways and athlete empowerment

Salomone reiterated the importance of proper hydration, limiting body mass loss to less than 2% body weight support athletes’ physical and cognitive function, and replenishing sodium and chloride, the main electrolytes lost in sweat. A variety of supplements is also important to accommodate various flavor profiles and help athletes adhere to their hydration plans. The plans should be individualized and reassessed to support trainings and environments, she adds. Also significant is ensuring that athletes feel involved in their hydration plans and empowered to make decisions within them.

This article was created with assistance from Gemini. The content has been reviewed and edited by Erin McEvoy, Associate Editor. For more information on the extent and nature of AI usage, please contact us.