Menu Close

Drink Up: Why Athletes MUST Stay Hydrated

Drink Up: Why Athletes MUST Stay Hydrated

Why Is Hydration So Important?

Staying hydrated and proper fluid choices are just as important to the athlete’s diet as food. Dehydration can impair function, negatively affect performances and in severe cases, lead to a dangerous increase in body core temperature which can result in exertional heat illness. Loss of as little as 1% to 2% of body weight can begin to compromise an athlete’s physical function.  Exercise-induced sweating results in the loss of fluid as well as electrolytes.  Some athletes are better at taking in fluids than others, and some have a higher sweat rate so varying amounts of fluids can be lost. Many other factors can influence how an athlete loses fluids including outdoor temperature and humidity, exercise intensity and duration, availability of beverages and personal preferences.

Athletes must be aware of how to assess fluid losses, choose the right rehydration beverages and make conscious efforts to balance fluid intake before, during and after activity.

Types of Exertional Heat Illness

Heat Cramps: Painful muscular cramps or tetany following prolonged exercise in the heat without water or salt replacement.

Heat Exhaustion: Weakness or dizziness from overexertion in a hot environment.

Heat Stroke: Elevated body temperature of 105.8F or greater caused by exposure to excessive heat gains or production and diminished heat loss.

When and How Much

Signs and symptoms of mild to moderate dehydration can include thirst, irritability, headache, weakness, cramping, and decreased performance. More severe cases may also present with dizziness, chills, nausea, vomiting, and loss of consciousness. In severe cases, intravenous rehydration may be needed, but milder cases can be remedied orally.

Ideally, athletes will drink the proper amounts of fluids before, during and after exercise to avoid dehydration altogether. Organizations like The National Athletic Training Association and American College of Sports Medicine have established specific guidelines for fluid replacement, summarized below.  For more details about either, both can be found online.

It is also helpful for athletes to pay close attention to how much they sweat to help them know how much to replenish during and after workouts. It is also valuable for athletes to be weighed before and after activity to account for fluid loss by the change in body weight.


It is recommended that athletes consume 500 to 600 milliliters (17 to 20 fluid-ounces) of water or sports drink 2 to 3 hours before exercise as well as 200 to 300 ml (7 to 10 fl oz) 10 to 20 minutes before exercise begins.

To best facilitate this fluid intake, athletes should work with team members, coaches, and athletic training staff to make sure that the proper fluids are available and accessible.


A general recommendation during activity is 200 to 300 ml (7 to 10 fl oz) every 10 to 20 minutes, but athletes should pay attention to how much they are sweating and adjust accordingly.  Fluid intake during exercise may be more difficult for some sports, especially during competitions or in certain workout situations (such as a long-distance run).


The Academy of Nutrition and Dietetics recommends rehydrating with 450 to 675 ml (16 to 24 fl oz) of fluid for every pound lost during exercise.  Athletes should attempt to replace fluids lost during activity within two hours post-exercise.

The Time and Place for Sports Drinks

Sports drinks can provide much-needed fluids, electrolytes, and energy-producing carbohydrates. Whether an athlete does not have time to eat a pre-workout snack or some additional energy was required during a long workout, sports drinks deliver easily digestible calories that can be quickly absorbed, while also contributing to fluid intake. The flavor that these drinks provide is also well accepted and may get athletes to drink more.

There are many reasons to choose sports drinks over other beverages for fluid, electrolyte and carbohydrate replacement. Properly formulated sports drinks are designed to be digested and absorbed as efficiently as water.  Choose drinks that have a 6% carbohydrate solution. If the concentration of carbs is greater than 8%, the rate of fluid absorption will be slowed. At 6%, gastric emptying and intestinal absorption will not be affected.

How do you determine this value?  Look at the label to determine the serving size of the product and divide that number by the total number of carbohydrate in the entire product.

For example, if there are 355 mL in a product that contains 53 grams of carbohydrate, divide 355 by 53, and you get 6.6%. 

Tips For Staying Hydrated

Athletes can best monitor their hydration status when they pay close attention to how much they sweat. The more fluid lost during an activity, the more needs to be replaced during and following.

One of the best ways that athletes can assess if they are dehydrated is to monitor the color of their urine. If it is typically clear to light yellow, they are hydrating adequately. If it is trending towards dark yellow, they are not getting enough fluids.

The chart on the following page can be used to help determine hydration status.  Many gyms, training centers, college weight rooms, and professional locker rooms have this chart posted throughout as a reminder to the athletes.

Instruct athletes to follow these tips:

  • Drink fluids throughout the day and with meals
  • Follow established guidelines for fluid replacement for before, during and after activity
  • Monitor sweat rate
  • Monitor urine color
  • Eat fruits and vegetables; they also have a high water content

The NESTA Sports Nutrition Specialist course is designed for personal fitness trainers, strength coaches and nutrition experts who want to learn cutting-edge techniques for increasing sports performance, reducing recovery time, and enhancing the overall well-being of your clients and athletes.

Learn more about becoming a Sports Nutrition Specialist by clicking the link below!

>>> https://www.nestacertified.com/sports-nutrition-training-course/

Learn more about nutrition and nutrition for athletes in the Fitness Nutrition Coach program and the Sports Nutrition Specialist program.