Sports Drinks & You: Rehydration

In 2017, CrossFire CrossTraining and Krav Maga posted an article about water and hydration, which briefly mentioned the use of sports drinks. The end of the article states only general advice: if a workout lasts longer than 45 minutes, a sports drink with 6-8% sugar might be a good source of energy and hydration.1 While the general rule holds true, researchers, fitness professionals and sports drink companies have long debated what constitutes a good sports drink and whether sports drinks are, as a whole, useful at all. This article is one of three that will discuss what constitutes a sports drink, what can be used as a sports drink, and the issues surrounding sports drink research.


What is a Sports Drink?

To begin, we should define what the term sports drink is referencing. The label sports drink covers a wide range of beverages, most of which are designed to aid individuals engaging in physical activity more intense than is usual for them. The composition of sports drinks varies, but the drink must contain something other than water, including some kind of carbohydrate, usually in the form of sugar. The debate surrounding sports drinks is generally concerned with how useful these drinks are and what circumstances increase or decrease their usefulness.


Typical Ingredients in Sports Drinks

When exercising, your body loses more than just water. Sweat contains sodium as well as water, so both water and sodium levels must return to a balanced state before rehydration occurs.2 Sodium loses only tend to become noticeable in those who sweat heavily or exercise longer than two hours.3

Sports drinks also tend to include carbohydrates and caffeine. Carbohydrates, usually in the form of sugar, are used to increase the amount of fuel available to your muscles while you work out.4 Caffeine is added to provide quick energy. In tests, however, caffeine was shown to be most effective after 45 minutes of exercise, so it may be more beneficial to drink caffeine before exercising rather than during.5

While most sports drinks include one or more of these ingredients, the amount of each component is what sets sports drinks apart from one another. According to proponents of sports drinks, a sports drink with proper amounts of each component may allow for improved performance during exercise because of the carbohydrate and sodium content.6


Dehydration and Hypernatraemia

Most sports drinks are formulated to reduce the chance of hypernatraemia, which occurs when the body is low on sodium and cannot perform properly. Reports of hypernatraemia, however, are few. The cases that have been reported are often associated with ultra-marathon or triathlon events, not the average workout.7 A test conducted on tennis players found that even individuals who played for six hours a day, with breaks every two hours, did not have problems with carbohydrate or sodium loss. During their breaks between matches, the players were given water-based hydration and balanced meals, negating the need for additional supplements like sports drinks.8

How much water you need to drink in order to feel hydrated is a highly individualized experience.9 While discussions within the sports nutrition community have focused on replacing all the fluid lost during exercise, this advice needs to be balanced against the duration and intensity of sweating. Drinking too much water too quickly can cause further sodium imbalances if an individual is sweating heavily and exercising intensely for hours at a time.10 Research participants have reported feeling discomfort when forcing themselves to drink more water than they were used to, even if they were technically dehydrated.11


Final Notes

The science and research behind sports drinks is complex and the debate surrounding the use of sports drinks is ongoing. For the average consumer of sports drinks, however, the best advice is often to listen to your body. If you drink water, and you find yourself unusually tired for long periods of time after exercise, sports drink or some form of carbohydrate might help.12 If you feel fine drinking water, then sticking with that routine is likely to be fine. It’s often a good idea to keep water on-hand when exercising, in the event you do need it. But you don’t need to force yourself to drink when you feel full, especially when doing so may make you nauseas or otherwise ill.

If you choose to drink sports drinks, remember that the research citing their benefits are often the result of participants who are very active for long periods of time, many of whom sweat profusely. If those guidelines apply to you, then sports drinks might be something to consider. If not, then water may well suit your needs.


If you choose to bring sports drinks to class, please be sure they are tightly sealed when closed. Spilling sugary drinks will attract insects and make the floors sticky. For those who drink water, a water fountain is always available in the MAI dojo. Whatever you choose to bring to class as your hydration, we look forward to seeing you in class soon.



  1. Karen Andes and Diane A. Welland, M.S., R.D., The Complete Book of Fitness: Mind · Body · Spirit (New York: Three Rivers Press, 1999), 248.
  2. S.M. Shirreffs, “Hydration in sports and exercise: water, sports drinks and other drinks,” Nutrition Bulletin 34, no. 4 (2009): 375, doi:10.1111/j.1467-3010.2009.01790.x.
  3. S.M. Shirreffs, “Hydration in sports and exercise: water, sports drinks and other drinks,” 375.
  4. S.M. Shirreffs, “Hydration in sports and exercise: water, sports drinks and other drinks,” 376.
  5. Marc Johnson, “The Effects of Sports Drinks Containing Caffeine and Carbohydrate on Soccer-Specific Skill Performance During Match-Induced Fatigue” (master’s thesis, University of Victoria, 2009), 45,
  6. S.M. Shirreffs, “Hydration in sports and exercise: water, sports drinks and other drinks,” 378.
  7. S.M. Shirreffs, “Hydration in sports and exercise: water, sports drinks and other drinks,” 377.
  8. Thibault Brink-Elfegoun, Sébastien Ratel, Pierre-Marie Leprêtre, et al. “Effects of sports drinks on the maintenance of physical performance during 3 tennis matches: a randomized controlled study,” Journal of the International Society of Sports Nutrition 11, no. 46 (2014): 9,
  9. S.M. Shirrefffs, “Hydration in sports and exercise: water, sports drinks and other drinks,” 376.
  10. Sandra Fowkes Godek PhD, Richard Burkholder, MS and Gary Dorshimer, MD, “Sweat Rates, Sweat Sodium Concentrations, and Sodium Losses in 3 Groups of Professional Football Players,” Journal of Athletic Training 45, no. 4 (August 2010): 369,
  11. Marc Johnson, “The Effects of Sports Drinks Containing Caffeine and Carbohydrate,” 44.
  12. S.M. Shirreffs, “Hydration in sports and exercise: water, sports drinks and other drinks,” 378.

Author: CrossFire Sensei

Share This Post On