Hydration and its Effects on Exercise & Athletic Performance (3)- How Much Fluid Do We Need When Exercising?

During this three part series on hydration, exercise and athletic performance we have covered how dehydration can compromise many aspects of our workouts (Part 1) and what happens to our body when we are dehydrated (Part 2).  What’s next? In this third and last part, we will explore how to determine the proper amounts of fluid based on bio-individuality – the personalization of recommendations otherwise known as precision health*.  We will also cover the different types of hydration and how you can determine the best strategy for you! 

The risks of dehydration and potential consequences to our performance when we are exercising or engaging in athletic activity can be unique from person to person. In a study by Casa et al. in 2019, it was said these differences are due to variable fluid needs from person to person, the diverse nature of exercise, level of intensity of programs, and individual differences among persons engaging in exercise (i.e. how “in shape” a person is). Sweating rates can also evidently range due to differences in factors such as body size, exercise intensity, exercise duration, environment, and choice of clothing.  Nonetheless, it is well-known that a lot of people walk around dehydrated, so first and foremost it is important to make sure you’re drinking enough even before you think about exercising.  When you feel comfortable with your hydration needs and are staying on top of it, then moving on to what you need during exercise and after is key to getting the most out of your workouts. 

The National Athletic Trainers’ Association (NATA) recommends the following practices regarding fluid replacement for athletic participation: “athletes should begin a training session well hydrated by drinking approximately 500 to 600 ml (17-20 oz) of water or sports drink 2 to 3 hours before exercise and additional 200 to 300 ml (7-10 oz) of water or a sports drink 10 to 20 min before exercise. During the training session, fluid replacement should approximate sweat and urine losses and maintain hydration at a level that keeps body weight loss to <2%.” The NATA goes on to state that this can generally be achieved by the consumption of 200 to 300 ml of fluid every 10 to 20 min. 

After your workout or athletic training event, post-hydration should aim to correct any fluid loss that was accumulated. Water quality and mineral content are also factors to consider for fluid replacement as water rich in minerals has been shown to potentially offer advantages in hydration post-exercise (Chycki et al., 2017).  Tap water typically varies all over the world but does contain some minerals.  It also contains things that are not good for health such as PFAS, halogen metals, pharmaceuticals and other toxins.  Using a filter can help ease this burden.  

Recent studies have shown beneficial effects of hydrogen-enriched water in exercise performance. A study performed in male cyclists demonstrated maintaining peak power output during consecutive sprints.  Another one, focusing on conducted study in professional soccer players showed significantly faster sprint times after hydrogen-enriched water consumption compared with placebo.  A third study in “healthy humans” was conducted where participants consumed hydrogen-enriched water for two weeks. The authors of this study concluded, “the continuous supplementation of hydrogen water (HW) potentially augments the aerobic capacity, implying that continuous supplementation of H2 might help improve aerobic exercise performance and physical health.” Lastly, a pilot study in elite athletes showed reduction of blood lactate levels and improved exercise-induced decline of muscle function.  According to these studies, electrolyzed water may be the best choice for hydration – pre- and post-workout. 

Although the NATA recommends water or sports drinks for fluid replacement, sports drinks can contain artificial colors and calories that are above and beyond what a non-athlete needs for replacement needs.  They may better be suited to endurance athletes to replace carbs, fluids and electrolytes after prolonged exercise. Also, energy drinks can be a source of sugar, and while some may be touted as aids for weight loss, they may actually lead to weight gain, according to a 2013 article published in Today’s Dietitian.  

Although there are many choices for hydration needs, keep in mind the most important aspect to consider is that we are indeed, hydrated enough to engage in exercise or athletic activity.  That comes first so we don’t end up hurting ourselves and/or stressing our cardiovascular and musculoskeletal systems.  Secondly, using the NATA as a guide, one may be able to determine what is recommended specifically for them.  You can modify their professional advice as per your own workout.  Also, consider upping your game by bringing in electrolyzed water to be on your team!  The studies are demonstrating a great impact on exercise and athletic performance. 


*What is precision health? 

Precision medicine is an emerging approach for disease treatment and prevention that takes into account individual variability in genes, environment, and lifestyle for each person. This approach will allow doctors and researchers to predict more accurately which treatment and prevention strategies for a particular disease will work in which groups of people as opposed to a one-size-fits-all approach, in which disease treatment and prevention strategies are developed for the average person, with less consideration for the differences between individuals.

Although the term “precision medicine” is relatively new, the concept has been a part of healthcare for many years. Researchers hope that this approach will expand to many areas of health and healthcare in coming years. When it comes to fluid intake and exercise, see this approach as a way to help athletes understand and manage their individual hydration needs.


By Kelly Halderman,  Weo’s Chief Health Officer.



  1. https://theheartfoundation.org/2019/03/08/the-importance-of-water/#:~:text=Dehydration%20can%20negatively%20affect%20your,rate%20and%20your%20blood%20pressure.
  2. Casa et. al. Fluid Needs for Training, Competition, and Recovery in Track-and-Field Athletes VL  – 29 International Journal of Sport Nutrition and Exercise Metabolism
  3. Chycki J, Zając T, Maszczyk A, Kurylas A. The effect of mineral-based alkaline water on hydration status and the metabolic response to short-term anaerobic exercise. Biol Sport. 2017 Sep;34(3):255-261. doi: 10.5114/biolsport.2017.66003. Epub 2017 Feb 19. PMID: 29158619; PMCID: PMC5676322.
  4. https://www.nata.org/sites/default/files/FluidReplacementsForAthletes.pdf
  5. https://www.todaysdietitian.com/newarchives/100713p62.shtml



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