Ultimate Guide to Hydration for Runners
Updated: Jan 26
How to perfect what, when, and how much you should drink to optimize your performance.
It goes without saying that proper hydration results in a better chance of achieving your goals for training and racing. But how exactly do you hydrate? Are eight glasses a day of water enough for athletes? Do you need sports drinks or is plain water enough? When exactly do you need to drink your fluids?
There are a lot of factors to consider in proper hydration from sweat and pee to electrolytes and food to the heat and humidity outside.
Our team of West Coast Road Runners Coaches have poured over the research and have consumed a lot of liquids during training and racing to be able to provide you with the best possible information about how to calibrate your hydration routine to optimize your performance.
Why Should Runners Focus on Fluids?
Did you know that more than half of your body weight is water? In fact, that number jumps up even higher for endurance athletes to about 60% of your body being water . During daily activities including exercise, your body loses fluid through sweating and breathing. Research has shown that if athletes lose as little as 2% of their total body weight during a workout or a race, their performance can deteriorate . Why would this water weight-loss (dehydration) negatively impact performance? Dehydration reduces the amount of blood circulating in your bloodstream which can result in :
Your blood becoming more viscous (thicker and more concentrated)
Your heart working harder
Your body having difficulty cooling itself
Premature muscle fatigue
What Should You Consume to Stay Hydrated?
How Hydrated Are You?
Feeling thirsty can help us know when we should take a drink during daily life, but the feeling of thirst is of questionable sensitivity in determining if you are adequately hydrated during exercise [2, 4]. Marathon runners face a complicated set of dynamic factors in maintaining a sufficient level of hydration. For example, your own personal sweat rate, how intensely you are running, how long you are running, the temperature, humidity, and amount of wind will all impact your level of hydration when you are exercising outdoors.
So, how can you tell if you are hydrated enough? Try one of these two methods:
Check your urine color (yes, I said to look at your pee). If your urine is dark gold, you are likely dehydrated, but if the color is similar to pale lemonade you are likely hydrated . Review the urine color chart for examples of these colors.
Weigh yourself before and after you run to see how much weight you have lost due to sweating. Then replace each pound you have lost with about 16 ounces (2 cups) of fluid.
Note that if you are monitoring your fluid loss during exercise by weighing yourself, you should be weighing yourself naked before and after the run (you don't want to be including how much your sweat-soaked clothes weigh), and complete your run without replacing your fluids to see how much you sweat. Remember that the dynamic factors of weather and how long and intensely you are running can impact your personal sweat rate. Additional factors to consider that might also affect your hydration include medications you are taking, your menstrual cycle, and your diet .
What Should You Consume to Stay Hydrated?
Ideally, you want to select fluids for yourself that taste good and are palatable (so that you want to drink them and enjoy hydrating with them). You also want to make sure what you are consuming doesn't upset your stomach when you are out on a long training run or racing. Finally, consider hydrating with fluids that can be readily absorbed and that will also provide energy to your muscles during endurance training.
Water (yep, good old tap water) should be a key player in your hydration routine.
You can flavor water with lemon, lime, berries, or other fruits if you prefer to have a "taste" when you drink. Decaffeinated teas and broth-based soups are also good options for hydration throughout your day. In contrast, avoid or minimize beverages that contain caffeine or alcohol. Also avoid or minimize carbonated drinks, as they can upset your stomach or may lead you to consume less fluid because they make you feel "full."
For long runs (60 minutes or more) or intense training sessions, consume beverages with electrolytes . Consuming electrolytes will help improve your muscle function and help prevent cramping. Sodium is a mineral that is lost in sweat and urine, so replacing it is key for optimizing hydration. Potassium is another electrolyte that balances the effects of sodium and is important in hydration . High quality electrolyte drink mixes are available from nutrition companies like Vitalyte and UCAN.
Remember to consider foods in your hydration routine.
When most of us think of hydration, we focus on what we are drinking. However, up to 20% of your daily water intake usually comes from foods and there are many healthful hydrating foods that you can consume to optimize your hydration [6, 7]. Below are several foods that contain at least 85% water (and many great vitamins too):
When & How Much Should You Hydrate?
Optimal hydration will occur if your routine includes hydrating before, during, and after your workout. You want to avoid drinking too much right before you run (nothing feels worse than water sloshing around your tummy when you run), but you should try to drink about 8-12 ounces of fluid about 30-60 minutes before your workout [1, 8].
During your run, try to drink small amounts every mile or two (or every 20 minutes or so). Many athletes find that gulping down large amounts of fluid all at once is a less effective hydration strategy and drinking smaller amounts (a few sips to about 4-ounces) is more effective and easier on the stomach. Remember to drink early in your workout, so that dehydration doesn't begin to impact your performance.
After your training run or race, rehydrate well to optimize your recovery. Post-run, try to consume 16-24 ounces of fluid . Keep in mind, that after your run, your rehydration continues throughout the day and may also include things like soup and water-laden fruits and vegetables.
Practice makes perfect when it comes to hydration for runners.
No matter what your individualized hydration plan is, it is important to practice hydrating during your training. Sometimes, the only way to figure out what is going to work for your gut is through trial and error. Don't wait until race day to determine what type of electrolyte drinks work best for you or to learn how frequently and how much you need to consume to stay adequately hydrated. To have your best possible performance, create your individualized hydration plan, practice it, and then fine tune-it for race day!
US Anti-Doping Agency (2021). Nutrition Guide: Fueling for Performance.US Anti-Doping Agency (USADA). www.usada.org/athletes/substances/nutrition/fluids-and-hydration
Belval, L. N., Hosokawa, Y., Casa, D. J., et al (2019). Practical Hydration Solutions for Sports. Nutrients, 11(7), 1550. doi.org/10.3390/nu11071550
Mohr, C. (2019, July 12). Five hydration myths that could hurt your health. Runner's World. www.runnersworld.com/uk/nutrition/hydration/a28375289/how-to-stay-hydrated
Hew-Butler, T., Verbalis, J. G., & Noakes, T. D. (2006). Updated fluid recommendation: Position statement from the international marathon medical directors association (IMMDA). Clinical Journal of Sport Medicine, 16(4), 283-292. doi.org/10.1097/00042752-200607000-00001
Ayotte, D., & Corcoran, M. P. (2018). Individualized hydration plans improve performance outcomes for collegiate athletes engaging in in-season training. Journal of the International Society of Sports Nutrition, 15(1). https://doi.org/10.1186/s12970-018-0230-2
Brennan, D. (2020, November 3). Foods high in water. WebMD. https://www.webmd.com/diet/foods-high-in-water
Berry, J. (2019, August 7). The top 20 most hydrating foods. Medical News Today. https://www.medicalnewstoday.com/articles/325958
Kadey, M. (2021, May 26). When it is time to rethink your hydration. Runner's World. www.runnersworld.com/nutrition-weight-loss/a36186815/when-its-time-to-rethink-your-hydration