Hydration and Running – How to Stay Hydrated Before, During, and After Your Runs

August 2nd, 2011

Tips for Drinking to Avoid Heat-Related Illnesses When Running

Staying hydrated is critical to your running performance and, more importantly, for preventing heat-related illnesses. Dehydration in athletes may lead to fatigue, headaches, decreased coordination, and muscle cramping. Other heat-related illnesses, such as heat exhaustion and heatstroke, have even more serious consequences. Runners need to pay attention to what and how much they’re drinking before, during and after exercise.

Pre-Run Hydration
If you’re doing a long run or race (more than 8 to 10 miles), it’s important to make sure you’re well-hydrated during the few days leading up to your long run. You know you’re well-hydrated if you void large volumes of pale urine at least six times a day. In the days leading up to your long run (or race), drink plenty of water and nonalcoholic fluids. Not only does alcohol dehydrate you, but it can also prevent you from getting a good night’s sleep. It’s not a good idea to run with a hangover because you’ll most likely be dehydrated when you start running.
An hour before you start your run, try to drink about 16 ounces of water or other non-caffeinated fluid. Stop drinking at that point, so that you can void extra fluids and prevent having to stop to go to the bathroom during your run. To make sure you’re hydrated before you start running, you can drink another 4 to 8 ounces right before you start.

Drinking on the Run
The current advice about running and hydration is very simple — try to drink to thirst. Scientific evidence says that drinking when you’re thirsty can help prevent underhydrating (which can lead to dehydration) and overhydrating, which can lead to hyponatremia (low blood salt level due to abnormal fluid retention).
If you’re looking for a general rule of thumb for fluid consumption during your runs: You should take in 4 to 6 ounces of fluid every 20 minutes during your runs. Runners running faster than 8-minute miles should drink 6 to 8 ounces every 20 minutes. During longer workouts (90 minutes or more), some of your fluid intake should include a sports drink (like Gatorade) to replace lost sodium and other minerals (electrolytes). The carbohydrates and electrolytes in the sports drink also help you absorb the fluids faster.
If you don’t have access to water on your running routes, you’ll have to carry your own fluids with you. Here are some fluid carriers that you can use to hold your fluids while you run. However, if you’re running in a race, you shouldn’t have to carry your own fluids because they should have water stops on the course.

Post-Run Hydration
Don’t forget to rehydrate with water or a sports drink after your run. You should drink 20 to 24 fl oz. of water for every pound lost. If your urine is dark yellow after your run, you need to keep rehydrating. It should be a light lemonade color.

Source: Maharam, Lewis, MD, et al. “IMMDA’s Revised Fluid Recommendations for Runners and Walkers” 5/6/2006