Hydration For Runners: How To Hydrate Before, During + After A Run

Hydration is a crucial aspect of running that should never be neglected.

Most runners understand that hydration is important, but understanding how to hydrate properly before, during, and after a run requires research and a bunch of practice.

Staying properly hydrated can make or break your performance, whether it be a race or a training session. To help you run at your best, we decided to take a deep dive into the how-tos of hydration for runners. 

In this article, we talk about hydration for runners and discuss the details of how to hydrate before a run, while running, and after your run. 

We will get into the following:

  • Importance of Hydration for Runners
  • How to Hydrate Before Your Run
  • How to Hydrate During Your Run
  • How to Hydrate After Your Run
A runner holding a bottle of water smiling at the camera.

Importance of Hydration for Runners

Staying hydrated as a runner is important for many reasons. It can positively impact your performance, help regulate your body temperature, and encourage proper energy and muscle function. 

While many people think of hydration as just taking in fluids, it is important to know that you must also consume electrolytes so that your body can properly absorb the fluids that you are consuming. 

Research shows that it is important to focus on proper intake before, during, and after you exercise to avoid losing too much body weight (primarily water weight) between exercise sessions. 

Ideally, you should take in at least as much fluid as you are sweating out, but avoid taking in excess fluid, as overhydrating can cause hyponatremia. This severe electrolyte imbalance can result in a medical emergency. 

At the end of a hard long run or other workouts, your body weight should not have reduced by greater than 2%.

A runner drinking water.

It has also been suggested that if you are going to be working out for more than an hour, you should add carbohydrates and electrolytes to your fluids. This would mean drinking a sports drink or adding some type of electrolyte powder or concentrate to your water.

This is because, in sessions over one hour, you will most likely sweat in greater quantities, which means losing electrolytes and fluids and utilizing a lot of calories. 

If you fail to stay properly hydrated, you may experience muscle cramping, GI distress, headaches, joint aches, and other physical discomfort.

If you become severely dehydrated, you could experience more severe symptoms and develop conditions like heat stroke or hypernatremia.

How to Hydrate Before A Run

Hydrating before your run should be as important to you as hydrating during your run. This is especially true if you plan to participate in an event that is long or takes place in very hot or humid conditions or at elevation. 

A runner drinking water.

Proper Pre-Run Hydration For Runners

In order to make sure you are ready for whatever event or run you are planning to do, you should set pre-run hydration goals.

Some people’s bodies rely on proper hydration to perform adequately more than others. This is why it is so important that you know how to hydrate before a run.

As a competitive athlete, I have worked with an endurance sports dietician to determine my hydration needs. This was helpful because having a good understanding of your body’s specific needs can help you to avoid discomfort during runs.

This can be especially true for people with gastrointestinal issues or muscle cramping problems. 

Reaching out to a professional to help you better understand hydration for runners is a great idea if you have big events in the future.

Generally, if you run longer than 90 minutes, you should drink at least 16-20 ounces of fluids within an hour or two before. If you have a run or race over 2.5 hours, you should aim to consume at least half your body weight in fluids the two days before the event. 

A runner drinking a sports drink.

Electrolyte-Rich Beverages 

Intaking electrolytes with your fluids is crucial as it helps your body to actually hold onto the water you are taking in. You can add things like NUUN tablets, Tailwind, LMNT, or Skratch Hydration powder to your water; these are all great when it comes to hydration for runners.

There are various electrolyte options, some have calories while others do not, and many flavors and brands exist. If you have a sensitive stomach, you should explore the different options to find something that will hydrate you and sit well once you start running. 

Avoid Excessive Caffeine and Alcohol Intake

Some people may be more sensitive to these substances than others, but both caffeine and alcohol have some diuretic effects.

Diuretics tend to make you have to urinate more often, which encourages fluid to leave the body, which is not ideal since you want your body to be hydrated and ready to go. 

Prior to a long run or race, you should limit your intake of beverages loaded with caffeine as well as alcohol so that you are better able to hold onto the fluids you take in. 

A person handing a cup of water to a runner during a race.

How to Hydrate During A Run

The more experienced you become with running, the better your understanding of hydration for runners will be. With time, you will get to know your body’s needs, and your hydration routine will become more efficient.

Hydration routines during runs and races can change over time as you learn more about your body and throughout the seasons due to weather changes. 

Understand Fluid Needs During Exercise

How much fluid you need during your run depends on various factors. Each individual has their own sweat rate. Testing your sweat rate as you amp up for the high-volume running season is a good idea to ensure adequate hydration during your runs and races. 

To determine your sweat rate, you must calculate how much fluid you lose during exercise. This is calculated by tracking the amount of fluid you take in before your workout and your body weight before your workout. 

A runner drinking water.

If you urinate or eat before or during your workout, this should also be tracked, as you want to know the exact weight of what is going in and out of your body. 

Things like the weather, elevation, humidity, the type of exercise you are doing, how intense your workout is, and your clothes can impact your sweat rate.

For more accuracy, repeat this assessment a few times a year. There are multiple sweat rate calculators available online to assist you. 

Knowing how much fluid you lose during activity will help you to determine how much fluid you need to take in during activity without over or underdoing it. 

Some people are heavy and salty sweaters, while others do not sweat much, and when they do, they do not lose a lot of salt.

If you notice salt on your skin post-run, this is a good indicator that you should take a good amount of electrolytes during your runs. Some running gels include electrolytes as well. 

You should refer to your electrolyte product of choice for dosing suggestions. As a general rule of thumb, taking in 16 to 20 ounces of water every hour you run is a good idea. 

A runner holding a water bottle.

Carry Water and Plan Stops 

If you plan to run for more than 90 minutes or will be running on a very hot or humid day, you should carry water with you. There are a variety of hydration packs, vests, hand bottles, and belts that you can purchase that allow you to carry water with you while you run. 

If you do not have a way to carry water while you run or do not want to, you should be sure to run a route with access to water along the way. Some parks with running paths have drinking fountains or fill-up stations along the route. 

If you are a trail runner, you should always keep water with you if you are going more than a few miles from the trailhead, as you are less likely to have access to water. It is also a good idea to carry a filtering straw or bottle for extra-long outdoor adventures. 

Remember to listen to thirst cues and drink even if you are not thirsty. A great tip is to take a sip at least every 20 minutes, even if you do not feel thirsty. 

How to Hydrate After A Run

Replenishing the fluids and electrolytes you lose during your run is important because being properly hydrated post-run helps you to recover more quickly so you can be ready for your next one. 

Failing to rehydrate may cause headaches, nausea, and an upset stomach. If you feel off after a run and cannot seem to bounce back, check in with yourself on hydration. If your urine is dark in color, this is a sure sign that you need to rehydrate. 

A runner drinking water.

How to Replenish Fluids and Electrolytes Post-Run

Immediately after finishing a run, you should start drinking fluids. While this may be a given when you run on a hot day, many people who run on cooler days neglect their hydration needs without realizing it. 

While drinking straight water is okay, you should also aim to drink sports drinks or other fluids with electrolytes to replenish your sodium levels.

Consuming a well-balanced post-run snack or meal can also help to replenish electrolytes and nutrients lost during your run. 


Understanding hydration for runners and staying properly hydrated is not always easy, but it is always worth it. The effects of being over or under-hydrated can be detrimental to your performance, recovery, and overall health. 

By starting your run hydrated, properly hydrating during your run, and being sure to replenish what you lose, you are more likely to avoid things like feeling sick and weak and the need for extended recovery time after a hard or long effort. 

If you don’t have any electrolytes on hand but want to start properly hydrating today, give one of these 5 Fast + Easy Homemade Electrolyte Drink Recipes a try!

A runner drinking water on the beach.
Photo of author
I am a UESCA-certified running coach, psychology PhD student, and competitive obstacle racer and trail runner. Once 100 pounds overweight I found fitness and fell in love with an active and competitive lifestyle. My passion for inspiring others and fitness come together seamlessly in the world of writing where I get to share the thing that changed my life. In my free time I enjoy spending time with my family, my dogs, as well as baking and cooking.

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