How Dehydration Changes Your Running Performance

How Dehydration Changes Your Running Performance
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Dehydration comes to claim us at one point or another. Whether it is out there on the track running, or weaving through trails against the heat, your body needs hydration to keep moving.

What happens to your body as it loses the life sustaining substance it needs?

What Dehydration Is


Dehydration is your body losing an essential life source. Over two thirds of your body consists of water. With any imbalance in the level of water your body needs, it creates inefficiencies in your blood flow. Inefficiencies in turn inhibit the body's ability to heal, which can cause injury and create fatigue. Your body has a protective mechanism to keep you from being mildly dehydrated, but it forces your kidneys to work harder to maintain optimal functioning.

Your body uses glycogen more when you are dehydrated, which is a form of carbohydrates. Glycogen creates fuel for your body that helps your muscles maintain strength. Without it, your brain will not communicate properly with your muscles. Down the road it can create the confusion symptom of dehydration.

As you sweat during your workout, it creates deficiency in electrolytes, which includes sodium, potassium, magnesium, calcium, and chloride. When your body loses electrolytes, it creates muscle fatigue, and hinders your body from recovering. Lack of hydration can also cause your blood to run thick, which slows down much needed processes to heal after a run. Putting water back into your system encourages proper blood flow, which can in turn help you run longer and heal faster.

Symptoms of Dehydration

The signs of dehydration can often be subtle issues that manifest into a bigger problem. Ranging from subtle dry lips to severe exhaustion, runners have to be careful when running too far out without access to water.

dehydration graphic-1

Symptoms include feeling dizzy or stomach sick, dry mouth, headache, muscle cramps, decreased frequency of urination or concentrated urine that is dark in color and strong in smell, sunken eyes, listlessness, confusion, rapid heartbeat or breathing, shock, and even unconsciousness. If any of the symptoms come to your attention, you should hydrate immediately with water or a sports drink that includes electrolytes.

Consider getting a hydration pack or belt to keep yourself hydrated during runs. If carrying extra weight as you run does not sound appealing, then try to run along a route that has drinking fountains or access to water. Staying hydrated as you run is key in keeping optimal running health.

Runners Beware

Beware of the negative effects of not hydrating yourself enough. As your body moves with the rhythm of your feet, it needs the right energy to keep up stamina. To maintain stamina and increase your mileage, your body needs what it is mostly made of. Your body mostly consists of water, which is the source of life that fuels vital functions to keep you alive. As you run, it forces the systems in your body to work harder to keep itself fueled and hydrated.


Know your body's limits and understand that it is possible to take in too much water. Hyponatremia causes your water level to rise and your sodium level to decrease. From mild to severe cases that have occurred for many marathon runners, choose to be aware of how much water your body actually needs.

Depending on your weight, fitness level, and level of activity, you need differing amounts of water. Eight cups a day is just a general rule, so assess your body as well as the environment you are running in. Heat can extremely effect your need for hydration, so be sure to increase your water intake in higher temperatures or humid days.

Your running performance will be hindered without proper hydration as your body becomes more fatigued after a run. By keeping your muscles well hydrated, it helps you recover faster from quick sprints and long runs. Even losing 5% of water in your body as you run, can decrease your performance by 30%. Beware of the negative effects of dehydration that can extremely hinder your running performance.

The Pure Benefits of Water


Water has a unique ability keep the levels in your body regulated. It regulates digestion, temperature, reduces toxins, lubricates the eyes and joints, as well as helps your body grow by maintaining nutrients. You need water to survive, which is why it is an essential part of being a runner.

Before, During, After

The secret to optimal hydration is to drink before, during, and after. Keeping your body consistently hydrated will help you run longer, faster, and harder. Your muscles need the proper nutrients to build up strength. The only way for nutrients to reach every corner of your body, is to drink water.

Research in the early 20th century claimed to drink little to no water while training, while the later half of the century claimed to drink more water than necessary. Today's research reveals the benefit in monitoring your own body and knowing what you need. Drink when your body needs it, and monitor your intake by assessing how often you have to use the restroom. If you're spending too much or too little time stopping to use the restroom, then you need to reassess and change your hydration habits.


Have a glass of water or two with every meal to help practice good hydration levels. With a balance of water, electrolytes, and nutrients, your body will be feeling healthier than it has before.

Drinking water in general is healthy for you, but it is vital as a runner. If drinking water is too plain for you, consider doing fruit infused water or supplementing with a sports drink that has a high electrolyte count.

Dehydration hinders your running performance, and can increase your fatigue as well as the possibility of being injured. Hydration empowers you to be a healthy runner who can increase their mileage with the right blood flow and nutrients. Run your best by being aware of your water intake. With every sip of water, you will be steps closer to being a healthy runner who achieves your running goals.

Monitor your level of hydration to run at your best every single day.


Bethany Widdicombe

Bethany Widdicombe

Bethany Widdicombe is a runner at heart, a researcher by nature, and a writer by passion. Having traveled across the world, she continues to be an advocate for awareness and knowledge that empowers people to a better life. You can now find her running out on the trail, or nestled away writing her next article.

Portland, OR