Signs of Dehydration in Runners


What it Means to be Properly Hydrated

The body is made up of approximately 60% water! Water helps with all kinds of functions throughout the body – but when we are talking about running specifically water in the body helps us regulate our temperature, keeps our brain functioning well, helps deliver oxygen throughout the body, keeps our muscles firing properly, and so much more! 

Know before you go!

Make sure you’re properly hydrated before you head out on a run. How, you ask? The easiest way to check hydration levels is to take a peek at your urine!

Hydrate Early

Hydration starts the day before. So if you have a long run, race, or a particularly hot day coming up, start hydrating early to ensure your body is ready to go. If you don’t drink water the day before, night before, and morning of – you won’t be properly hydrated for your run.

Dehydration can have lasting effects throughout the day and even the week. So don’t set yourself back simply because you forgot to sip on water.

Signs of Dehydration in Runners

There are many different signs of dehydration, the following are a few you may start to recognize while out on your run. It is important to know and understand these signs as some could indicate severe dehydration that requires immediate action. Remember that dehydration leads to heat cramps and heat stroke, so get on top of it before it gets worse! 

Some of these signs overlap with the signs of heat cramps and even heat stroke, so depending on the severity it could mean more than just dehydration. Take these signs seriously and do what you need to to get properly hydrated again.

  • Thirst – you should never feel like you need to chug water to be satiated. If you’ve hit this point you are already showing signs of dehydration.
  • Dry mouth
  • Cramps
  • Muscle spasms
  • Fatigue
  • Headache
  • Stop sweating – if you have started sweating and then suddenly stop even though it is still hot and you are still working hard, this is a severe sign. Get hydrated.
  • Nausea / Vomiting

Add an Electrolyte

Remember that heat makes it more likely that you’ll get dehydrated, so be prepared. In the summertime it is wise to add an electrolyte to your drink to help with hydration as you sweat. Sweat is a combination of water and salt, so if we only add back the water, the body is missing the salt(sodium) necessary for proper hydration.

Potassium and sodium work together in the body to keep cells properly hydrated and blood volumes high. Make sure your electrolyte drink includes both sodium and potassium.


Consistent Hydration

Think of hydration as an IV – you should never feel the need to chug water, but instead be taking sips of water all throughout the day.

If you are going on a long run or a run in the heat, you may want to bring water or even an electrolyte drink with you on your run so that you can continue to take sips the entire time you are out.

There are several ways to carry water with you; from hydration backpacks with bladders, to water bottles that strap to your hand. Find what works best for you so that you don’t mind bringing fluids with you on our run.

Stay hydrated and have a great run!


**We are not doctors, you should consult with your doctor about proper hydration and ensure that electrolyte drinks and different levels of exercise are right for you.

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Post Author

Nicole Hillstead-Jones

RRCA Certified Coach & Nutrition Minor