9 Signs of Dehydration in Runners

As I write this, I’m looking out the window at a bright, sunny, hot day in Texas.  It’s only the beginning of summer and summer temperatures, which means it’s the beginning of the most challenging training season for me personally.  Running in the summer, especially in hot temperatures, means fine tuning your own hydration plan and system.  If you are new to running, know that you NEED to have a hydration plan if you are going to run in the summer.  There’s lots of ways to do this – timing, heat mitigation, what you wear, etc., but it all really boils down to making sure that you stay hydrated.  And that doesn’t just mean drinking enough water.  It also means staying on top of electrolyte balance and sodium replacement.  

It happens to us all, no matter how much we train and prepare: dehydration.  Struggling due to lack of hydrating properly, including not enough electrolytes.  To improve upon your own hydration plan as a runner (and avoid having to completely give up running in the summer), the first thing you need to do is be aware of the signs of dehydration.  Knowing what to look for is one of the first steps to knowing how to combat it.  Here’s some big red flags to watch for: 9 signs of dehydration in runners!

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9 Signs of Dehydration For Runners

Running in the summer can be completely freeing (it’s incredibly rewarding to not have to give up your hobby for an entire season), but you need to know what you are up against.  If you experience any of these 9 signs of dehydration, you need to do more fine tuning of your hydration plan while running.

1. Decreased Performance – this can be caused by several things, of course (signs of overtraining, lack of sleep, lack of nutrition, common running injuries), but dehydration can be a culprit, especially in the summer.  If you are struggling to hit your normal pace or effort level (and there are no other obvious culprits to blame), it could be dehydration.
2. Fatiguing Earlier – feeling *unusually* tired early on in a run or workout.
3. Muscle Cramps – this is a big red flag that your electrolyte balance could be off. Sodium, potassium, and magnesium work together to keep your muscles functioning. Dehydration can cause you to lose all 3.
4. Headaches – headaches can occur due to dehydration (even when not running or working out), but you may notice them more after a long running or workout effort.  
5. Dizziness or Lightheadedness – you may notice this sign of dehydration more when you are standing up quickly, for example, but you should not try to push through this one.  Dizziness or lightheadedness is caused when your blood volume drops, which makes it harder for oxygen to reach your muscles.  Thus the feeling of lightheadedness.
6. Dry or Sticky Mouth – this sign of dehydration is a little more subtle than muscle cramps, headaches, or dizziness, but it can be an early warning sign that your body needs more.
7. Extreme Thirst – this is an obvious one, but one you shouldn’t ignore. It means you’re already falling behind on your hydration.
8. Elevated Heart Rate or Rapid Breathing – even at moderate levels of exertion, dehydration can cause your heart to have to work harder, which increases your heart rate and breathing.
9. Dry Skin / Lack of Sweat – this is a sign of severe dehydration and overheating. Not being able to sweat efficiently raises your risk of heat stroke and other heat related illnesses.

How to Prevent Dehydration in Runners

As an athlete and a runner, I’m sure you want to keep going during the summer.  But if you are dealing with any of these 9 signs of dehydration, you need to address them, especially if this is an ongoing problem you’re noticing on all your hot weather runs.  

1. Water alone isn’t going to cut it – you’re going to come up short if you try to run in 100 degrees on just water alone.  You need to supplement your water intake with something that also addresses your electrolyte balance.  Whether that’s a drink mix like LMNT, Tailwind, or Skratch (my personal favorite), or salt tablets or electrolyte chews (I like the Salt Stick buffered salt tablets and Salt Stick lemon lime electrolyte chews), you need to be doing a little extra. I also like to sometimes supplement with a little coconut water for extra natural electrolytes, and pickle juice shots!  Also, don’t forget that you can also address electrolyte and sodium balances with some salty snacks too, if you lean towards real food for running fuel.  Things like pretzel bites, olives, boiled and salted baby potatoes, etc.  
2. It needs to sound good – there are a lot of ways to supplement, but it HAS TO SOUND GOOD to you, not just good on paper! Just because your friend raves about LMNT, doesn’t mean it’s going to work wonders for you.  In my case, many electrolyte drink mixes cause upset stomach.  You need to TEST EVERYTHING OUT yourself, and it has to sound good on a hot run.  If it doesn’t sound good, you’re not going to use it.  Remember, it’s harder to fuel when it’s a hot workout.  You need to practice this (and it may take a little time to perfect).
3. Address other factors – besides hydration, be sure that you are mitigating heat in other ways as well.  This could be running earlier in the morning, running on a more shaded route, and wearing the right fabrics.  
4. Before, during, and after – don’t just chug a bottle of water right before your run.  If you are running in heat, you need to hydrate before (including electrolytes), during, and after a hot run.
5. Monitor urine and thirst levels – dark urine and increased thirst levels need to be addressed.  These can be signs that you need to hydrate more before you even start on that run.
6. Have enough water – this may sound obvious, but it does require some intentional planning. For longer runs or less “supported” runs (like remote trail runs), you may want to invest in a hydration bladder or collapsible flasks in a hydration vest.  Make sure that whatever you use, you have a way to carry enough or refill often, drink easily and often, and have your water and electrolytes easily accessible.

Dehydration is not just an annoying little side effect of running in heat.  It can be a serious health problem, as well as seriously holding you back on your own progress.  Knowing how to spot and prevent dehydration can allow you to continue on running during the hottest months of the year, safely and responsibly.  In Texas, where the summers and the heat last for 6 or 7 months, it’s an area I am constantly working to improve upon and fine tune.  Being able to stay strong and run in the summer has been one of my own proudest accomplishments as a runner!

Check out these other running related resources – including tons of FREE training calendars for all distances!

And don’t forget, I now offer 1:1 Consults for Beginner Runners – develop individualized training calendars, discuss baselines, goals, and steps, talk injury prevention and gear recommendations, and develop an effective hydration and fueling plan.  These are just a few areas I address in my 1:1 Consult Plans – reserve your spot here!  

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