How to Spot the Symptoms of Dehydration When Running

Posted on

Running often pushes you past your comfort zone and, done in a safe way, this can lead to performance gains. Pushing yourself to the limit is the basis of many training programmes!

However, there is a difference between pushing yourself safely and going too far. Once the temperatures increase, we need to account for the heat in our approach to training and racing. If not, you may find yourself succumbing to the symptoms of dehydration. 

I once suffered from this at the end of a hot and hilly 10 mile race and I can tell you, it wasn't pleasant and the symptom came out of no-where. Immediately after crossing the finish line I felt fine, however after a few minutes I felt like I just needed to sit down in the shade. And then needed to quietly lie down. Next thing I knew I had a doctor perched over me forcing fluid down my throat (the race didn't have any IV fluids to hand) and telling me to fight the urge to pass out as then I wouldn't be able to drink and things would get much worse. I hovered on the edge of consciousness for just long enough to drink gallons of sports drink and after about 90 minutes started to feel less ill.

Where I went wrong that day was drinking too much in the morning - I just weed it all out before the race and then not drinking enough during the race.

How to Spot Dehydration:

1. Thirst. Sounds obvious but ensure that you are prepared and have an electrolyte infused drink to hand.

2. Headache - never a good sign especially whilst running. 

3. Tingly hands and feet - this was what I had and to this day, if I'm running and the tingles start, I stop straight away.

4. Dry mouth - if your mouth is constantly dry then chances are you're starting to become dehydrated.

5. Muscle cramps - like many of these symptoms, cramp can occur even when not dehydrated but when combined with the other symptoms is a sign that you are.

6. Feeling light-headed or confused - if this happens you need to stop immediately, rest, breathe long deep breaths and have a drink.

Enter your email below to get 10% off your first order

You’ll receive an email - click confirm (takes 2.2 seconds) and you’ll receive your code.

No email? Contact us at

performance underwear
★ Read Our Reviews

Let customers speak for us

243 reviews

These socks are the best running socks I have ever purchased

Good service, product is fit for purpose

Service is great, and the boxer shorts are good for running and so the job they are designed for. Little disappointed that they are not ethically sourced, they have a cheapish feel to them which was a surprise.

Thank you for your feedback Duncan. Runderwear's range of seamless underwear has sustainability benefits over cut and sew garments by reducing wastage of fabric at manufacturing stage. We are testing new fabrics that have been made using sustainable fibers and aim to bring these into our range in the near future. All our factories are quality control checked to the highest standard and our small team regularly visit them and are satisfied that working conditions are ok. We are somewhat surprised you find the pants have a cheapish feel to them. But maybe you mean that the material is not thick and when you stretch it and look up-close it has an almost gauze-like appearance; this is the nature of the product and gives it the moisture wicking properties. We hope you will like using them and will realize how comfy they are.



Super comfy and stay in place. U.K. size 10 and ordered small.

Women's Running Long Shorts
Cassandra Kay-Lewis
At last... chaff free running.

Had just about given up with the belief there were running shorts out there that don’t chaff. Purchased the long shorts, and have to say they are wonderful. They are stable, breathable, comfortable and total chaff free.
I would like to highlight I was under the impression that these were “proper” shorts, however they could possibly be described as a base layer shorts. Some form of lightweight run shorts are recommended to wear over them to cover your modesty. Wearing my lightweight run shorts over the top of them didn’t detract from the long shorts benefits.
I typically run up to 21km.