Don't trust your thirst buds!!!! - Marathon Running ...

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Don't trust your thirst buds!!!!


I posted in the 10K forum about my recent HARD "crash and burn"/ "hit the wall" experience at the 19K mark of an intended 24 klm run. Considering that this run was done at a pace over 1 minute slower than a previous 20K run - why did I crash in this one? I have always thought that if I ever did "hit the wall" in the way it is commonly described after around 2+ hours of running , I would simply walk the rest of the distance. yesterday I had to ring for my wife to pick me up - I told her where I would be - sitting on a seat at the bottom of a long hill. I was at the top of the hill when I rang her and thought, because I was disappointed to be feeling this way, I would "jog" to the bottom of the hill. I could not do it!!! - I was truly finished and was barely able to walk down that hill to the appointed pickup place.

It was a warm and extremely humid day and my perspiration levels were through the roof - I have never been so "wet" at the end of any other run - and I had drunk less than 500 mls over the 2.5 hours. So - upon reflection I can now see what my problem was, severe dehydration. BUT - I was never once "thirsty" during the run in spite of the heat , humidity and my (now) obvious levels of perspiration.

6 Replies

Yep it would appear they led you astray. Even though you didn't feel thirsty it was odds on that you would dehydrate given the hot weather and the fact you were sweating freely. Makes sense to replace lost fluids and minerals but I suppose sometimes we just forget to take a drink or get a bit blase about it.

I did run into trouble on a hot day on the canal last summer. No drink and no cash to buy one. It was like the ruddy sahara. I thought I'd have to drink canal water. Gasp


No, never rely on your thirst buds. I just regularly replenish every 2K. I had a bad experience at my first HM where despite drinking, I clearly wasn't drinking enough, and ended up not perspiring at all and getting the chills. From what I read online, it was probably some form of heat exhaustion. Since then I've done my best to avoid this happening again.


I think it's comparable to "fuelling". Once you feel hungry and that you need energy it's too late, because you have already spent your clycogen and it takes time to process food. Or the feeling of needing a walking break - as we know from Mr. Galloway, the effective way of recovering is to recover before we're knackered.

Same thing with feeling dehydrated. Once it hits, it's too late to really to address it in a way that will allow us to carry on.

It's great that you had the option of ringing your wife. Dehydration can be dangerous.


As well as regulating your water intake you could look into gel packs that you can consume on your runs to give you a bit if a boost.

I know in gym work it is recommend that we consume up to 500ml of water for every 30 minutes of a hard rigorous workout, would it be similar for running or would it be to much over a long distance?


Gosh that must have been awful, and when you have sorted your hydration focus on the mental repair of having that experience. I hope it hasn't set you back too much, you are doing so very well 😎

mfamiliasHalf Marathon

Eeep, sounds awful. I'm glad you got home safely. It's my fear when running - keeling over into a ditch and not being found. I was in a similar situation this morning and realised that my lips were dry and my head was woozy. Then realised that given the distance planned, I should have taken some form of sustenance with me and something to drink. Lesson learned and confirmed by your timely post.

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