Marathon Running and Race Support

3kg and 4 cm for 1 hour run!!! is this normal???


I have posted this in another forum (Weight Loss NHS) sorry for whoever else is on both... I would like other expert advice from runners...

I have never monitored my weight before and after runs. I do know that you lose liquids and all the rest, but this morning before going out for my daily run I looked at the scale and measures and I was 91 kg. 103 cm waist. I went out for 8 miles run which is about 1 hour for me and once back (after shower and a few glasses of water - at least 4) I looked at the scale again and surprise.. 88 Kg. ??? So I took the measuring tape and looked at it with even more surprise... 99 cm ??? I know for a fact that everything will be back to normal tonight (I won't keep this drop).

I need about 1100/1200 calories for the run, so I cannot lose more than 2-4 hg. of fat. I know liquid is important but is it possible that I have lost all these liquids? could it be (combined with my history of running and not losing weight) a sign of high liquid retention or food intolerance? Does anything else come up to your mind???

Anyway, it could be that this change in eating habit could help me get rid of this :)

so let's see what happens in a few weeks/months

have a great day


8 Replies

Err hmmmm err I wish I could say more.


It all evens out. Don't monitor from run to run or you will go mad. If you eat and drink healthily and keep,running regularly you will lose weight. Try and walk everywhere instead of taking the car. Get into good life long habits and the scales will be kind 😊


I'd say that's quite normal, I weighed myself last week before and after a 3 mile run and I had lost almost a kilo. That equates to a litre of fluids, You ran nearly 3 times as far, and lost 3 times as much water. I would be more concerned with staying hydrated than the weight loss.


I would be Looking more to am I hydrated enough during my run as I would imagine that sort of fluctuation is hydration related. Your lucky losing weight with running distances my body hates it and all weight loss stops the higher the distances go. Done two HM with no weight loss at all back to 5-7km and weight loss started again. Hehe we all are different.


I have a bad habit of leaping on the scales after a run and once I lost half a stone... dont underestimate how much fluid you lose... if it stays off then great!!! nice work :)


this was just to study a bit my body's reaction to run, I have never done it before and I am pretty sure it does not stay off (I have run 2500 miles on and off since 2014 and I gained a couple of kilos. I am now motivated to drop my weight to normal but it will take a while :)

thanks for the suggestion on hydration, it is important (even if I cannot run with a bottle, I have tried many time, I always and up trowing it away... )


Have you tried a bottle belt? I have one (not this particular model, it was just the first I found on Googling, and hey a discount!) and I find it fine to run with.


it CAN only be water loss.. you wont lose anything as fast ( or build it up as fast as that) once heard good tip for how to keep hydrated being weighing yourself before and after exercise- lose 1 kg = you need to drink 1 L to be fully hydrated.. so it seems you lost 3 L of water... if you cant drink while running id try and ensure you are well hydrated before it.. to minimise effects . and with that amount of loss i think you might need to think about salt loss during running too? drink milk afterwards to better rehydrate...


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