How much weight do you lose after

…a tough training session or maybe an event? Last two days I’ve weighed myself first thing in the morning and then after a run session, now admittedly it has been pretty warm. One was a steady 20km run the other was a 40 min 10km effort. Both times I’ve been 2 kg lighter! (73 to 71) Just quite surprised its that much, roughly 2 litres. I know from watching an MMA program that its pretty common practice to drop huge weight in bin bags suits etc to ‘make weight’. Anyway just curious what other people have noticed?

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Yeah that sounds about right.

I weighed myself yesterday morning before breakfast and then after my brick session and i’d lost 2kgs. That was after chugging 300ml of fluids when i got in, plus the additional weight i’d have been holding after my breakfast and snacking in the morning.

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Yeah I’ve lost this on a 1hr moderate run. More commonly 1kg.

It was shocking the first time I noticed, and I started drinking more on the run :slight_smile: Now I can’t arsed.

I think the dehydration can sometimes have a significant effect on blood pressure though - I saw my BP drop from 140 to 120 immediately after a sweaty run.

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I sometimes weigh after longer/sweatier efforts and then attempt to drink 1-1.5x the weight lost so I’m properly rehydrated.

That can’t have taken long!

Recovery shake innit.



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I have been 3kg down after a long run, 66kg from 69kg. Ran home from in-laws house cross country on a hot summer afternoon. Got lost in the fields and it was a bit more than 30km. Wasn’t super-well hydrated to start with.

For the last 10km I was eyeing up every puddle and stagnant brook. Seriously thought about knocking on a farm door and asking for water, but even in a thirst-addled state that felt a bit too weird. Was not a nice experience at all. Slowed down in the last 10km big time so definite effect on performance.


I drank 1.5l of BetaFuel, 4 x 66g gels and 500ml recovery shake yesterday during/after a 32km jog.

Went for a shower and weighed myself, 1kg lost.
Add the weight consumed and it’s over 3kg.

Easily done.


Tell you what though - those first 3 pints of Vimto when you get home - nectar :ok_hand:


Also sometimes up to 2kg.

Strangely, the next day I can be up to 2kg heavier but if I have a rest day then weigh myself then I’m usually back to normal.

2 rest days and unless I’ve been to the curry house or Dominos, I tend to lose a slight bit

My Zwift weight is basically what I weigh after 2+ hours in the heat :sweat_smile:


My Zwift weight is 55kg. Just call me Nairo


1.7kg lost on a 22km run

I did an Outlaw recce on a hot summers day with 2x750ml bottle. Third lap around 140km I was dropping and had to stop and ask for refills, wasn’t going to make it to the petrol station I was hoping for!

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I lost 500kg at work last year. Couldn’t find that bloody calibration weight anywhere.

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