Body weight & sweating & calculating W/kg

Hey TRers:

So I sweat a lot – sometimes for a 90min endurance ride I lose about 3kgs of water weight. So I would go from 75kg to 72kg. One day I actually went from 74kg to 70kg…

I do tend to retain water quite well (blessing and curse) especially after dinner and I’m always weighing myself the next morning before and after the workout. And I’ve read somewhere that sweating is part of endurance adaptations.

My question is then – what should I benchmark my bodyweight at for my bodyweight on TR?


Measure and record weight whenever it’s possible to be most consistent about it. Usually this means in the morning.

Don’t measure your weight (for this purpose) after a workout, you’ll have lost some unknown amount of water.


I’m the same way. I’ll come back from a 5 hour ride 5lbs less than when I left even though I’m constantly eating and drinking.

Be consistent. I suggest the second you wake up. I wake up, pee, get on the scale. Every morning.

just a sidenote… if you sweat 4 kg of water in 90 min, you really should thinking about investing in a better fan… or several better fans :sweat_smile:

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Makes no difference. The fans just evaporate the water faster.

This is speaking as a guy who is also capable of losing 4KG in a 2 hour indoor ride.

Benchmark your bodyweight when you first get up in the morning, it tends to be the most consistent. Do it every day and you’ll soon realise that it will fluctuate quite a bit from one day to the next - as much as 2kg in my case. It’s the long term trend you’re interested in, not the number on any given day, let alone at different times on the same day. E.g. if over the space of 6 months your weight goes from falling into the 73-75kg range in the morning to falling into the 70-72kg range, you’ve lost ~2kg.

My assumption is that when people put their weight into their TR profile, or post weight or W/kg numbers on the forum, they are at best using the lowest weight recorded in the last week, and quite likely in many cases using the lowest number recorded in the last decade…

isn’t that the point? Faster evaporation means more cooling, which should mean less sweating… It’s quite crazy the amount of heat the body produces. I mean the TR guys all use two of those Lasko fans… that’s an insane amount of airflow… it shows what is necessary for adequate cooling.

But more on topic: I bought a withings wifi scale 2 month ago and weighted myself daily every morning… I was quite surprised how much weight actually fluctuates… it can easily be 1-2 kg from day to day… and probably the same over the course of a day… so I thing it’s best not to get to hung up about exact weight. At the moment my weight bounces around 65-67 kg… so I put 66 in Trainerroad :man_shrugging:t2:
If it starts to be more consistently between say 64 - 66 I’ll probably change the TR weight to 65.

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I’m not sure about your question. Right now, weight in TR is largely irrelevant, so it really doesn’t matter whether you input your pre- or post-workout weight. For more general tracking, I try to take a reading on a recovery day when things are relatively “normal.”

Weigh yourself consistently, and not in a dehydrated state. First thing in the morning, before breakfast usually works for most.


The enemy of a good plan is the dream of a perfect one

My problem is that I workout very early in the morning, and all the stuff I eat the previous night is probably not properly digested. And depending on how much many KGs I lose once I get out of the bed in the toilet :stuck_out_tongue:

I’m purely just curious about what people have been doing. For me I know I do need to replace the salt lost during the workout throughout the day otherwise the second day will be miserable…

it really doesn’t matter as long as your consistent so you can see trends. You’ll be +/- a pound MAYBE 1.5lbs if you ate a lot the night before.

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Ha that’s an understatement! It’s more like 4-5 lbs for me!