Calories burnt during a ride

[esoxlucius]

I went out for a ride this morning and before putting all my gear on I weighed myself naked at 10st 10lb on the nose.

During the ride I had a couple of swigs of my drink, about 100ml, weighing about 4oz. So that stood me at about 10st 10lb 4oz.

When I got back I stripped and weighed myself again at 10st 8lb 12oz. The bike ride, even factoring in the weight of the drink, had taken 1lb 8oz off me.

I believe that, at 3600 calories per pound, that 1lb 8oz equates to about 5400 calories. Yet my cycling computer said I'd burnt 1096 calories!!!!

I am aware that cycling computers can be a bit hit and miss with calorie counts so I I'm highly dubious of the 1096 figure.

What amazes me is that, if my figures are correct and I'm understanding it properly, that 5400 figure just seems so ridiculously high for what was only a 40km, hour and a half, 26kph average speed journey.

Can anyone shed any light on this? My bathroom scales by the way are spot on.

 

[fossyant]

Your figures are wrong, and you've also not drank enough - for an hour and a half you want to drink a full bottle of water.
Even if you weigh yourself at the same time every day, weight can vary by a few kg's depending upon hydration.

That drop in weight will be dehydration. 1000 cals is more accurate for an hour and a half riding

 

[esoxlucius]

Your figures are wrong, and you've also not drank enough - for an hour and a half you want to drink a full bottle of water.
Even if you weigh yourself at the same time every day, weight can vary by a few kg's depending upon hydration.

That drop in weight will be dehydration. 1000 cals is more accurate for an hour and a half riding

I usually do drink a lot more but during the cooler months never seem to want as much whilst on the bike, plus I hydrated beforehand anyway.

So the cycle computer seems to be more accurate than I give it credit for?

 

[fossyant]

The computer is only guessing also, but 5400 cals is way over - you'd be looking at 5 plus hours riding for that.

 

[N0bodyOfTheGoat]

~600 Calories per hour is very typical for an average road bike cyclist iirc.

A bit higher on hilly rides, especially if you attack the hills near full beans.

Bit lower on pancake flat routes and keeping effort below zone 3.

While heavier riders like me at ~95Kg these days would need to burn more Calories on a rolling route than lightweight riders like you under 70Kg.

 

[sevenfourate]

~600 Calories per hour is very typical for an average road bike cyclist iirc.

A bit higher on hilly rides, especially if you attack the hills near full beans.

Bit lower on pancake flat routes and keeping effort below zone 3.

While heavier riders like me at ~95Kg these days would need to burn more Calories on a rolling route than lightweight riders like you under 70Kg.

I’m 90-95kg too. My calories / Watts are considerably higher than most I ride with for same speed / duration because of that. I have more fun than them keeping nutritionalised though 🤣🤣

 

[Webbo2]

My Wahoo bolt gives quite a high calorie count when it’s going off my heart rate monitor. Todays ride 4 hours 32 minute 3,951 calories. However when I use my power meter it’s much less as shown by a ride a week ago 4 hours 39 minutes calories 2007. Similar climbing on both rides.

 

[presta]

I thought the official view of this forum is that cycling doesn't burn any calories at all. Or does that argument only apply when I draw people's attention to the cost of the food, or the CO2 emitted in producing it?

You cannot possibly make an accurate measurement over a period as short as one day, because the confounding variables are too large and the variation you're trying to measure is too small. The point here is that the confounders are not cumulative, and the total energy consumed by exercise is, so if you make the measurement over a long period of time the accuracy improves in leaps and bounds.

I've been recording my daily exercise, weight, and calorie intake for over 20 years, and the data I get is a pretty good match for that published in the American College of Sports Medicine Compendium of Physical Activity, which is all based on accurately measured scientific data, and the standard reference for the scientific community.

My bathroom scales by the way are spot on.

You're sure about that, are you? All the scales I've ever stood on give a different reading each time you step on them, and a different reading if you rock your weight side to side, or fore and aft. To get any meaningful data you need to average multiple readings over the long term to minimise the effect of confounding variations.

 

[Webbo2]

Doesn’t a power meter give a reasonably accurate measure of energy used as it records KJ’s

 

[N0bodyOfTheGoat]

Doesn’t a power meter give a reasonably accurate measure of energy used as it records KJ’s

They should give a good ballpark number.

 

[esoxlucius]

You're sure about that, are you? All the scales I've ever stood on give a different reading each time you step on them, and a different reading if you rock your weight side to side, or fore and aft. To get any meaningful data you need to average multiple readings over the long term to minimise the effect of confounding variations.

Very sure. The secret to accurate readings with usually unreliable bathroom scales is basically what you said. Weigh multiple times, on a hard flat surface, and keep still! I calibrate mine periodically too with 1kg, 5kg and 10kg weights.

 

[Dogtrousers]

The bike ride, [...], had taken 1lb 8oz off me.

Thats 680g. A bit over one bidon (550g). The weight change over the ride will all be liquid.

My weight varies by more that much during a typical day when I'm not doing anything of note.

500-600 kcal per hour, give or take is a decent finger in the air figure, but rider weight, terrain, relative effort etc will all make a difference.

 

[Punkawallah]

Did you weigh the same if you weren’t on your nose?

 

[wafter]

All the scales I've ever stood on give a different reading each time you step on them, and a different reading if you rock your weight side to side, or fore and aft. To get any meaningful data you need to average multiple readings over the long term to minimise the effect of confounding variations.

Or, even better defaulting to the last measured value if the current measured value is within a certain range to make their readings appear more repeatable...

I can get mine to vary by maybe 100-300g by "resetting" them between full readings by applying a partial weight to them. Otherwise if I repeatedly get on and off them they remain the same. They will also insistently stick to the last reading even if something has changed; like going for a sizeable crap.

All that said I can't complain too much as I did find them propped up against the bin by the village hall

 

[nogoodnamesleft]

Water loss (from skin and in breaths).