How many calories does cycling burn?

winnie1966

i've been a bit bored so i was looking at average calories burned per hour cycling and the consensus is about 500 per hour ....yes i know that can vary significantly depending on alot of factors but average person at about 12 mph on roughly flat road will burn roughly 500 Cals apparently. Now unless my old university physics education is wrong that would equate to a power of >500 Watts!!!!!

i must be missing something.

Calculation below
1 Cal = 4.184 KiloJoules
500 Cal = 2092 KiloJoules
500 Cal/hr = 2092 KiloJoules/Hour = 2092000 J/Hr = 2092000/3600 J/S = 581 J/S
1 J/S = 1 W
So 500 Cals in 1 hr means an average of 581W

This must be incorrect - can anyone enlighten me ?

VamP

winnie1966 wrote:

i've been a bit bored so i was looking at average calories burned per hour cycling and the consensus is about 500 per hour ....yes i know that can vary significantly depending on alot of factors but average person at about 12 mph on roughly flat road will burn roughly 500 Cals apparently. Now unless my old university physics education is wrong that would equate to a power of >500 Watts!!!!!

i must be missing something.

Calculation below
1 Cal = 4.184 KiloJoules
500 Cal = 2092 KiloJoules
500 Cal/hr = 2092 KiloJoules/Hour = 2092000 J/Hr = 2092000/3600 J/S = 581 J/S
1 J/S = 1 W
So 500 Cals in 1 hr means an average of 581W

This must be incorrect - can anyone enlighten me ?

You're assuming 100% efficiency, in fact it's closer to 20 - 25%

winnie1966

thank you - that makes perfect sense now and the number fit too - about 100W - much appreciated

cougie

500 calories for an hour of 12mph sounds very high to me.

I know it's about 100 calories a mile for me running so a fairly gentle run would be about 600 calories and cycling is much easier.

neeb

It's a nice coincidence that very approximately, our metabolic & mechanical efficiency (chemical energy we burn to produce a given amount of mechanical energy) is about the same proportion as the conversion factor between a KiloJoule and a KCal. So if your power meter tells you that you've produced exactly 1000 KiloJoules then you've burned not far off 1000 KCal.

milemuncher1

23 per mile, is a good guestimate. It’s dependent on effort and duration, and the individual rider, and how their metabolic system is functioning, but 23 cals per mile, is reckoned to be not to far wide of the mark, for an average joe, making an average effort.

neeb

cougie wrote:

500 calories for an hour of 12mph sounds very high to me.

I know it's about 100 calories a mile for me running so a fairly gentle run would be about 600 calories and cycling is much easier.

I climbed Alpe d'Huez on BigRingVR the other night - it took 59m37s at an average of 245w and Strava estimates I used 977 Calories. So to burn 500 Calories I'd have to do it at about 125w. Not sure how fast you'd go If you held 125w on a flat road - maybe 12mph isn't that far off for someone on an upright shopping bike?

imposter2.0

As Vamp implied earlier - unless you can accurately measure power/duration - and unless you have a detailed number which you can pin on your GME, then anything else is just going to give you some mildly-entertaining random guesswork..

pinno

neeb wrote:

It's a nice coincidence that very approximately, our metabolic & mechanical efficiency (chemical energy we burn to produce a given amount of mechanical energy) is about the same proportion as the conversion factor between a KiloJoule and a KCal. So if your power meter tells you that you've produced exactly 1000 KiloJoules then you've burned not far off 1000 KCal.

Interesting.

The only downside is that I don't have a power meter. The upside is that i'm not as fat as itboffin. He's the yardstick but not DanielB - he's the stick and i'm not as fit as Gilbert - he's the carrot.

neeb

Imposter wrote:

As Vamp implied earlier - unless you can accurately measure power/duration - and unless you have a detailed number which you can pin on your GME, then anything else is just going to give you some mildly-entertaining random guesswork..

Although if you know power/duration exactly and you make the reasonable assumption that your GME is between 20 and 25%, the KCal estimate should be within 20% or so, which gives you a good enough ballpark figure for thinking about eating to replace energy burned.

burnthesheep

neeb wrote:

Imposter wrote:

As Vamp implied earlier - unless you can accurately measure power/duration - and unless you have a detailed number which you can pin on your GME, then anything else is just going to give you some mildly-entertaining random guesswork..

Although if you know power/duration exactly and you make the reasonable assumption that your GME is between 20 and 25%, the KCal estimate should be within 20% or so, which gives you a good enough ballpark figure for thinking about eating to replace energy burned.

Two books I have quote the 20-25% range. It claimed the less athletic you are the less efficient, I think I recall that in there.

Since the math is 4-1 on efficiency and 4-1 on KJ to cal..........the simplest way is to take power meter KJ's from a ride and call it 1:1 for your calories.

Strava and my Elemnt take my KJ though and somehow inflate it usually above the KJ number for the calories. Yesterday was 1063 KJ vs 1185 cal. Whatever.

But, this also gets into calorie counting. For me, personally, that isn't sustainable. I wouldn't last a day doing that. All I can do is the training I want to do that will make me faster. Then, eat some better choices to properly fuel it and cut out some excess night time treats. I do look at KJ for an EM ride to make sure I met the intent of time/work versus the plan.

pinno

burnthesheep wrote:

neeb wrote:

Imposter wrote:

As Vamp implied earlier - unless you can accurately measure power/duration - and unless you have a detailed number which you can pin on your GME, then anything else is just going to give you some mildly-entertaining random guesswork..

Although if you know power/duration exactly and you make the reasonable assumption that your GME is between 20 and 25%, the KCal estimate should be within 20% or so, which gives you a good enough ballpark figure for thinking about eating to replace energy burned.

Two books I have quote the 20-25% range. It claimed the less athletic you are the less efficient, I think I recall that in there.

Since the math is 4-1 on efficiency and 4-1 on KJ to cal..........the simplest way is to take power meter KJ's from a ride and call it 1:1 for your calories.

Strava and my Elemnt take my KJ though and somehow inflate it usually above the KJ number for the calories. Yesterday was 1063 KJ vs 1185 cal. Whatever.

But, this also gets into calorie counting. For me, personally, that isn't sustainable. I wouldn't last a day doing that. All I can do is the training I want to do that will make me faster. Then, eat some better choices to properly fuel it and cut out some excess night time treats. I do look at KJ for an EM ride to make sure I met the intent of time/work versus the plan.

If you want to loose weight, It basically boils down to the simple equation of more calories burnt than consumed.

fenix

And its a lot easier to not take the calories in than it is to burn them off through exercise. It takes minutes to eat the calories for hours of exercise.

neeb

I simply use the very approximate estimation of calories burned from power data to reassure myself that I’m not overeating when I come back from a long/hard ride and feel the inclination to stuff my face.. If I’ve just burned something in the region of 2000 KCal I can eat a big pizza for dinner and still be in calorie deficit relative to my normal daily energy intake and expenditure..

fenix

Power meter data is probably OK but Strava estimations are ridiculously high.

aberdeen_lune

I would think 23 calories a mile is too low more like 32. So for a 25 TT you would burn 800.

The other aspect is the increased burn overnight after your metabolism has been raised and the repairs required to your muscles. So the total cost of a 25 TT got example would be way more than 800 calories.

neeb

Fenix wrote:

Power meter data is probably OK but Strava estimations are ridiculously high.

Yes, they’re too high but not by a really massive amount. Based on the figures above it seems that Strava is assuming a metabolic efficiency of 26.6%. The kJ figure from the power meter should be completely accurate however, or at least within the accuracy of the meter (1 or 2%).

neeb

neeb wrote:

Fenix wrote:

Power meter data is probably OK but Strava estimations are ridiculously high.

Yes, they’re too high but not by a really massive amount. Based on the figures above it seems that Strava is assuming a metabolic efficiency of 26.6%. The kJ figure from the power meter should be completely accurate however, or at least within the accuracy of the meter (1 or 2%).

Actually, no, I got that wrong.
1kCal = 4.184 KJ

Yesterday was 1063 KJ vs 1185 cal. Whatever.

1063 KJ = 254.06 kCal actually put out through the pedals.
Strava is estimating kCal burned as 1185, i.e. 4.664 x 254.06 due to metabolic inefficiency. That's assuming 21.44% efficiency I guess? So a little on the low side but within the 20-25% range. But if it's biasing towards the low end of efficiency then it is indeed likely to be overestimating kCal burned, but not by much.

And as Aberdeen_lune points out, you will also be burning some kCal afterwards, so biasing towards a slightly higher kCal estimate is arguably reasonable. You are AT LEAST burning the number of kJ put through the cranks corrected for your metabolic efficiency.

pinno

neeb wrote:

And as Aberdeen_lune points out, you will also be burning some kCal afterwards, so biasing towards a slightly higher kCal estimate is arguably reasonable. You are AT LEAST burning the number of kJ put through the cranks corrected for your metabolic efficiency.

You're talking about the latent effect of the body burning fat after exercise?

neeb

Pinno wrote:

neeb wrote:

And as Aberdeen_lune points out, you will also be burning some kCal afterwards, so biasing towards a slightly higher kCal estimate is arguably reasonable. You are AT LEAST burning the number of kJ put through the cranks corrected for your metabolic efficiency.

You're talking about the latent effect of the body burning fat after exercise?

Yes, although not necessarily fat. For a period after exercise your metabolic rate is raised a bit because you are replacing glycogen / repairing muscle / doing other stuff to offset the impact on your body of the exercise. Some of this ongoing increased energy expenditure is already factored into the energy you burned to do the work (i.e. the energy required to replace the glycogen you already burned), but much of it isn’t and is further energy burned on top of what you used to do the work.

burnthesheep

Careful on the dinnertime treat from a hard/tough ride.

Isn't that the worst time to reward eat since you're about to sleep anyway? Maybe a balance of the treat between dinner and the next breakfast?

I swear I saw that somewhere. To avoid biasing your caloric intake heavily to night time or dinner time.

That makes me sad if true, dinner is my favorite meal. Even dessert or cake be damned, I like the meal itself instead. I fancy a good curry as a treat. Some samosas, naan, fragrant rice, and lamb or chicken curry.

neeb

burnthesheep wrote:

Careful on the dinnertime treat from a hard/tough ride.

Isn't that the worst time to reward eat since you're about to sleep anyway? Maybe a balance of the treat between dinner and the next breakfast?

I swear I saw that somewhere. To avoid biasing your caloric intake heavily to night time or dinner time.

That makes me sad if true, dinner is my favorite meal. Even dessert or cake be damned, I like the meal itself instead. I fancy a good curry as a treat. Some samosas, naan, fragrant rice, and lamb or chicken curry.

Well, I've been heavily biasing my caloric intake towards late evening all of my life and I'm 63kg at 51yo. If you've used energy you need to replace it (assuminmg you are not trying to lose weight). I guess it's something to do with what your body does with excess energy while you are sleeping as opposed to when you are awake, but if it's not excess it shouldn't matter, it'll be reconverted to whatever it needs to be in due course.

I've noticed though that if I eat too much at night when I haven't expended much energy during the day I sometimes don't sleep very well and I get too warm in bed at night. My theory is that my metabolism is genetically programmed to burn off excess energy as heat at night by upping my metabolic rate, and that's why I generally find it not too hard to keep the weight down.

pinno

neeb wrote:

Pinno wrote:

neeb wrote:

And as Aberdeen_lune points out, you will also be burning some kCal afterwards, so biasing towards a slightly higher kCal estimate is arguably reasonable. You are AT LEAST burning the number of kJ put through the cranks corrected for your metabolic efficiency.

You're talking about the latent effect of the body burning fat after exercise?

Yes, although not necessarily fat. For a period after exercise your metabolic rate is raised a bit because you are replacing glycogen / repairing muscle / doing other stuff to offset the impact on your body of the exercise. Some of this ongoing increased energy expenditure is already factored into the energy you burned to do the work (i.e. the energy required to replace the glycogen you already burned), but much of it isn’t and is further energy burned on top of what you used to do the work.

I was aware of all that and have posted similar on another part of the forum. Although trying to explain to a female at the sauna why she was feeling very hungry and not loosing weight after 3 aerobic sessions per week at only 30 mins per session was tricky. :roll:

diy

I imagine she was thirsty and her brain confused it with hunger..
Roughly it takes about 3,300 kcal to burn 1 lb of human fat. But taking into account EPOC etc. 1 hour of hard mixed cardio could give you roughly another 6-8% on top. So your 600kcal session could get you another 40 or 50kcal on top.

If the goal is fat burning / weight loss, its better to do 1 hour of zone 2, than 20 mins of zone 4.

What I did find surprising is even active people burn as much as 40% of their kcal while sleeping so the old myth that its better not to eat before sleep isn't applicable to people who exercise a lot.

kingpinsam

Aberdeen_lune wrote:

I would think 23 calories a mile is too low more like 32. So for a 25 TT you would burn 800.

The other aspect is the increased burn overnight after your metabolism has been raised and the repairs required to your muscles. So the total cost of a 25 TT got example would be way more than 800 calories.

This is the guide I use assuming 25% efficiency,

It's about 200W to do 20mph on the flat on a road bike, that's 800 cal/hour = 40 per mile, so 1,000 cals for a 1 hour 15 min 25mile TT

300W for ~ 25mph would be 1200 cals an hour = 48 a mile.

aberdeenal

I burn 580 cals per hour cycling - this seems to correlate with figures from my VO2 max test and also medical testing at my wife's work.

milemuncher1

kingpinsam wrote:

Aberdeen_lune wrote:

I would think 23 calories a mile is too low more like 32. So for a 25 TT you would burn 800.

The other aspect is the increased burn overnight after your metabolism has been raised and the repairs required to your muscles. So the total cost of a 25 TT got example would be way more than 800 calories.

This is the guide I use assuming 25% efficiency,

It's about 200W to do 20mph on the flat on a road bike, that's 800 cal/hour = 40 per mile, so 1,000 cals for a 1 hour 15 min 25mile TT



300W for ~ 25mph would be 1200 cals an hour = 48 a mile.

I agree that those numbers sound about right, but ‘average joe’ wouldn’t be putting down 300W for an hour.