Calories and cycling
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Have you ever tried to go fast on a bike? Drag becomes the dominant form of resistance somewhere in the range of 8-10mph. At 17mph or so, which is probably the cruising speed necessary for a 15mph average with stop-and-go, it'll account for 70%+. Do you think that it warrants inclusion, then, in our first approximation? Maybe?
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#355
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Taken out of context, the first statement is indeed incorrect, although perhaps not absurd.
If you believe that the second statement
is 'absurd', then honestly I'm at a loss.
If you believe that the second statement
It's a question of which terms we choose to neglect in our first approximation.
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And with that, I'm done with this discussion. By all means continue to retcon and shift goal posts, but the notion that speed doesn't matter w/r/t to energy expenditure is laughable and just plain wrong. Ta ta.
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Just comparing some power meter data from 2 identical loop rides on consecutive days, but at different average speeds:-
Ride 1: Distance 26 km, Av Speed 23.4 kph, Wind speed 26.1 kph SW, Total Work 440 kJ
Ride 2: Distance 26 km, Av Speed 27.1 kph, Wind speed 20.8 kph SSW, Total Work 557 kJ
So for an increase in average speed of just 3.7 kph, Total Work done increased by over 26%
There were no stops in either ride.
Ride 1: Distance 26 km, Av Speed 23.4 kph, Wind speed 26.1 kph SW, Total Work 440 kJ
Ride 2: Distance 26 km, Av Speed 27.1 kph, Wind speed 20.8 kph SSW, Total Work 557 kJ
So for an increase in average speed of just 3.7 kph, Total Work done increased by over 26%
There were no stops in either ride.
#362
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Just comparing some power meter data from 2 identical loop rides on consecutive days, but at different average speeds:-
Ride 1: Distance 26 km, Av Speed 23.4 kph, Wind speed 26.1 kph SW, Total Work 440 kJ
Ride 2: Distance 26 km, Av Speed 27.1 kph, Wind speed 20.8 kph SSW, Total Work 557 kJ
So for an increase in average speed of just 3.7 kph, Total Work done increased by over 26%
There were no stops in either ride.
Ride 1: Distance 26 km, Av Speed 23.4 kph, Wind speed 26.1 kph SW, Total Work 440 kJ
Ride 2: Distance 26 km, Av Speed 27.1 kph, Wind speed 20.8 kph SSW, Total Work 557 kJ
So for an increase in average speed of just 3.7 kph, Total Work done increased by over 26%
There were no stops in either ride.
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[QUOTE=GhostRider62;22179269] /QUOTE]
Funny, I thought you were an old man. Turns out that you're a teen from 4chan. Or could it be that you actually are an old man, just one who acts like a lonely incel teen posting memes and trolling strangers on the internet? Nahhh, that would be just too sad.
Funny, I thought you were an old man. Turns out that you're a teen from 4chan. Or could it be that you actually are an old man, just one who acts like a lonely incel teen posting memes and trolling strangers on the internet? Nahhh, that would be just too sad.
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[QUOTE=david101;22179278]
What is 4chan.
As far as trolling, you are the one enjoying spreading misinformation. What you wrote is just wrong, pure and simple. That you enjoyed the ongoing banter tells me who the troll is in this discussion.
I am interested because so many online calculators mislead those trying to lose weight. Someone rides 20 miles and they are told they burned 1400 calories when in fact, they might be lucky to have used half that and probably more like 500 calories. So, they guzzle a fruit smoothie or some sugar energy drink. Then, they can't understand why they do not lose weight. That is basically the gist of this thread. But, you derailed it.
/QUOTE]
Funny, I thought you were an old man. Turns out that you're a teen from 4chan. Or could it be that you actually are an old man, just one who acts like a lonely incel teen posting memes and trolling strangers on the internet? Nahhh, that would be just too sad.
Funny, I thought you were an old man. Turns out that you're a teen from 4chan. Or could it be that you actually are an old man, just one who acts like a lonely incel teen posting memes and trolling strangers on the internet? Nahhh, that would be just too sad.
As far as trolling, you are the one enjoying spreading misinformation. What you wrote is just wrong, pure and simple. That you enjoyed the ongoing banter tells me who the troll is in this discussion.
I am interested because so many online calculators mislead those trying to lose weight. Someone rides 20 miles and they are told they burned 1400 calories when in fact, they might be lucky to have used half that and probably more like 500 calories. So, they guzzle a fruit smoothie or some sugar energy drink. Then, they can't understand why they do not lose weight. That is basically the gist of this thread. But, you derailed it.
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Just comparing some power meter data from 2 identical loop rides on consecutive days, but at different average speeds:-
Ride 1: Distance 26 km, Av Speed 23.4 kph, Wind speed 26.1 kph SW, Total Work 440 kJ
Ride 2: Distance 26 km, Av Speed 27.1 kph, Wind speed 20.8 kph SSW, Total Work 557 kJ
So for an increase in average speed of just 3.7 kph, Total Work done increased by over 26%
There were no stops in either ride.
Ride 1: Distance 26 km, Av Speed 23.4 kph, Wind speed 26.1 kph SW, Total Work 440 kJ
Ride 2: Distance 26 km, Av Speed 27.1 kph, Wind speed 20.8 kph SSW, Total Work 557 kJ
So for an increase in average speed of just 3.7 kph, Total Work done increased by over 26%
There were no stops in either ride.
my loops are oddly shaped and i ALWAYS feel like the wind is blowing straight into me on the long westward stretches, and then when i turn around, i’m sheltered by trees and hills and don’t get any benefit lol.
#367
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[QUOTE=GhostRider62;22179291]
I am interested because so many online calculators mislead those trying to lose weight. Someone rides 20 miles and they are told they burned 1400 calories when in fact, they might be lucky to have used half that and probably more like 500 calories. So, they guzzle a fruit smoothie or some sugar energy drink. Then, they can't understand why they do not lose weight. That is basically the gist of this thread. But, you derailed it.
Thanks for writing something in a less confrontational manner. So in the same vein....
Rightly or wrongly, I thought that the OP might be under the misapprehension that by exercising 'harder' to accomplish the same amount of work in a shorter time he was going to burn more calories. My reply, which was the first reply and came before all the technical responses, was merely intended to point out that this wasn't so. I've already acknowledged several times that the point was poorly expressed in my post. Had I appreciated how strong a reaction there would be to quickly dashing out what I thought was a 'fun fact', I would have been much more careful with my wording. Presumably we both know that the reason he burns more calories by cycling faster is because he's done more work to overcome the increased air resistance.
Much of the heat generated later in the thread arose when posters appeared to either deny the validity of my 'faster doesn't necessarily mean more calories' assertion or to disbelieve that that is the point that I had been trying to express in the first place, however clumsily.
Believe it or not, I didn't come into this thread for a fight. All my other interactions on this forum have been very civilised and pleasant. This experience came as a bit of a shock
I am interested because so many online calculators mislead those trying to lose weight. Someone rides 20 miles and they are told they burned 1400 calories when in fact, they might be lucky to have used half that and probably more like 500 calories. So, they guzzle a fruit smoothie or some sugar energy drink. Then, they can't understand why they do not lose weight. That is basically the gist of this thread. But, you derailed it.
Rightly or wrongly, I thought that the OP might be under the misapprehension that by exercising 'harder' to accomplish the same amount of work in a shorter time he was going to burn more calories. My reply, which was the first reply and came before all the technical responses, was merely intended to point out that this wasn't so. I've already acknowledged several times that the point was poorly expressed in my post. Had I appreciated how strong a reaction there would be to quickly dashing out what I thought was a 'fun fact', I would have been much more careful with my wording. Presumably we both know that the reason he burns more calories by cycling faster is because he's done more work to overcome the increased air resistance.
Much of the heat generated later in the thread arose when posters appeared to either deny the validity of my 'faster doesn't necessarily mean more calories' assertion or to disbelieve that that is the point that I had been trying to express in the first place, however clumsily.
Believe it or not, I didn't come into this thread for a fight. All my other interactions on this forum have been very civilised and pleasant. This experience came as a bit of a shock
Last edited by david101; 08-10-21 at 06:23 PM. Reason: had quoted the same post twice
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860 calories in an hour implies an average power of around 240-250 watts. This would take a lot of fitness to achieve. To only go 15 mph on 240-250 watts would mean either a stiff headwind or uphill the whole way.
I would estimate that you needed an average of 100-105 watts for 15 mph and you burned 180-200 calories in half an hour, at the most.
I would estimate that you needed an average of 100-105 watts for 15 mph and you burned 180-200 calories in half an hour, at the most.
Online cyclists seem to be averaging at least 200 watts or more. In real life, the cycle club riders I know are likely in the 120-150 watt range. They can ride 50 miles and 3000 feet of elevation pretty easily, but at a moderate pace.
The 200-250 watt riders are twice as fast on hills and are often averaging over 20 mph on their somewhat flatter rides. There's quite a few of them, but even more of the slower riders. Still, even 100 watts average for an hour is difficult for lots of casual riders -- it takes some practice to hold a steady enough pace -- casual riders often do a small burst of energy, then coast and repeat.
The rule of thumb I've seen and experienced is around 20-25 calories per mile. It's surprising to me how often this works out for me, and adding some climbs doesn't really change the numbers most of the time. I would reach the low 30 cal per mile range with a strong-for-me steadily hard effort. Of course, wind, rider weight, etc, all factor in. But my powermeter just shows the actual power I'm using, which readily converts into fairly accurate calories.
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The rule of thumb I've seen and experienced is around 20-25 calories per mile. It's surprising to me how often this works out for me, and adding some climbs doesn't really change the numbers most of the time. I would reach the low 30 cal per mile range with a strong-for-me steadily hard effort. Of course, wind, rider weight, etc, all factor in. But my powermeter just shows the actual power I'm using, which readily converts into fairly accurate calories.
FWIW, my calories per mile seems to average around 45. 50-100 feet of climbing per mile. 220lb total weight including bike, clothes, water, me. average speed almost always 15mph +/- 1.
Human efficiency is only 24%
Another problem is that humans aren’t perfectly efficient engines. We spend a lot of energy on heat production, balance and other things while riding a bike. In fact, efficiency of cycling humans is around 25%. We burn 5 joules of energy for each joule delivered to the pedals. That means we should divide the measured joules by 0.25 to calculate the actual expenditure. By coincidence, the joule to kcal conversion mentioned above is 0.2389. So, the last two problems cancel each other out, and we can just swap joules for kcal.Last edited by mschwett; 08-10-21 at 08:36 PM.
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that’s really interesting. how much does the wind speed factor? 5.3kph is a decent difference, but was it a loop?
my loops are oddly shaped and i ALWAYS feel like the wind is blowing straight into me on the long westward stretches, and then when i turn around, i’m sheltered by trees and hills and don’t get any benefit lol.
my loops are oddly shaped and i ALWAYS feel like the wind is blowing straight into me on the long westward stretches, and then when i turn around, i’m sheltered by trees and hills and don’t get any benefit lol.
3. Av Speed 30.2 kph, Wind 14.5 kph SE, Total Work 608 kJ
So much less wind than the other rides, but yet more work done at the higher speed.
Av Power vs Av Speed for those 3 rides was:-
1. Power 111W, Speed 23.4 kph
2. Power 162W, Speed 27.1 kph
3. Power 197W, Speed 30.2 kph
Terrain was rolling hills with a few short moderately steep climbs. Notably less windy on ride 3.
Last edited by PeteHski; 08-11-21 at 05:26 AM.