's Forum Archives - General

Archive Home >> General(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 )

Calorie burning question(31 posts)

Calorie burning questiongregario
May 30, 2002 5:56 PM
I'm trying to find out how many Calories I would burn given a certain body weight and speed. Of course, the answer would be a gross estimate. Most charts I've seen only have cycling at, for example, 12 mph or so, which is ridiculous. Does anyone know of any sources? I would really like to know, at 195#, how many Calories per hour I would burn at an average 19mph. I know there would be many variables, but I want a ballpark figure.
Well... (long)Sherpa23
May 30, 2002 7:39 PM
I have done a lot of this sort of testing for studies (I was the subject, not doctor) and the only way to really measure calories burned is by measuring work, not spedd and not heart rate. I use an SRM for training and most racing for certain reasons but one of the "side" benefits is that I get total work calculations and therefore, calorie calculations. I have often compared the results to speed and heart rate and it is VERY difficult to say that a certain number of miles per hour is so many calories. Depending on cadence and gearing, the calories burned can vary significantly. By the way, body weight would only matter when climbing as there is little added work required for bigger riders when riding on flat roads. Having said all of that, based on my data 12-15 mph is VERY ROUGHLY about 325-475 calories per hour.
May 31, 2002 4:00 AM
yeah,i know I'm looking for a number that can have many variables attached to it. Basically, I want to lose 12-15 pounds and want to know how many hours I would have to ride to burn off that Girl Scout cookie that is tempting me. When I think about it in those terms it really gives me something to think about before I stick that cookie in my mouth. I did a little looking around the net last night before I posed my question and all I found was a chart for a woman riding 12mph with a body weight of 127# or so.
From my filesSherpa23
May 31, 2002 6:25 AM
I didn't read the last bit of your message and did not see the 19 mph average part. Since that is a pretty normal average for a solo ride, looked in my files for something as close to that as I could find and here is the result from a recovery ride I did on Tuesday:

Time: 3:05 Kms:112 Avg HR: 122 Total calories: 1903

I hope that helps.
More info...Sherpa23
May 31, 2002 9:06 AM
Some people who know my email sent me some messages regarding my last post so here is more info. This is not important for the calories burned but for those of you who feel it is, and want it in addition to that file info that I posted, I weigh 158 lbs, stand 5'9.5", and I am 26 years old. That ride was a 2nd workout of the day and it was after a hard physical therapy effort so my HR was about 5-6 beats higher than normal. That has no relevance to calories burned but I an giving you all the info because you asked. And to the 2 requests for power information, I'm sorry but my power data is something that I feel is akin to proprietary information and I don't give those numbers out. Hope this helps you to find your calories burned per ride and feel free to email me any more questions and I will do the best that I can to answer them.
Yet more info...Sherpa23
May 31, 2002 9:32 AM
Okay, got some more emails so here is more info. Yes, it was a solo ride on pretty flat terrain, mostly 41x19 gearing but a little 41x17 (<15 minutes), I was counting the physical therapy as the first workout of the day and that's what I had to recover from. Yes, the SRM is properly calibrated and I recalibrate at the beginning of each ride. I hope this answers your questions and no worries, I am glad to help.
re: Calorie burning questionelviento
May 30, 2002 8:33 PM
Hey, I am just a few pounds lighter than you are and average about 19-20mph, so we should have similar numbers. My numbers are around 600 calories per hour.

Those charts with 12mph speeds are typically useless because they assume new bikers on non racing bikes and with non aero positions. I know because according to those charts I'd be using 1200-1300 calories per hour which can't be right. If you are a reasonably experienced rider with aero position and a good bike, you can easily ride at 19mph using the same energy an inexperienced rider needs to go 12mph.
Forget speed ....pmf1
May 31, 2002 4:28 AM
Its about 40 calories per mile, no matter what speed you go.

600/hour for 19-20 mph is too low. Does it seem reasonable that you only burn 3000 on a century?
Yes, that would seem about right...Wayne
May 31, 2002 4:34 AM
How many calories do you think you're burning on a century (of course this would vary depending on how hard the course is and how hard your riding)? Added to roughly the 2000 or so calories you burn just existing for the day, that's a 5000 calorie day.
where do you get that figure?gregario
May 31, 2002 4:51 AM
40 Calories/mi?

I tend to be a "one speed" biker. Every ride for me is a time trial when not riding in a group, which I basically no longer do. I find it very difficult to "take it easy". So, I guess that a given Calorie count per mile makes sense since if you're riding hard and covering more miles you would just burn them faster, and a slow ride would take longer but the amount of effort would burn the same Calories.
It may make sense assuming it's a flat course, butWayne
May 31, 2002 5:23 AM
I assure you I can go downhill for a mile and burn far less than 40 calories, or climb for a mile and burn a good bit more than 40 calories. I think this whole discussion is largely an exercise in futility. Unless you can measure work the estimate you decide to use is so inexact as to be kind of pointless. Use 40 cal per mile or 600 calories per hour or whatever, what's it matter? You have no way of evaluating the relative merit of one vs. the other, everyone here is just speculating.
Hey, I just want a general ideagregario
May 31, 2002 5:49 AM
Look, I just want a ballpark figure to think about next time I have that extra piece of pizza. I'm not looking, nor did I expect, a precise answer. In my original question I stated there are many variables.
You have no way of evaluating the relative merit of one vs. theelviento
May 31, 2002 8:28 AM
I am pretty sure the 40ca/mile theory is without merit.
Scientifically, because air resistence is not directly proportional to speed, so if you double your speed, you cut the time in half, but you typically need 4 times or more energy to do that, therefore riding the same course at different speeds CERTAINLY take different amounts of energy. If you try a 30 miler at 23-24mph, and then try one at 15mph, you would know what I am talking about.
If you think your 30 mile Sunday cruise at 15mph burns the same amount of engery as Lance's record beating time trial over the same distance, you are just kidding yourself.

I have given this a lot of thought and done tons of research, and pretty sure 600 calories is a reasonably good number, given a certain weight, riding style, speed, and assuming roughly flat course. I'd extremely surprised if his actual number is below 500 or above 700. Again, I am not saying 600ca/hr is good for all cyclists at all speeds. In fact at 15mph, I need only 280-350 calories per hour.
Here you go, the answer..Wayne
May 31, 2002 8:37 AM
from the info people have given lets go with this;
calories per hour:
easy effort 500
mod/hard aerobic effort 650
all out/LT effort 800
That should be good for any guestimates and it's based on effort so that it doesn't matter how fast or far your going!
Everybody agree?
Here you go, the answer..elviento
May 31, 2002 9:09 AM
I think the easy effort can get lower (well it's hard to define easy anyway) and all out effort can get higher (I once read that TT-ing at the top level like attempting the hour record can use 1300-1400ca/hr).
O.K. I'll modify myWayne
May 31, 2002 9:24 AM
guestimates, let's go with;
easy effort 400 cal/hour
mod/hard aerobic effort 700 cal/hour
max/LT effort 1000 cal/hour
Can we agree on that? Of course I'm being sarcastic, are we any closer to the answer than when the thread started? Is the question answerable? For gregario's sake he just needs to pick a number he's comfortable with. Based on what I've read here, if I were him I'd go with 600 cal/hour that way I'd be sure to underestimate what I need to eat to replace what I burned off.
All right, Mr. Know-it-All, here's a referencepmf1
May 31, 2002 8:39 AM
They say 780 calories per hour for a 170 lb man racing. That's in the range of 35-40 calories per hour.
Thanks for the nickname.elviento
May 31, 2002 9:02 AM
The number you quoted sounds about right. All I am saying is you can't leave out speed, because going at an easy pace uses very little energy. If you drop 5mph from 20 to 15, you can spare almost half the energy.

Besides, if they use 780 calories in racing condition, 600 doesn't sound too low for my 19mph training rides, does it?
Your logic is faultypmf1
May 31, 2002 9:43 AM
Take it to the limit and assume you are sitting on your bike going zero miles per hour. How many calories per mile do you burn then? An infinite amount.

If you look on that site at different speeds, it shows that you actually burn more calories per mile the slower you travel.

If I ride for an hour at 20 mph I'm sure I burn less calories per mile than if I ride for two hours at 10 mph. Why? Because I'm doing something for two hours rather than one. Even sitting still, you burn calories. So I disagree with you that you burn more calories per unit distance the slower you go. Its true per unit time, but not per unit distance.

I think I'm right here. I'm not even tempted to dispell the wannabe economists above.
I think that site is misleading...Wayne
May 31, 2002 10:22 AM
1st of all you can't count the calories you're burning just by existing for 2 hours rather than 1 because that introduces a variable that is irrelevant to whether the effort itself of going 2 hours at 10 mph burns more calories than going 1 hour at 20 mph. And I really doubt the site took that into account. Follow me here, I'm not sure I'm 100% correct but I think I am. For arguements sake lets say it takes 100 watts to go 10 mph, so for two hours you get 200 watts total. But to double your speed and go 20 mph doesn't take twice as much wattage because wind drag doesn't increase linearly but to some power between 3 and 4. So you can't just put out 200 watts over an hour and go 20 miles, you need to put out 250 or 300 watts or some bigger number to overcome the nonlinear increase in drag. So for those 20 miles you've expended more calories covering them in 1 hour than if you did it twice as slow and covered them in 2. Now if you found a 20 mile climb and went slow enough that you eliminated wind drag maybe it's true that you would burn the same amount of calories to cover it in 1hr vs. 2hr.
You're forgetting somethingpmf1
May 31, 2002 10:56 AM
You burn calories just staying alive.

You're thinking of calories per unit time, not distance. Sure, If I go 20 mph for an hour, I burn probably twice as many calories than if I go 10 mph for an hour. However, I don't burn as many calories riding for ONE hour at 20 mph than I do riding TWO hours at 10 mph. Distance covered is the same, calories burned is not.

If I rode 20 mph for ONE hour and then sat for ONE hour, I'd probably burn more calories than riding 10 mph for TWO hours.

Like I said, take the extreme case of going 0 mph. You burn infinite calories per unit distance. As speed decreases, calories per mile increases. The reason for this is that there is some constant amount of calories burned just to keep breathing. Calories expended just living are fairly significant. I don't think they are cancelled out by your wind drag argument (which I find hard to believe increases by 3-4 times from 10 mph to 20 mph).

At any rate, I don't think 30-40 calories per mile is an unreasonable response to the guy's question.
We get your pointelviento
May 31, 2002 12:12 PM
"Sure, If I go 20 mph for an hour, I burn probably twice as many calories than if I go 10 mph for an hour."

And this is exactly where you are wrong. As Wayne pointed out, the increase in drag is non linear, therefore going 20mph for one hour uses more than twice the energy of going 10mph for one hour. Probably 3-4 times. Since you need to go 10mph for two hours to cover the distance, then the engery is doubled. But doublling it cann't offset the 3-4 times difference due to the increase in effort. This has been scientifically proven.

The other thing is we should not bring the calories for existence into the query because those calories will be spent whether you exercise or not. We should only focus on the calories used by exercising. Afterall, it's what Greg was asking.
All right, Mr. Know-it-All, here's a referenceWayne
May 31, 2002 9:08 AM
I don't know if I'm Mr. Know-it-All or not but again, ANY reference for any calories/mile or calories/time is fraught with so many assumptions that it's not going to be very accurate even most of the time. It might hit it sometimes for some people under some conditions, it might not. That's all I was saying, just go with my guestimates. Christ, I said 800 calories per hour at a hard/LT pace (is that racing speed?) which just about hits their 780, and I based my estimates on nothing other than the spotty numbers some people provided here. To go back to the point I made above, if I descend a 10 mile mountain pass, and then I climb a 10 mile pass will I have burned the same number of calories over each of those 10 miles? For that matter, if I climb the 10 miles at my 160 lbs and my 300 lbs buddy climbs those 10 miles will we have expended the same calories/mile?
May 31, 2002 9:38 AM
I had no idea my question would lead to such a controversy. I'm just looking for a ballpark number to hang my helmet on. I wanted to know how much exercise is being "cancelled out" by that bagel I have after I bike, especially if I want to lose 12 pounds. Yeah, i know there are variables like wind resistance, weight, grade, etc.

I thought that the question I posed a couple weeks ago about the number of young yet bald pros having anything to do with steriod abuse would be more controversial.
Its a Friday afternoonpmf1
May 31, 2002 9:47 AM
Kind of funny how tangential things get into big arguments here. So many experts. Hey, you did get some ballpark numbers though, right? Yeah, they're averages and don't take all the little details (as was astutely pointed out), but that's all you were looking for anyway.

Lotta miles in a bagel.

I like to point out all the pros that have children when people tell me cycling makes you sterile and I need a saddle with a hole in the middle.
From a friendpmf1
May 31, 2002 5:26 AM
I have no scientific formula or reference. This guy I know lost a lot of weight cycling. He said he calculated how many calories per mile were expended and factored it into his diet. He weighs about 180 now. He's a real exacting nerd type. I'm sure he has a reference and carefully thought out calculation. I tend to believe him.
May 31, 2002 5:51 AM
That will give me something to think about when I get back from an evening ride and am looking for something to eat.
Oatmeal ...pmf1
May 31, 2002 6:24 AM
You can eat lots of it, its low in calories and high in fiber. It fills you up and can be flavor enhanced with pieces of fruit or some brown sugar. Easy to make and cheap too. Get the Old Fashioned kind, not the instant stuff.

I try (but don't always succeed) to eat some everyday.
Oatmeal ...gregario
May 31, 2002 11:12 AM
i eat it several times a week, even more after I found out my cholesterol was 276.
Oatmeal ...pmf1
May 31, 2002 11:19 AM
Did it lower your cholesterol?
Oatmeal ...gregario
May 31, 2002 1:03 PM
yeah, it dropped it about 20 points to 254 but now I've been on Zocor since the last test too. I've been on the drug for about 40 days and as of last week it's now at 215 and should drop further.