# Training & Nutrition - does cycling really burn that many calories?

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.

InTheRain
03-07-08, 10:43 PM
I just did a calculation based on my weight (229 lbs) that indicated that cycling at 14-16 mph would burn 1374 calories per hour. My ride today was 31 miles at 15.2 mph. I've walked on a treadmill and tried to burn 1000 calories per hour. I'm completely wasted after 2 hours. But 2 hours on the bike at the pace mentioned above and I feel fine. The bicycling calculation is from thedailyplate.com.

UmneyDurak
03-07-08, 10:58 PM
It's waaaaaaay over estimating. On my two hour ride I burn around 1300 calories (if I convert Kj to C) thats with average 18-19mph.

Machka
03-07-08, 11:02 PM
I estimate (roughly based on some calculators, etc. plus a personal calculation of quantity of weight lost vs. calories consumed) that I burn about 500 calories per hour. If you weigh a bit more than me, yours might be around 600 calories per hour. Approximately.

Walking burns about 300-400 calories per hour.

InTheRain
03-07-08, 11:07 PM
what "calorie calculators" are you using to come up with your numbers? I can see that weight would have a significant effect on calories burned when doing a weight bearing exercise such as walking or running, but it doesn't seem as though it would be as significant on the bike (unless you are climbing... that's when I know I'm putting much more effort into my cycling as I watch the light weights fly by me.)

Machka
03-07-08, 11:09 PM
Have a look under the Health and Nutrition section on my Links page. The first three there have calorie counters.

But I also base my calculations on actual experience.

InTheRain
03-07-08, 11:34 PM
I found calculators on 2 of 3 websites from your web page. One said 1099 calories per hour and the other said 976 calories per hour based on my weight and average speed per hour. It still seems high. I trust the calorie calculations on the treadmill. Based on the effort between the treadmill and the bicycle, 600-700 calories per hour seems about right.

Machka
03-07-08, 11:39 PM
If you are aiming to lose weight, base your calculations on your goal weight not your current weight. The numbers will probably be somewhat more accurate, and you won't be thinking, "Oh good, I've burned this many calories so I can eat this amount of food".

BryanW
03-08-08, 05:54 AM
I use a chart in a 20-year-old book, but it agrees with UmneyDurak's ~650 per hour at 18-19 mph. At 15 mph, it gives 400 calories per hour, or 24 per mile. It takes no account of weight, aero, hills, flappiness of clothing etc, but as a basemark it's always seemed accurate.

I wonder how much of the US/UK obesity crisis is caused by people using online calculators that tell them they've spent 1000 calories walking down the road to the pub?

garysol1
03-08-08, 06:05 AM
Why not get a good Heart Rate monitor with a calorie burn function? While they are not 100% accurate they will give you a good idea of the work you have done.

Snuffleupagus
03-08-08, 06:44 AM
At 185-190lbs on a "steady state" training ride averaging ~280 watts per hour, I'll put 900kJ of work into the PowerTap. That is between 800-1000 calories. On easy, easy sub 150 watt recovery rides I'll put out 500ish calories per hour. On an hour long hard effort I'll put out more than 1100 calories.

If you're using the fitday calculators, I've found that over rollers I need to adjust the effort down a notch. For example, a hard two hour ride might net me 1900 calories per the power tap. If I use the 16-19mph cycling option, it's a close reflection of reality. If I use the 20+mph, it over estimates.

Also, please remember that you're an experiment of n=1. If you are consistent you will see results. If you're curious, you could get RMR testing at many higher end gyms, or at a hospital to better calculate your basal metabolic needs, get a polar HRM with the "own cal" feature, and subtract a solid 20% from those readings for cycling, and go from there.

CdCf
03-08-08, 06:52 AM
As a rough guide. 400-600 kcal/hour is about right for the majority, if we're talking regular distance riding. Not TT-like conditions, long intervals or hill repeats...

flip18436572
03-08-08, 07:51 AM
I would say that at my weight of 233 and riding at your pace and keeping a cadence of 90, I would barely burn 400 calories in an hour as my heart rate would never get to anything more than 100-105. It would depend upon the workout and your heart rate. Guessing around 600 max.

CdCf
03-08-08, 09:09 AM
Weight doesn't make much of a difference if you're in a flat area and don't stop/start often. If you ride in a hilly area, weight will make a huge difference.

Machka
03-08-08, 10:23 AM
And even if you're riding in hills, you may work hard going up, but you're not exerting that much energy going down.

I wonder how much of the US/UK obesity crisis is caused by people using online calculators that tell them they've spent 1000 calories walking down the road to the pub?

I wonder too! So many people I've talked to overestimate what they are burning, and underestimate what they are eating.

CdCf
03-08-08, 11:47 AM
And even if you're riding in hills, you may work hard going up, but you're not exerting that much energy going down.

In terms of time, though, time spent going down is typically very short compared to the time spent climbing.

If you climb a 10 % grade for 3 km at 12 km/h, it takes you 15 minutes. Assuming it's safe to do so, you could easily descend the same route in four minutes. So, you spent 19 minutes riding up and down, but 15 out of those 19 were spent at a high level of effort, and only four coasting or gently pedalling. The average speed would be 19 km/h.

Compare that to riding 6 km on a flat road at 19 km/h... :)

UmneyDurak
03-08-08, 07:26 PM
And even if you're riding in hills, you may work hard going up, but you're not exerting that much energy going down.

I wonder how much of the US/UK obesity crisis is caused by people using online calculators that tell them they've spent 1000 calories walking down the road to the pub?

I wonder too! So many people I've talked to overestimate what they are burning, and underestimate what they are eating.

Just curious what is your opinion of power meters values they report. Most display total Kj used during a ride, and I keep hearing different things on how to convert that in to Calories. Some say 1 Kh ~ 1 C, others say it's waay less then that.

CdCf
03-08-08, 07:38 PM
Assuming a 20 % efficiency for the human body when cycling, the total power to crank power ratio is about 4:1, and since the kJ/kcal ratio is also ~4:1, a power meter crank output in kJ could be taken as kcal body output straight off.

dobovedo
03-09-08, 10:49 PM
The online calculators simply don't have enough data and are very broad. For example, some people would have their heartrates maxed to go 15 mph whereas I consider it a Sunday stroll of about 60% effort. As others mentioned, using the light or moderate options on them is at least close, but the 20+ setting assumes you are pretty much going all out on a TT and even then I think it's too high.

There are sooo many factors that come into play on a bike. The type of bike you ride, body position, tires, even air temperature. Then there's terrain and wind. I put your numbers into my CycliStats software at my weight (160) and a 40 degree air temp on a flat course and semi-aero position on a road bike and got 461 calories per hour. Using your stated weight bumps it to 511, about 10% higher. However, using a mountain bike, upright position and a rolling course bumps it all the way up to 909. None of these come close to 1374.

I would suggest getting an HRM if you want a more accurate picture. It can be used on both the bike and the treadmill or for any other exercise.

InTheRain
03-10-08, 12:14 AM
I would suggest getting an HRM if you want a more accurate picture. It can be used on both the bike and the treadmill or for any other exercise.

Thanks for doing the calculations. I have a heart rate monitor that I've used on the treadmill (I love using it there as the incline on the treadmill automatically adjusts to keep your heart rate at the target that you select) but I've never bothered to use it on the bike. Is there a "calculator" that will convert average heart rate to calories?

p2000
03-10-08, 04:11 AM
Why not get a good Heart Rate monitor with a calorie burn function? While they are not 100% accurate they will give you a good idea of the work you have done.

That was what came to mind while reading this thread. I have a Polar F6 that recirds age, weight and heart rate. It also reads calories burned. I usually look at this info, but really have no idea how accurate it really is. But since it calculates target heart rate during the ride, how accurate is it?

Again it's not so much that I rely on that function, but I'd just like to know.

umd
03-10-08, 05:10 PM
I think that the 40 cal per mile estmate is reasonable. Factors intensity in somewhat because if you are going harder, you cover more distance (an burn more cals) in the same time. Of course its still just an estimate and is different for each person.

CdCf
03-10-08, 05:20 PM
I use ~20-25 kcal/km, which is ~30-40 kcal/mile.

dahoss2002
03-11-08, 02:56 AM
I use ~20-25 kcal/km, which is ~30-40 kcal/mile.
I like the 30 - 40 cal per mile formula too. Especially when Im counting calories to replace.

TurboTurtle
03-11-08, 10:51 AM
Using the Work from a power meter and an estimation of your efficiency (I've seen estimates from 19-26%) you can estimate Calories within + 5-15%. An HRM is much worse It simply does not have enough data. Calculating by time or miles in cycling doesn't work because, due to the wind, the effort can double with a small change in speed. - TF

umd
03-11-08, 10:59 AM
Using the Work from a power meter and an estimation of your efficiency (I've seen estimates from 19-26%) you can estimate Calories within + 5-15%. An HRM is much worse It simply does not have enough data. Calculating by time or miles in cycling doesn't work because, due to the wind, the effort can double with a small change in speed. - TF

Yes, but the time/distance estimation is better than nothing, and the HRM is better still. Not perfect, but a reasonable rough guide. I've found that 40 cal/mile usually comes pretty close to what my HRM estimates for typical riding (moderate pace, rollers, a few climbs, but no mountain passes) on longer distances. It usually comes in about 1000 cal for 25 miles. Add more climbing or more wind or more intensity and it goes up. I did a ride last fall that was 100 miles with about 8000 feet of climbing, but a nasty headwind for the last 40 miles (and it was not a loop, so it was not a tailwind for the rest of it, it was mostly protected by a mountain range). That ride came out well over 5000, maybe even close to 6000 for the 100 miles, whereas that ride the previous time I did it was estimated closer to 4000, where I would have expected it to be.

I'll be getting a power meter soon, so I'll be able to test the relationship between the HRM estimation and the power meter's readings.

stonecrd
03-11-08, 11:27 AM
Best estimates are based on power and the best on-line power calculator I've used is http://www.kreuzotter.de/english/espeed.htm. If I throw in data for a ride with no climbing, no wind, 20mph for an hour it says 185 watts = 636 kcal. Now add a 2mph wind and you get 214 watts = 736 kcal. You can play around with this to get a pretty good estimate, better than I get with my HRM.

This calculator takes into account bike weight, position, rider weight, wind, slope etc and assumes 25% efficiency.

yanos
03-11-08, 03:27 PM
^Cool website. Thanks for posting it.

SSP
03-11-08, 04:54 PM
The rule of thumb for cycling is 40 calories per mile.

Snuffleupagus
03-11-08, 07:44 PM
Just curious what is your opinion of power meters values they report. Most display total Kj used during a ride, and I keep hearing different things on how to convert that in to Calories. Some say 1 Kh ~ 1 C, others say it's waay less then that.

Who says way less?

The only thing I've seen indicates way more, as the 1:1 formula assumes a highly efficient cyclist. The guys on the wattage list seem to think that 25% is high for many cyclists, and that many are as low as 20% efficient.

UmneyDurak
03-11-08, 09:29 PM
Who says way less?

The only thing I've seen indicates way more, as the 1:1 formula assumes a highly efficient cyclist. The guys on the wattage list seem to think that 25% is high for many cyclists, and that many are as low as 20% efficient.

I heard that from someone a while back. To be fair I don't think they had a clue what they were talking about.

CdCf
03-12-08, 12:50 AM
Who says way less?

The only thing I've seen indicates way more, as the 1:1 formula assumes a highly efficient cyclist. The guys on the wattage list seem to think that 25% is high for many cyclists, and that many are as low as 20% efficient.

I think you misunderstood. If the kJ reported by the power meter is the average power at the crank, times the total time, then it's only the mechanical power, and the conversion factor to total energy used by the body - assuming a 20 % efficiency - is ~1:1.

Snuffleupagus
03-12-08, 05:11 PM
I think you misunderstood. If the kJ reported by the power meter is the average power at the crank, times the total time, then it's only the mechanical power, and the conversion factor to total energy used by the body - assuming a 20 % efficiency - is ~1:1.

That depends upon whether you're assuming 5:1 or 4:1 which is where the 25% number is derived.

TurboTurtle
03-13-08, 07:10 AM
5:1 or 4:1 what?

The conversion is 1 Kj ~ 0.239 Cal. If you use a 1 Cal for each Kj on the power meter, you are assuming a 23.9% efficiency. I have seen numbers stated in the range of 19-26% for the body's efficiency; usually correlating to 'fitness' (i.e. the more fit, the higher the efficiency). Note that you must first have an accurate power meter before any of this applies.

TF

Roody
03-13-08, 01:39 PM
What's the point of getting a more accurate estimate of calories burned? Do people actually spend a lot of time calculating the number of calories in and out? How ridiculous. The time spent calculating would be better spent riding your bike. The only measurement that makes a real difference is your body weight on the scales.

umd
03-13-08, 02:12 PM
What's the point of getting a more accurate estimate of calories burned? Do people actually spend a lot of time calculating the number of calories in and out? How ridiculous. The time spent calculating would be better spent riding your bike. The only measurement that makes a real difference is your body weight on the scales.

If somebody is trying to lose weight, it makes sense to get an accurate estimate. Especially if they normally have trouble "staying on track". It gives a relatively straigtforward method to ensure that you maintain a caloric deficit.

"The time spent calculating would be better spent riding your bike" is not necessarily true. It is really easy to overeat past the excess calories burned, and exercising even more can just make the post-exercise appetite that much stronger. I rode 20K miles last year, with many weeks were over 400 miles and gained weight.

Roody
03-15-08, 02:58 PM
If somebody is trying to lose weight, it makes sense to get an accurate estimate. Especially if they normally have trouble "staying on track". It gives a relatively straigtforward method to ensure that you maintain a caloric deficit.

"The time spent calculating would be better spent riding your bike" is not necessarily true. It is really easy to overeat past the excess calories burned, and exercising even more can just make the post-exercise appetite that much stronger. I rode 20K miles last year, with many weeks were over 400 miles and gained weight.

Except there is no reliable way to measure caloric expenditure on a daily basis. In fact, there's not even an accurate way to measure caloric intake. All the tables you see have different values, and who actually weighs every gram of food that they eat?

Even the best methods of measurement of either "calories in" or "calories out" would probably have at least 5 % error, and that's within the range of the differences that you're trying to measure.

Weigh yourself every week. If the number goes up, eat less and/or exercise more next week. The scales don't lie, and they're fairly accurate.

I do use the 40 calories/mile as a rough estimate, but that's more to motivate myself than to make realistic plans.

CdCf
03-15-08, 03:36 PM
In fact, there's not even an accurate way to measure caloric intake. All the tables you see have different values, and who actually weighs every gram of food that they eat?

I do. At least for most of the year. Although I round everything to the nearest 5 g.

And I mainly use the nutritional values found on the packaging. You'll be close enough in the end. Better than 5 % error.