blanqui

I used the workout calculator on mapmyride.com for a century I did today and it says I burned over 5000 calories. That seems a bit high doesn't it??
The ride was nice but not much climbing at all and I sure as hell didn't hammer it--17.5 mph average.
https://www.mapmyride.com/ride/united...e/734279517756

merlinextraligh

Unless you weigh 3 bills, it had a ton of climbing, or you did it sub 4 hours solo, yes.

botto 

just a tad.

Grasschopper

Ok so what is a good calculator to use? I know the figure my Garmin's kick out is over stated...but lets say my ride yesterday:

58.7 miles, 2 big (as big as they get in my area) climbs accounting for the majority of 3600' of rise and I rode for just shy of 4 hours (yea yea its slow...@ 210 lbs I crawl up the 6-8% avg grades of these climbs). So how many calories did I really burn...for the record the Garmin said something over 4k...I figured closer to 3k but pretty much pulled that number out of my *****.

merlinextraligh

I'd guess between 2500-3000. I'm about your size. For me an hour at endurance pace is about 500-600 calories. (per the powertap). I've got to be drilling it to do 900 calories an hour, pretty much TT pace. And while you may have been burning in 900-1000 calories an hour while climbing, you were burning essentially nothing on the descents.

My saturday ride was 65 miles, about a third of the vetical of yours, and 3 hours in length. Powertap gave me a little over 2000 for that.

Grasschopper

One of the calorie counting programes just kicked out 3600. For the record the decents are short and sweet...neither was longer than 5 min so of that 4 hours only 10 min of it was bombing those decents. So split it I guess and say about 3k.

Had a wonderful lunch ride today...14.22 miles in an hour...1500' of vertical. Man it's steep up here.

Road Bike Guy

I think the Powertap is pretty accurate in calculating calories. I did a century on Saturday that had 5500 feet of climbing (rolling hills) and averaged 18.7. When I downloaded the file it came up with 3500 calories or so. My weight is 163. My friend's Polar said she burned 4800 calories on the same ride. The only problem is that she is only 130 pounds and she averaged 18. I think mine was a little more accurate.

6Stringer

A lot of web sites and magazines claim that a 150lb rider burns 750 calories in an hour at 15mph. I weigh 155 and my Garmin seems to use 750/hr rule. So, is 750 calories an hour @ 15mph not accurate? My Garmin GPS would say the OPs calculated value is fairly accurate.

hyunelan2

My HRM (also known for being horribly inaccurate) says I'm between 600-650 calories (age 28, 190lbs) for my nightly 15-mile loop with the wife. It takes almost exactly an hour.

kudude

750 calories at 15 mph if you're going up a 5% grade. On the flats w/o wind ---c'mon now.

umd

I usually estimate about 4000 calories for a century, unless it is particularly windy or mountainous.

MONGO!

All calorie counters are wildly inaccurate.

mp123

The number the Powertap shows is how many kilojoules of work you've done through the hub. In order to calculate the number of calories you need to divide that number by 4.185

BUT, here's where it gets interesting. Your body is only 20-30% efficient so now you need to multiply the answer from above by some factor (3-5 roughly) to figure out how many calories you've actually burned. In other words most of the calories you've burned while riding were not measured by the Powertap and instead went up as heat.

As a shortcut people tend to cancel out the dividing by 4.185 and multiplying by roughly 4 and just treat the Powertap's kilojoules figure as how many calories they've burned. Obviously if you use a figure other than 4 you'll get a different number of calories burned.

merlinextraligh

^ Given that it's not feasible to measure your actuall efficiency, washing the 4.185 against the efficiency factor is a pretty good working assumption. If anything it likely slightly understates the calorie burn.

So while there is this element of a fudge factor in using a Power Meter for calorie burn, it's more accurate than HRM's and on line calculators, and about as accurate as you're going to get outside a lab.

MIN 

600-700 Cal/hr road riding for an average sized guy.

umd

Actually, if you get your VO2 tested, they should be able to measure how many calories you are actually using by the amount of CO2 produced by O2 consumed, and then you can use that to determine your conversion factor. Anyway, I had that done and it was pretty cool, but I don't have a power meter to use for reference. It was pretty spot on to what I usually was estimating based on HR.

mp123

Agreed.

But consider that a Powertap indicated 1200 kilojoules might really represent 955 (30%) - 1433 (20%) calories which is a pretty big spread.

It's easiest to just use an efficiency factor of 4.185 which corresponds to roughly 25% efficiency and wash the whole thing out, that's what I do

RoadToNowhere

You mean like THIS?:


or THIS? :



Beth

RoadToNowhere

Nice route blanqui - think I'll save this one for another day. I do some riding out in that area, and really don't know the roads on that side of the river very well.

As to the original question, my reference point is a bit different. . . female, 120 lbs. . . a century in that area at 17.5 puts me at just over 2500 calories. FWIW.

Beth

Booger

Seems like most are estimating 25 calories/mile? If you average 18mph (a decent clip for many of us), that's only 450 cal/hr. Seems a little on the low side.

I've always used 40 cal/mile as a very rough estimate, but there are just too many variables to know for sure.

umd

I use 40 cal/mile as a starting point and adjust for conditions. I don't really do anything with the numbers, so the accuracy is not important

kudude

Why is it that serious training everyone uses time, but for casual rides it's distance?

A hilly century in much, much more work than a pancake flat 150miles.

Even if they take the same amount of time the calorie burn shouldn't be the same.

NYJayhawk

For a while I used two different caluclators...one was consistently high, and one was consistently low. I averaged them together (bad data + bad data / 2 = refined bad data).

Now my polar calculates it for me, and it's averages are close to my aforementioned formula.

There are tons of variables to consider that make these guesses pretty tough to make accurately. I'm 6'6" and 240lbs, so it takes a lot more calories just for me to exist, much less push through the air or ride a bike up a hill. So while a 150 pound cyclist might average 500 calories in an hour, I might reasonably expect to burn 750 over the same ride.

The best thing to do is just use the calorie estimates as a relative gauge. So if you have two different rides but the calories work out the same, you can reasonably assume that they were "close" in how much effort was involved (long and slow vs. fast and hard).

z3n

my garmin gives me an average of 2200 per 50k....seems high to me

dark13star

I take the calorie results from my Garmin and divide them by 4.16, multiply by Pi, and then discard them

Seriously, Garmin claims I burn 4,000 calories on my medium climbing loop which is about 33 miles with 5,200' of climbing. I generally have two bottles of HEED, a Hammer Bar, and maybe a gel shot on that ride. I would weigh a lot less than 155, if the Garmin were accurate.

I usually just assume that I have burned enough calories to justify a good dinner and maybe a couple of beers.