Calorie Burn

ExigeR

I will apologise in advance as I'm sure this has been done before.

Which one of the examples below would you say is closest to the amount that have been burned off during a 3 hour turbo work out.

This is the trainer road workout i did.

https://www.trainerroad.com/cycling/rid ... tarmigan-2

As you can see TR says 2415 cals
Wahoo app says 2568 cals
One of these avg HR-cals burned sites on the net say 2643 cals
And the Garmin said 1898 cals

Im 42 and weigh 142 pounds, avg HR was 151bpm

This has been bugging me for a while now, i always use the Garmin as a log but its always so much lower.

crikey

3 hour turbo work out.

You've destroyed waaaay more brain cells than calories.
3 hours? I'd rather walk for 3 hours; at least you can go somewhere!

Alex_Simmons/RST

Every W of average power at the pedals ~= 3.8 Cal per hour within +/-10%, and probably within ~+/-5%

If you know your actual average power (measured, not guessed) then your energy metabolised in Cal (kcal) will be:

Average power x number of hours x 3.8

e.g. 150W x 3.00 hours x 3.8 = 1710 Cal +/- ~100 Cal.

Unless you know your actual power output, then you really won't know.

Conversely, 2600 Cal / 3.8 / 3.0 hours = 228 watts +/- ~15W

That's 3.5W/kg for 3 hours on an indoor trainer. I've no idea if for you that's plausible or not. It would be a doddle for some, it would crush others and for many, it's impossible.

ExigeR

Thanks for that.

I only have the avg power reading from the Kickr which says NP was 229w (watt/kg 3.46) I guess these figures aren't as accurate as a power meter but its all i have to go by at the moment.

Are Garmins really that far out then?

ExigeR

crikey wrote:

3 hour turbo work out.

You've destroyed waaaay more brain cells than calories.
3 hours? I'd rather walk for 3 hours; at least you can go somewhere!

I'd like to say i had plenty to destroy but thats probably not true

diy

Given your weight - I'm gonna go with the garmin. though the avg HR is pretty good. But if its any help you've probably got another few 100 from the EPOC, if you finished hard.

ExigeR

Another strange thing the Garmin seems to do is 20mins into this workout my avg HR was about 138 and doing 10 cals per min and the last 15mins my HR was the same give or take a few bpm and i was averaging 2 cals per min :?

Its not just this workout it seems to be the same on all of the ones i do.

Alex_Simmons/RST

Energy estimates from anything other than a good power meter are likely to be in the light comic relief category. Even with a power meter the uncertainty with your gross efficiency means the accurately known mechanical energy from the power meter is still going to provide an energy metabolised estimate with a margin of error.

diy

I thought they used better methods now? Claims suggest 10%+-
http://www.dcrainmaker.com/2010/11/how- ... armin.html

10 cals / min is what I go on for a moderate to hard indoor workout. I then use what I call "minutes ahead" as my guide on performance - i.e. how many minutes I finished under the 1 hour, after hitting 600 (or 450 for a 45 min workout) I always get more on the road for some reason. Its not a bad measure given that you get well behind to start with the warm-up. The longer the ride the easier it is to get ahead.

BrandonA

Does it really matter?

Unless you are on a calorie controlled diet and you know exactly how many calories you are consuming and how many you are burning for all aspects of your live the difference between your upper and lower values really isn't that much and not worth worrying about.

bahzob

Alex_Simmons/RST wrote:

Energy estimates from anything other than a good power meter are likely to be in the light comic relief category. Even with a power meter the uncertainty with your gross efficiency means the accurately known mechanical energy from the power meter is still going to provide an energy metabolised estimate with a margin of error.

Seconded. I have been using a power meter and trying to keep weight under control for 8 years now. Even knowing the actual KJ per ride only provides a rough pointer in terms of calories burned, even less so in terms of weight change.

I think its handy to have a feel if you are burning 200, 500 or 1000 calories per hour in terms of diet planning and nutrition for long events but anything more exact than that will be just a guess.

bobmcstuff

According to DCRainmaker some of the Garmins (800 and 500) use the Firstbeat algorithm for calculating calorie burn which is supposedly about as accurate as you can get without doing tests.

In terms of whether it matters, it really depends on what you're trying to do with the information. You have to take it with a hefty pinch of salt regardless. Personally when I was losing weight I did take it into account (and had a lot of success with it combined with calorie counting food - I found it motivational because I work best with lots of data, obviously that won't be true for everyone), but now I don't really look at it except out of interest.