Calories

markcroninbsc

Lumen wrote: »

The 80 calories is BMR. I don't understand how that relates to cycling efficiency and calorie estimation.

and like i said that was only if you wanted to get silly about it... which you obviously are

blue chuzzle

markcroninbsc wrote: »

i dont have any documentation around that 30% number i was just saying that calculating calorie from power measured from a power meter could be upto 30% inaccurate. i was saying everything put together could amount to 30% of a difference in calories burned.

saying something could be something with no figures to back it up at all is meaningless.

the sun could be mostly cold. most elephants could be microscopic. getting annoyed at the internet could be a waste of time

what you should say(if you have to say anything about it) is "my guess would be that its not very accurate" and leave it at that.

you have no facts or figures to start with so ending with one is crazy.

markcroninbsc

blue chuzzle wrote: »

saying something could be something with no figures to back it up at all is meaningless.

the sun could be mostly cold. most elephants could be microscopic. getting annoyed at the internet could be a waste of time

what you should say(if you have to say anything about it) is "my guess would be that its not very accurate" and leave it at that.

you have no facts or figures to start with so ending with one is crazy.

thats just stupid!!

i was saying that the calories calculated from a power meter are from the power that passes thru the power meter and that there are alot of other places where power is wasted before it gets to the power meter. If you could back it up with an exact figure then there wouldnt be an inaccuracy you could just add that on at the end.

The figure i was talking about was a sum of all power lost before it gets to the power meter, and the 2% inaccuracy of the power meter itself.

Muscle efficiency varies between people by about 10% or so. if you've got an inefficient riding/pedaling style you could be burning an extra 5-10% calories rocking the sholders, pulling on the handle bars, not pushing properly on the pedals etc(that figure might be high im not sure on that one). Altitude and temperature will only effect things by a couple of percent too. if you want the exact figures for every variable then google it. i did kind of imply that i didnt know the exact figures the 30% is just a guess and that at the most extreme, using power is probably reasonably accurate for the average joe, but its still going to be only accurate to 5 or 10% which i think is alot. The thing about using power is that its more consistent than the heart rate calculations.

The only really accurate way to test the amount of calories being burned is in the lab monitoring the amount of oxygen being consumed.

Khannie

So it turns out my cycle in is worth about 800 odd calories. I'm delighted. I got offered a loan of a power meter and a garmin by a kind boardsie (thank you sir) which I jumped at. Averaged 205W for just over 70 minutes. Taking average efficiency of 25% that works out at 860 odd calories, give or take. Joules to calories roughly cancels out the human inefficiency element so the simplified calories formula becomes:

(Average power in Watts x Seconds) / 1000

Good to know anyway.