tonybaldwin: tony baldwin (Default)
I need a #physicist and/or a #physician here.
I want to be able to calculate #calories burned in a running #workout .
Now, there are all kinds of "calorie calculators" online, but I don't want to use those. I need to know what math they employ to derive their answers.
But searching online just keeps giving me these "calorie calculators".
No where am I finding a mathematical formula, which is what I was hoping to find.

If I try to work backwards from the answers they give me:
The three factors most commonly asked for are
My #weight: 145 lbs
Time: 30 mins
Activity: #running 10 min/mile
Response: 330 calories

Seems to imply that moving 145 lbs 3 miles burns 330 calories,
thus, 110 calories/mile to move my carcass.
(actuall, I've lost c. 5lbs, and am now down to 140, but just working from past workouts).

I think this gives me 110/145=calories/pound/1mile
This gives me roughly 0.7586 calories/lb/mile

So, if I weighed, theoretically, 160 and ran 5 miles
0.7586X160X5, I burn 606.9 calories?
One of the online calorie calculators gives me 608, so I can't be too far off (-1.1 difference).

So I've come up with (for English measures, lbs., miles).
calsburned=`echo "0.7568 * $weight * $distance" | bc -l`

Because a #calorie is simply a measure of heat or kinetic energy, thus, work,
and, work, as I understand it (high school physics, my friends)
is a matter of moving a certain mass a certain distance.
My understanding is that the speed or time is irrelevant.
It shouldn't matter whether I walk or run.
(although, I'm aware that resistance/friction probably do have an influence).
Moving 145 lbs 1 mile, apparently expends 110 calories.
So why do they ask me my pace or the time in these calculators?
(of course, they didn't ask for distance, but with the time+pace, the math is simple).
Shouldn't they just ask for my weight and the distance?
These calculators seem to imply that if I were running faster or slower, that would make a difference,
but, I'm guessing that's because they don't ask for distance, and are calculating that with the time and pace data, as did I.

I'm looking to incorporate this as a feature in runlog, calculation of calories burned.
Now, since I allow the user to choose what units for distances, of course, I'm also going to have to get the math for calories per kg per km, or something, too (anyone?).

But anyone who knows this shite, does it look like I'm on the right track here?

@Runner #fitness #math


tonybaldwin: tony baldwin (Default)

December 2013

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