Ok, so this is sort of a theoretical question... I don't usually pay a huge amount of attention to calories, but I'm still very puzzled.
The background: I am a member of a hot yoga/ circuit training studio that has some very intense classes. The other day the studio made a post on their facebook page that one of their students, a woman who weighs about 100 lbs, burned over 800 calories in one of their classes, and they posted a photo of the heart rate monitor she was wearing, which read 827 cals. The class is an hour long.
I am also a roughly 100 lb female about the same age as the woman in question, and have never seen calorie burn on my HRM that high after 1 hour, even with pretty intense workouts. Just out of curiosity, I googled heart-rate calorie counters to try to see what it would take for a 100 lb female roughly my age to burn 827 calories in an hour.
I found one, and put in some educated guesses for the parameters and started calculating calorie burn. I found that it wasn't quite as hard as I expected (though it still stretches my credulity a little) to get a calorie burn at least in the right ballpark, but as I was playing around I noticed something that seemed off. As I increased the weight parameter, the calorie burn went down, rather than up. There was no height parameter, so it didn't seem like the calculator was adjusting for fitness or BMI based on the weight. So the way it was calculating, it was telling me that a woman the same age and fitness level as me but a foot taller would burn fewer calories while working at the same intensity. This doesn't make any sense to me at all.
My reasoning: calories are a unit of heat energy that can be converted to Joules, the standard unit of measure for work in physics. Joules are equal to kg·m2/s2 (can't do superscripts here, but that would be meters squared and seconds squared) so that all other things being equal, as weight increases, work increases. Work = energy expended = calorie burn.
I know that fitness level can impact efficiency and therefore precise calorie burn between individuals of the same weight, or the same individual at different weights, etc. but for approximate calculations those things would be assumed to be constant, no? I found a couple more calculators, and they are all behaving the same way. Some have more data fields than others, but none ask for both height and weight. The really odd thing is that if I calculate calorie burn for men, the burn increases with weight as I would expect; it's only for women that it seems to be backwards. Am I missing something? It doesn't seem like all of these calculators could be wrong.
Here are the ones I've tried:
Heart Rate Based Calorie Burn Calculator
Calories Burned By Heart Rate | Calories Calculator
Heart Rate Based Calorie Burn Calculator for Unknown VO2max
http://www.braydenwm.com/calburn.htm
The background: I am a member of a hot yoga/ circuit training studio that has some very intense classes. The other day the studio made a post on their facebook page that one of their students, a woman who weighs about 100 lbs, burned over 800 calories in one of their classes, and they posted a photo of the heart rate monitor she was wearing, which read 827 cals. The class is an hour long.
I am also a roughly 100 lb female about the same age as the woman in question, and have never seen calorie burn on my HRM that high after 1 hour, even with pretty intense workouts. Just out of curiosity, I googled heart-rate calorie counters to try to see what it would take for a 100 lb female roughly my age to burn 827 calories in an hour.
I found one, and put in some educated guesses for the parameters and started calculating calorie burn. I found that it wasn't quite as hard as I expected (though it still stretches my credulity a little) to get a calorie burn at least in the right ballpark, but as I was playing around I noticed something that seemed off. As I increased the weight parameter, the calorie burn went down, rather than up. There was no height parameter, so it didn't seem like the calculator was adjusting for fitness or BMI based on the weight. So the way it was calculating, it was telling me that a woman the same age and fitness level as me but a foot taller would burn fewer calories while working at the same intensity. This doesn't make any sense to me at all.
My reasoning: calories are a unit of heat energy that can be converted to Joules, the standard unit of measure for work in physics. Joules are equal to kg·m2/s2 (can't do superscripts here, but that would be meters squared and seconds squared) so that all other things being equal, as weight increases, work increases. Work = energy expended = calorie burn.
I know that fitness level can impact efficiency and therefore precise calorie burn between individuals of the same weight, or the same individual at different weights, etc. but for approximate calculations those things would be assumed to be constant, no? I found a couple more calculators, and they are all behaving the same way. Some have more data fields than others, but none ask for both height and weight. The really odd thing is that if I calculate calorie burn for men, the burn increases with weight as I would expect; it's only for women that it seems to be backwards. Am I missing something? It doesn't seem like all of these calculators could be wrong.
Here are the ones I've tried:
Heart Rate Based Calorie Burn Calculator
Calories Burned By Heart Rate | Calories Calculator
Heart Rate Based Calorie Burn Calculator for Unknown VO2max
http://www.braydenwm.com/calburn.htm
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