Caloric burn based on HR

[jumpie]

Hi guys,
I posted this question a month or so ago but didn't get any responses - I'm wondering if anyone might know of a site or a way of calculating calories burned durring an activity based on one's heart rate.

Reason being - these little guides, like fitday.com and others, just base it on body weight and speed (assuming you are running) This doesn't make sense as there could be a 180 lbs person running at 6.5 min / mile which takes all their ability and another 180 lbs person that runs all the time and therefore it is very easy. Obviously, they can't be both burning the same amount of calories in the same time frame. Being able to get a better estimate of calories burned would help me in establishing calories needed in a day.

Thanks.

[Lost Dog]

For running, you should go by weight and distance, not time or heart rate.

http://www.runnersworld.com/article/...0-1069,00.html

In fact, you can reverse the calculations on fitday to see that they are about the same as the ones on this calculator.

To do what you propose, you would need a heart rate monitor that had calorie count built in, since the rate is constantly changing.

That being said, this method would not be accurate for many activities that are not purely aerobic activities. Weight training comes to mind. The calories burned by muscle repair in the days after lifting are far more than those burned during the lifting itself.

There's really no way to get to a truly accurate number. You can get close enough to your maintance level, then add or subtract a decent amount to lose or gain weight. After that, you just have to track your progress and adjust accordingly.

[jumpie]

OK, but I'm still unsure as to why this is? A highly trained endurance runner burns as many calories if he runs the same distance as an out of shape person? (assuming they are both the same weight and run the same speed?) That just doesn't seem to make sense. Aren't calories burnt a mesure of engery expended, and therefore shouldn't the more fit person expend less calories doing the same activity as an unfit person? I'm not saying you're wrong, I guess I just don't quite see how this works. More info would be appreciated. Thanks for the reply.

[bryanc]

Um...if an 'out of shape' person was the same weight (and presumably stature, but that's not really relevant) and could run the same speed and distance as a trained endurance runner, would said 'out of shape' person be 'out of shape'?

The short answer to your question, though, is no, since calorie expenditures are activity dependent. I can get my heart rate up pretty high on an arm crank ergometer, but I don't burn the same number of calories as the same heart rate on a rowing ergometer.

[jumpie]

OK, on the first point - lets say it was only for 15 minutes - an out of shape person could run the same speed as a trained individual, but if I read you right, you're saying that they would still burn the same amount of calories. Still need convincing - I guess I'm just missing something simple here.

On the second point, I can see how HR would have to be relative to the activity - ie. one couldn't say that the same HR on the stationary bike would result in the same caloric burn as the same HR running. Good point.