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TOPIC: Does raised heartbeat=more calories burnt??

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May 9, 2012 10:31 AM
Because I have been on steroids (inhaler and tablets now) due to having a chest infection and they make my heart race. At the moment my hr is over 120 bpm and I'm lying under a duvet feeling like rubbish.

So am I burning more calories?!!

Doctor knows this is happening and is ok with it for now because the only other option is not breathing at all :(

Was just wondering???!
May 9, 2012 10:38 AM
that's how heart rate monitors are used to calculate exercise calories. If it's pumping more it's doing more work which requires energy.
May 9, 2012 10:42 AM
But is it really doing more?! It's beating more because of the tablets but I'm not doing anything...
May 9, 2012 10:52 AM
Well, your heart WILL be using more energy ofc, so yes, I suppose your body would require more calories during that time....but it's not like you're moving all of your muscles and working out (as the energy is also used to fuel them). So you'll be burning a bit more as a base rate.
May 9, 2012 10:56 AM
It takes energy to beat the heart, so you will burn more calories. As has been stated, heart rate monitors work by monitoring the heart beat. However, a lot more than that goes into the calories burned calculation behind the scenes. Your heart will be sped up, but the rest of your body will not. The standard calculations done by heart rate monitors will therefore be off.

Long story short, you're burning more calories. But not a substantial enough amount to matter.
May 9, 2012 11:10 AM
I think about this a lot. I have tachycardia too (fast heart rate) my heart rate is usually around 130-140 and goes bananas when I exercise. Since it is impossible to find the formula that heart rate monitors use to calculate calories burned it's hard to tell what is really going on. I tend to assume that the formula is based around a normal response to exercise and not hearts going bonkers with no provocation like ours do. I'm pretty sure it's not how fast the heart beats that determines how many calories that are burned I think other factors go into it. If heart rate is all that matters I'm pretty sure I would have died of starvation long ago :) If you get a chance ask your doctor (I always forget to) and let me know what you find.
May 9, 2012 2:36 PM
Like others have said, the *only* thing a HRM can measure accurately is the rate of your heart.

In order to directly measure how many calories you are burning, you literally have to measure how much heat your body is giving off. It can be done in laboratory, but its not very practical.

The next best thing would be to measure how much oxygen you consume and how much CO2 you give off. This is certainly do-able at a specialized doctors office, but still not very practical.

The idea behind a HRM is that if you are burning up calories through exercise, your muscle cells need extra oxygen. In order to get more oxygen to your cells, your heart has to pump faster. So, by measuring heart rate, maybe it should be sorta possible to guess how many calories you are burning.

But your heart has to work harder to get oxygen to muscles in your legs than, say, your arms. And it has to work harder if you are vertical compared to horizontal. And as your fitness improves, your heart grows larger so it moves more oxygen per beat. And your arteries/veins can get bigger (or smaller) depending on if you do more aerobic/endurance exercise or more strength training. And on and on. Plus, as others have mentioned, tons of other things can make your heart speed up or slow down for reasons unrelated to exercise.

So there is no way to "convert" from heart rate to calories burned, because its really a big sloppy mess. In the special case where a perfectly average person is doing aerobic exercise under perfectly average conditions, then its possible to make a guess that isn't too far off. Because the HRM can never know if thats the case, its up to the user to decide if all these conditions apply, and even then to take the calculated number with a grain of chocolate. Oops, I meant salt !
Edited by jjs22 On May 9, 2012 2:38 PM


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