Dumb questions about heart rate monitors and calories burned

hemlock2010

1) If you exercise at the same average heart rate, do you burn the same number of calories no matter what form of exercise you're doing?

So for example, would biking for an hour at a heart rate of 140 bpm burn the same number of calories as an hour on an elliptical trainer at 140 bpm?

2) If you want to use heart rate during exercise to track ifitness, how would this work?

Thanks!

Holly

1FitMomof4Girls

Good question, I am interested in this too!

Sherri71

I am interested too, since I have a slightly lower heart rate than average. Had an EKG and it showed my heart rate at rest was 69. 70+ is normal.

luv2ash

Yes, me too. I use a heart rate monitor, but my calories burned seem to be the same no matter what I do, and now that you mention it, this is probably why. So why when we go into exercise database on MFP, we get all kinds of numbers,most of which for me are way higher than what my HRM tells me.

techcommdood

From what I've found, no. There are way too many factors involved in caloric burn. If you lift weights, your body continues to burn calories even when you're back at rest (muscles are magic). A heart rate monitor can help give you a rough idea of what you're burning, but it's not exact. That said, because I'm not having luck equating METs to activities by defined exertion levels (and therefore don't know if chosen activities' calorie burn figures are accurate given my actual activity), I'm getting a heart monitor to at least help me determine the proper MET level for my activities performed.

bedienung

Well, there is this paper called "Prediction of energy expenditure from heart rate monitoring during submaximal exercise" which suggests, that it doesn't matter what exercise you do. Have a look at http://www.triathlontrainingblog.com/calculators/calories-burned-calculator-based-on-average-heart-rate/ for a calculator using the formula given in that paper.

However, they didn't really look into this (sometimes I really hate physicians for their ignorance), but the heart rate monitors I've seen all show similar results, maybe +/- 5%.

hemlock2010

Thanks!

TrainingWithTonya

Unfortunately, it isn't as easy as that. Physics says that to move an object X distance at Y rate, you have Z energy burned but my heart rate to consume Z energy may be vastly different then your heart rate to consume Z energy. The more fit you are the lower your heart rate, generally. If there isn't a setting for fitness level, that can lead to the HRM giving a lower calorie burn for the person with the lower heart rate regardless of whether they are doing the same amount of work. However, there are times when your heart rate can be artificially elevated, too, such as after consuming caffeine, certain medications, while under stress, in pain, etc., which will give a higher calorie burn from a heart rate monitor even for just sitting still.

Different activities require different amounts of energy based on how you are moving, how much mass you are moving, etc. Also, how much effort you put into it will have an effect on calorie needs. I use a METs compendium to determine an estimate of calorie needs. It is based on an average calorie burn for different activities in a lab setting. It's not the most accurate either, but since it averages the high achievers who give their all with exercise and the half-assers who just go through the motions to determine a MET level for the activities, it's a pretty decent average of what a specific activity uses, if the activity has been studied in a lab setting. You can check out the METs compendium at http://prevention.sph.sc.edu/tools/docs/documents_compendium.pdf to see the MET level of what you are doing to see if you are getting something similar in calorie readings. Multiply the MET level by your weight in kilograms to get Calories per hour. You may find that you are burning similar calories for different activities or you are burning vastly different calories. Like for Weight Training. Because the heart rate goes up while lifting and then back down on the rest periods, you may or may not get an accurate calorie burn from the average heart rate and it doesn't account for the EPOC curve after exercise at all. But if you get two vastly different calorie estimates, then you can take the average of the two and get your own estimate. After all, none of the ways we estimate calories (expended or consumed) are 100% accurate. Close counts here.