Calculating Calories Burned Using Heart Rate Monitors

[mystic]

I caught a thread the other day where someone was asking whether her treadmill or FitDay was correct as far as determining how many calories were burned during her exercise. Betty and Brooke suggested using an HRM to get accurate estimates rather than using the treadmill or FitDay's numbers.

So I went and got myself a Polar HRM which is beyond helpful! Can't believe I never used one before. But here's my question...

I just did a test session to see what FitDay, my treadmill and my HRM say as far as calories burned. Here are the results for a 5 mile walk that took 90 minutes. My pace was about 3.4mph and my heart rate average was 150bpm.

FitDay says 350
Treadmill says 650
HRM says 970

Now I know x-country skiing for 60 minutes can burn like 800 calories so a brisk walk for 90 minutes *could* be 970 but that seems high to me.

For those of you with some experience with HRMs, can you tell me how reasonable that number actually is??

[mystic]

Re: Calculating Calories Burned Using Heart Rate Monitors

Just an additional note, I've been checking all the online calculators that tell you how many calories you burn for various exercises and they're all reporting a number similar to the number my treadmill reports. The inputs for those are only weight and time spent.

So the question really is, does the heart rate really affect the number THAT much?

I'm having a really hard time buying the HRMs number at this point.

[Bluebelt2007]

Re: Calculating Calories Burned Using Heart Rate Monitors

I could be wrong, but what I have been told is no. Heart Rate does play a role, but the chances that you burned 970 calories for a brisk walk is doubtful, considering you bodyweight. My understanding is that your body weight plays a much bigger role in determing how many calories you burn, when exercising. I am not a huge fan of Fitday, but IMO, it seems the most accurate of the numbers you listed.

Just my opinion, and great job exercising. You are doing a tremendous job, no matter how many calories you are burning.

[ValidRouge]

Re: Calculating Calories Burned Using Heart Rate Monitors

My HRM generally shows more calories burned than any chart or online calculator or the treadmills/ellipticals themselves too. But not that much! I'm surprised at that calculation.

I also use the Nike +iPod which is like a pedometer and it's calculations are very close to my HRM.

Saying that, I would trust the HRM and the iPod a little better than the mathematical equation that all online calculators and machines use. Your body is different than my body...so how can those machines predict anything about how many calories you are burning. It's a calculated GUESS that takes nothing about YOUR individuality at all.

At least the iPod/pedometer and HRM looks at SOME aspect of you as an individual and your body's performance as opposed to a chart or a mathematical equation.

Just my opinion, as I truly don't know how exactly the HRM's work. I have a Polar F11 myself, and I know you are supposed to calibrate it every so often according to the instructions so that it gives a better prediction of your target heart rate zones and the amount of calories you may be burning.

You may want to look into calibrating your HRM.

[mystic]

Re: Calculating Calories Burned Using Heart Rate Monitors

Bluebelt thanks for the kudos. There's no way I'm going to risk burning up my lean muscle mass. Fitness is the key to long-term weight management and I'm committed to that.

So this calorie thing... bah. My treadmill has no clue what my weight is so it must be using some average number. FitDay is the odd man out if we're going strictly on what all the calculators are saying. Most are giving me a number about 580 and they're all based solely on weight and duration of exercise. One of them asked for age and sex, but its number was also in that 580 range.

Joy, I'll read more about calibrating the HRM. I haven't done that yet, but I did see in the manual some notes about that. You might be on to something there so thanks for that FYI. Tomorrow is my big cardio day again so I'll do another time test and see what I get after calibration.

On a side note? Have either of you or anyone else reading this tried that Body Bug unit they use on Biggest Loser? Supposedly that gives you an accurate reading of calorie expenditure. However, Mark was quite surprised by his 1 pound loss last night so maybe those bugs aren't all that telling after all - hum... love that show.