HRM calorie burn differences

Good question. I was going to say maybe the F4 may have lost signal since you used the strap that belong to the other watch but you would have had to set it again.

Gosh I don't know. :indifferent:

Maybe it is where you were wearing it. I know with my hrm i'm suppose to wear it on my left arm. It does make a difference because it's closer to the heart, just like when you get your blood pressure taken, left arm for the most accurate read. Which one did you wear on your left arm?

Maybe the next time you do the class you can switch the hrm to the opposite arm and see if it does it again. Otherwise maybe the one that records your fitness level also is the most accurate.

Ok just to confuse things more. I jogged today with my polar FT4 and my Timex Ironman zone train and my run keeper app. I also put my numbers into a few web sites. yes both HRM are set up right and for me Yes the Timex is way wrong in their formula and I have know that since the first time I put it on. ANd no I don't jogg fast, slow and steady. I use to run 5 days a week had some foot problems, now I go once a week on my rest day from P90X, which by the way has really helped my feet and made me a stronger jogger. BLAH BLAH BLAH anyway here's the info
Polar 1:29:22 Time Calories 741 Average HR 154 Max 185 In Zone 1:08:09

Timex 1:29:35 Time Calories 1373 Average HR 153 Max 176 In Zone 1:02:00

Run Keeper gives me this 6.30 miles 13:38 min miles 809 cal

WWW.triathlontraning gives me 922 cal info they wanted age 47, weight 155, Gender F , Average HR, Duration.V02 I Use 35

MFP could only put 5mph Its really 4.25 coldn't fine a way to do that 834 calories burned

Health Status web site (say best calcultor) only asked for age and duration 731 cal

Run the Plant web sites two ways to calculate Weight and distance 638 calories Speed and miles per hour 876 Calories

So what does it all mean? I dont know and either does anyone else! But my general thought we cant get to caught up in the numbers
because the power that be are still trying to figure them out. (side note my timex zone trainer I have always know to 1/2 my calorie numbers but there may be people out there that dont and Timex should be ashamhed)
I wear both straps.

One other thing I thought of - I believe my polar watch (A5) has a fitness test mode. Not entirely sure, but I think I've heard it mentioned that the fitness test is a way of calibrating the watch to yourself. So perhaps it might be worth doing the fitness test on both and then doing the experiment again.

I may ask Polar. I was a sponsored athlete for them several years ago, which is how I ended up with 2 HRMs (the RS200 was free with the sponsorship)

Please follow up with us if you do end up talking to them. The data-obsessed would like to know the answer!

Read this from a very savvy MFP member:

http://www.myfitnesspal.com/blog/Azdak/view/the-real-facts-about-hrms-and-calories-what-you-need-to-know-before-purchasing-an-hrm-or-using-one-21472

He actually has a lot of info about HRMs....in posts and blog form.

Great info. Thanks for the post. I can feel good about trusting my bodymedia over the hrm.

I see it was said in the article. A HRM calorie calculations are just that, calculations of the relation of HR to calories burned. That means the numbers are, gasp, an estimate. It takes much more than a HRM to accurately measure calories burned, that is why when you see studies done in a lab on calorie expenditure they have all that stuff attached to the people working out. It is an ok estimate, and some are more accurate than others, but it like all the stuff including stuff like bodymedia and the like are estimates.