Polar FT4 - how does it work out calories?

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Darmanin
Darmanin Posts: 75 Member
in Fitness and Exercise
I got a Polar FT4 for mothers day just under 2 weeks ago and have been using it for exercise and my morning walks. I am not sure how it all works.

When I first set it up it showed my resting heart rate as 76

But when I go to start exercise I'm always standing having got off the train, or out of the car to the gym etc... so my resting heart rate is always a lot higher 90-105

So I had thought that the calories MFP calculated for each exercise was over stated, but so far it has been understating it for me.

Eg...
This morning 48 min walk ... 46 mins of that 'in the zone' (124-162) .... average heart rate 139, with 412 calories burnt.

Last night I did 10 mins on the stationary bike and then 5 mins of these polymetric exercises in a magazine I was reading, then level 1 of 30DS .... 47 mins ... 39 in the zone, average heart rate 143 ... with 425 calories burnt

Then at the gym sunday night, which was 30 mins on the treadmill (1min run, 2 min walk etc...) weights various, 10 mins x-trainer (level 6, 600 mtrs), 10 mins bike (level 6, 4.5km). Total time 87 mins, 65 in the zone ... 142 average heart rate, with 766 calories burnt. .... I started the watch when I was standing on the treadmill, and stopped it when I was on the floor stretching.


The calories burnt just seem really high. Is it because my 'resting' heart rate just before I start is already quite high and it's giving a false reading because of it? Or does it use the 76 from my original setting as the baseline to calculate the calories.

i know all this probably doesn't really matter all that much, I just want to understand how it works. And to make sure I'm using it correctly.

thanx

Replies

  • Melo1966
    Melo1966 Posts: 881 Member
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    I am not sure if starting heart rate matters but those numbers do not sound too high. You are really working hard part of the time.
  • omgoozles
    omgoozles Posts: 23 Member
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    When you set it up did you enter your height, weight, etc? Usually this is needed to calibrate the formula used. But I find MFPs calculations are sometimes spot on, sometimes off by huge margins. When I use a HR monitor for Aerobic exercise it's generally pretty accurate..but when I'm doing weight lifting, it's off by a lot...on the low side.
  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
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    Azdak explained it pretty well in his blog. He also explains how to make sure it is set up properly.

    Did you take your resting heart rate first thing in the morning?

    http://www.myfitnesspal.com/blog/Azdak?month=201003

    Also check out how to test for accuracy
    http://www.myfitnesspal.com/topics/show/774337-how-to-test-hrm-for-how-accurate-calorie-burn-is
  • innocenceportrayed
    innocenceportrayed Posts: 569 Member
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    I have the same one or I think it is. Mine has a chest strap and a pink watch, I don't know if it's the FT4 but it's Polar.

    Anyway.

    Your resting heart rate is literally how often your heart beats when you're sitting still doing nothing, just relaxed watching TV or something. Once you get up and start moving, it will rise naturally.

    I don't wear my strap and watch when I'm doing nothing. My resting heart rate is about 70 and my max is about 188. When you're "in the zone" you're in the "fat burning zone" and if you keep your heart rate there, the more calories you're going to burn. When I'm on the treadmill and I'm doing interval running, I go from about 135-180 up and down in that range for at least 20 minutes and I burn about 400 depending on how many run intervals I do, but when I do a less strenuous activity like tonight I did the elliptical (because all the treadmills were taken and it was pouring rain out) my heart rate only got up to 165 and after 20 minutes I'd only burned 180 calories.

    If you accurately entered your weight and age and you wear the strap, most likely it's calculating correctly. I do not trust MFP numbers over my HRM numbers.
  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
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    When you set it up did you enter your height, weight, etc? Usually this is needed to calibrate the formula used. But I find MFPs calculations are sometimes spot on, sometimes off by huge margins. When I use a HR monitor for Aerobic exercise it's generally pretty accurate..but when I'm doing weight lifting, it's off by a lot...on the low side.

    That's because HRM calorie estimates are based (with exception of a few higher end models) on formulas for steady state aerobic exercise. Weight lifting, for the most part, is not aerobic and the increased HR is not related in the same way so it is not accurate.
  • Darmanin
    Darmanin Posts: 75 Member
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    Thank you for the info. Yes I did enter my weight and height. And I updated my weight yesterday as I had lost 2 kgs since I got the HRM and will continue that each time my weight goes down.

    Thank you for that, so maybe it is right. I am always huffing and puffing and sweating at the end of it but I figured it's just because I'm still 30kgs overweight and not fit.
  • patrickmathews
    patrickmathews Posts: 41
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    There is a formula used for calories burned. I don't know the exact formula but the factors are height, weight, age and hear rate (not resting heart rate). As long as you have your height weight and age in the settings, you are getting as accurate a count of calories burned as you will get with a Polar FT4. I have a Polar monitor as well, I think it may be an FT4 (I forget the exact model). I've been using it for quite a while now. Before the FT4, I had a much older one. They all do the same thing, the only real difference in the models are (in my opinion) bells and whistles - like how many workouts it stores, connectivity to an iphone etc..


    I think these monitors are great at giving you an objective view of your workout. Having said that, I'm sure there are certain use cases where the accuracy of the calorie count may be suspect. There is always some next level exercise gadget that claims to be better but I think as long as you are using a heart rate monitor that has it's sensors close to your hears (not on the wrist), it is about as good as your going to get without going to a cardiologist for a stress test.


    Resting heart rate is typically calculated upon waking up in the morning before you get out of bed. As soon as you start moving around, you raise your heart rate to something other than "resting".
  • Nicolee_2014
    Nicolee_2014 Posts: 1,572 Member
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    Your resting heart rate is basically when you are doing nothing, so if you were on the train etc. that is doing something (standing, listening to the other people around you maybe getting flustered?) so it would be a higher read even though you aren't technically doing exercise.

    My resting heart rate was 45 or 50, so I feel like I have to work harder to get results. With the Polar FT60 when you go to train it actually asks if you want to start the training at your current heart rate or go by your resting heart rate. Does the FT4?

    I'd say if you've lost 2kgs you are definitely doing something right! :flowerforyou:
  • ElizabethWillNotFail
    ElizabethWillNotFail Posts: 35 Member
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