Polar FT4 HRM walking calories seem low?!

sna_fubar
sna_fubar Posts: 3 Member
in Fitness and Exercise
I was hoping you guys/girls could weigh in on the Polar FT4, specifically it's calorie-counting feature. I've searched and read multiple threads, but can't find anything that specifically addresses my question. (FYI I'm a 29 year ol male, 155 lbs, 5ft 10)

Here it is:

When walking, the FT4 calorie counter lags other calculators by >50%. For example, when walking uphill on a treadmill (the type that accepts height/weight input) at a heart rate of 60-70 BPM, my FT4 only logged about 25 calories for every 50 the treadmill showed. Also the treadmill BPM meter was synced to my FT4, showing the same heart rate throughout my workout. When I began jogging (and raising my BPM to be "In The Zone"), the FT4 showed 42 calories for the treadmill's 50. Much closer to what I'm used to seeing.

This morning I did a short but brisk .87 mile walk at 3.4 mph which took my 15 min. The FT4 only reported 30 calories! Doesn't this seem low? These stats usually yield close to 65 calories in MFP.

So my question is, can the FT4 be trusted to count calories accurately at lower BPM levels, particularly when walking with a BPM in the 60s-70s? Or should I stick with the MFP calculator, or maybe use MFP but subtract 25% to be safe, and only use the FT4 when I'm jogging or running?

My usual method is to use MFP calculators for walking/jogging because I've found that they correlate very closely with tons of other calculators online. Now I'm starting to have second thoughts. : /

Thanks in advance!

Replies

  • sfbaumgarten
    sfbaumgarten Posts: 912 Member
    Are you wearing a chest strap?
  • Mokey41
    Mokey41 Posts: 5,769 Member
    If your HRM was off it would be erring on the high side not low. The algorithms are set up for steady state cardio with higher BPM so they tend to exaggerate burn if you're under that level.

    Exercise machines always give exaggerated numbers and the numbers in the MFP database tend to be on the high side for most people compared to a good HRM. I have the FT4 and I have no problem with believing the numbers it gives me.
  • FJDodd
    FJDodd Posts: 140 Member
    If your HRM was off it would be erring on the high side not low. The algorithms are set up for steady state cardio with higher BPM so they tend to exaggerate burn if you're under that level.

    Exercise machines always give exaggerated numbers and the numbers in the MFP database tend to be on the high side for most people compared to a good HRM. I have the FT4 and I have no problem with believing the numbers it gives me.

    ^ this

    HRM is more accurate than the machines, and definitely more accurate than MFP.
  • cwolfman13
    cwolfman13 Posts: 41,865 Member
    are you properly wetting the chest strap? is your HRM dropping the signal during your workout? Also, do you have unusually low RHR? Walking 3.5 MPH with a HR of 60 - 70 BPM would suggest to me that you have a very low resting HR...your HRM isn't going to give you very accurate info if you fall outside of statistical averages...either low or high RHR...if you fall outside of statistical averages, the algorithm is flawed for you.

    60 - 70 BMP is pretty much my RHR range...I'm around 110 - 115 when I'm on a brisk walk and my FT4 has always been fairly accurate (though I do always deduct about 20% or so to account for my BMR calories, etc.
  • SkiMummy
    SkiMummy Posts: 33 Member
    Exercise machines always give exaggerated numbers and the numbers in the MFP database tend to be on the high side for most people compared to a good HRM. I have the FT4 and I have no problem with believing the numbers it gives me.

    It took me a while to accept this, but it's true.
    My Polar FT4 is alarmingly accurate, and the machines are not :-(

    Stick with the reading from the FT4 (even when they are not what you want to hear!).
  • sna_fubar
    sna_fubar Posts: 3 Member
    Hey all, thanks to all for the responses.

    Yes I'm definitely wearing the chest strap properly. Also since I just got the FT4, I've pretty much been looking down at the watch constantly. So I'm pretty sure it's not dropping offline at all.

    Thanks to everyone's confirmations of the FT4's accuracy. This is reassuring. At least if the technology is consistent we can all hone in on what our personal numbers should be. :smile:
  • sna_fubar
    sna_fubar Posts: 3 Member
    I just tested my RHR and it's 53, and according to charts like this one it's definitely below average for someone who's 29 years old, in decent shape and with around 23% body fat. ( http://www.sportsscience.co/sport/good-resting-heart-rate-chart-reference-table/ )

    So if my RHR is actually lower than normal, should I calculate what % deviation I am from the norm and add that into my HMR readings?

    Also you mention making deductions for daily BMR, how did you land on 20%?

    Thanks very much

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