Heart Rate Monitor Accuracy?

PatchFan
PatchFan Posts: 19 Member
in Fitness and Exercise
Hey everyone,

I know this sort of question has been asked before, but I've not found a very satisfying answer. Anyway, for the first time today, I wore a heart rate monitor (Polar FT4) while running on the Life Fitness elliptical trainer at the gym. The number of calories burned that each machine provided me were vastly different. Now, I'll say that ordinarily, my intuition would be to trust the heart rate monitor. However, the number just seems too high (and good) to be true.

In 30 minutes (with an average heart rate of 185) of running, the heart rate monitor told me that I burned 540 calories, while the elliptical trainer gave something along the lines of 300. I put my height, weight, sex, and age into the heart rate monitor, and I'm aware that they're not supposed to be totally accurate (I've read they can be off in the ballpark of 13-20%), but even so, the discrepancy is just too huge. Any ideas?

Replies

  • FatFreeFrolicking
    FatFreeFrolicking Posts: 4,252 Member
    Heart rate monitors are way more accurate than what the machines give you for 'calories burned.'
  • MrsJane05
    MrsJane05 Posts: 44 Member
    HRM will always be closer to the REAL burn, than what the machine says.
  • Chieflrg
    Chieflrg Posts: 9,097 Member
    I believe the PolarFT4 you have to subtract your living calories as it doesn't do that automatically.
  • MelodyandBarbells
    MelodyandBarbells Posts: 7,724 Member
    Basically did a 200 lb man burn 1080 calories per hour running. I'd say it's possible your hr runs a bit high. Were you running outside? If so you may want to give an app like MapMyFitness a shot and see what kind of numbers you get.

    You may have seen this formula for net running calories burned

    .63 X distance (miles) X body weight (lbs)
  • PatchFan
    PatchFan Posts: 19 Member
    I believe the PolarFT4 you have to subtract your living calories as it doesn't do that automatically.

    Are you sure about that? And if so, how do I do that?
    I'd say it's possible your hr runs a bit high. Were you running outside? If so you may want to give an app like MapMyFitness a shot and see what kind of numbers you get.

    You may have seen this formula for net running calories burned

    .63 X distance (miles) X body weight (lbs

    I was running on an elliptical trainer, not outside. My understanding is that it's easier to run on elliptical trainers than it is outside, so I can't imagine that formula would be the same.
  • brianpperkins
    brianpperkins Posts: 6,124 Member
    Did your HRM think you were actually running or on an elliptical? The difference in the two activities results in a different burn for identical duration, exertion, and HR data.

    Lower end HRMs lack the ability to differentiate between events which leads to problems. Many people advocate using HRMs for activities where the scientific backend doesn't exist to generate accurate formulas so they use generic situations that don't match. The simple mechanical difference between walking and running results in about twice the net calories burned running versus walking ... without doing the homework to understand that, it is easy to overestimate. Almost all low end HRMs report gross, not net, calories burned meaning you have to calculate your non exercise calories burned for the period in question then subtract that from the total given by the device.

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