My New Polar FT4: Not Sure if it's Accurate

shiningpotential
shiningpotential Posts: 50
in Health and Weight Loss
Hi! I just received my new Polar FT4 HRM today in the mail from eBay. I set the weight, height, DOB, and gender. I then put on the chest strap and watch, and started the "training". I proceeded to brush my teeth, put in my contacts, and took a leisurely walk down the street with my girls. My heart rate barely stayed in the zone. I just wanted to get a feel for using this thing. In an hour and five minutes, my HRM is saying I burned 315 calories. Keep in mind that I barely exerted myself. As for my personal stats (and this is REALLY hard to share, but relevant to the topic), I am a 31-year-old female who weighs 189 and is 5'4". To me, it seems that 315 calories in an hour is kind of a high read. I mean, I go to the gym, and on the elliptical machines, or Stair Masters, or bikes, it always seems to take forever to get that many calories burned. Is my Polar HRM accurate, or is the gym equipment more accurate?

Replies

  • Ready2Rock206
    Ready2Rock206 Posts: 9,487 Member
    Since none of that involves a steady elevated heart rate which is what HRMs track, no it wouldn't be at all accurate.
  • seekingjoyandfitness
    seekingjoyandfitness Posts: 48
    Hi! I just received my new Polar FT4 HRM today in the mail from eBay. I set the weight, height, DOB, and gender. I then put on the chest strap and watch, and started the "training". I proceeded to brush my teeth, put in my contacts, and took a leisurely walk down the street with my girls. My heart rate barely stayed in the zone. I just wanted to get a feel for using this thing. In an hour and five minutes, my HRM is saying I burned 315 calories. Keep in mind that I barely exerted myself. As for my personal stats (and this is REALLY hard to share, but relevant to the topic), I am a 31-year-old female who weighs 189 and is 5'4". To me, it seems that 315 calories in an hour is kind of a high read. I mean, I go to the gym, and on the elliptical machines, or Stair Masters, or bikes, it always seems to take forever to get that many calories burned. Is my Polar HRM accurate, or is the gym equipment more accurate?

    Do you remember what numbers there were? What was your range of heart rate?
  • shiningpotential
    shiningpotential Posts: 50
    It generally stayed between 100 and 125, I think, once I started walking.
  • BusyRaeNOTBusty
    BusyRaeNOTBusty Posts: 7,166 Member
    Heart rate monitors track heart rate. Your heart rate is accurate.

    However, the equation they use to convert heart rate to calories burned is ONLY VALID DURING CARDIO EXERCISE, not while brushing your teeth, lifting weights, etc.
  • StaciMarie1974
    StaciMarie1974 Posts: 4,138 Member
    Your HRM is not valid as a tool to measure burn for normal, everyday activity which requires limited movement or constant starting, stopping.

    But based on your stats, your BMR is about 68 calories per hour. Meaning if you did nothing but lay on the couch for an hour snoring - you'd burn at least 68 calories just for your body's regular functions. So to be on your feet, casual walking & movement its reasonable to think you'd burn at least 2 calories per minute. And perhaps 2.5-3 while on the leisurely walk. Not based on anything scientific, just the assumption that when you add in additional activity you burn more calories.
  • Barbellarella_
    Barbellarella_ Posts: 454 Member
    It generally stayed between 100 and 125, I think, once I started walking.

    So, 5 minutes or so to brush your teeth and get on the road would mean you walked about an hour, correct? That seems pretty accurate for an hour walk at your height and weight to me.

    You could always plug the walk into MFPs database to see what it says you burned. Just for comparisons sake.
  • shiningpotential
    shiningpotential Posts: 50
    It generally stayed between 100 and 125, I think, once I started walking.

    So, 5 minutes or so to brush your teeth and get on the road would mean you walked about an hour, correct? That seems pretty accurate for an hour walk at your height and weight to me.

    You could always plug the walk into MFPs database to see what it says you burned. Just for comparisons sake.

    MFP says I burned 257 calories in one hour of leisurely walking. Since that is a smaller number than my HRM told me, I erred on the side of caution and used that as my figure on my log today.
  • shiningpotential
    shiningpotential Posts: 50
    Your HRM is not valid as a tool to measure burn for normal, everyday activity which requires limited movement or constant starting, stopping.

    But based on your stats, your BMR is about 68 calories per hour. Meaning if you did nothing but lay on the couch for an hour snoring - you'd burn at least 68 calories just for your body's regular functions. So to be on your feet, casual walking & movement its reasonable to think you'd burn at least 2 calories per minute. And perhaps 2.5-3 while on the leisurely walk. Not based on anything scientific, just the assumption that when you add in additional activity you burn more calories.
    That makes sense. Thanks!
  • mom2pandc
    mom2pandc Posts: 14 Member
    I have the same watch. When you're done with your workout, you can scroll through to see how many total minutes you exercised and how many of those were in your target range. If most of the minutes aren't in the target range, I wouldn't rely on it being very accurate. In which case it would log a lower number like you did. If most of the minutes are in range though, I think it's pretty accurate.
  • JoeCampbell85
    JoeCampbell85 Posts: 140
    I use a heart rate monitor during every workout. I do HIIT and HRM are notoriously bad at monitoring HIIT. I don't stress it though. I log what it says and I see how my weight loss is doing in the coming weeks. If I didn't lose the weight I wanted I adjust my calorie consumption. I keep the HRM as a steady (even if inaccurate) source of calorie expenditure and adjust something that is far easier to track somewhat reliably and that's calories in. I recommend the same for anyone with HRM monitors, especially the lower models.
  • heybales
    heybales Posts: 18,842 Member
    http://www.myfitnesspal.com/topics/show/774337-how-to-test-hrm-for-how-accurate-calorie-burn-is

    Because even the nicer Polar even with lab tested stats on it (which you have neither the stats nor the place to put them on the cheaper Polar) is still off.

    http://www.myfitnesspal.com/topics/show/459580-polar-hrm-calorie-burn-estimate-accuracy-study

    But you can use it to get your avgHR for a session, and then have your own personal calorie burn formula.

    http://www.myfitnesspal.com/blog/heybales/view/getting-your-personalized-calorie-burn-formula-663625
  • shiningpotential
    shiningpotential Posts: 50
    Thank you all for the input. It's really helping me decide how much to depend on this thing, and how to stay on track regardless.

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