HeartRate Monitor skepticism

AlannaPie
AlannaPie Posts: 349 Member
edited September 20 in Fitness and Exercise
I got the Polar F6 from eBay and I used it during my workout today. I was on the treadmill and it said I burn 250 doing that - seemed accurate enough. Then I took a boxing class. I would say that this was particularly intensive because there wasn't much down time, but it said I burn another 750 calories! Is this possible?!?! I don't see how it could be. I think I would be a lot thinner. Of course I want to see what I burn in other classes, but can anyone think of things that might make this number larger than it should be? I have mitral valve prolapse which causes me to have a slightly irregular heartbeat. Could this be screwing the monitor up?

Replies

  • savvystephy
    savvystephy Posts: 4,151 Member
    How long was the boxing class?
  • AlannaPie
    AlannaPie Posts: 349 Member
    1 hour. There was jumping rope, circuit training, and boxing drills
  • Azdak
    Azdak Posts: 8,281 Member
    I got the Polar F6 from eBay and I used it during my workout today. I was on the treadmill and it said I burn 250 doing that - seemed accurate enough. Then I took a boxing class. I would say that this was particularly intensive because there wasn't much down time, but it said I burn another 750 calories! Is this possible?!?! I don't see how it could be. I think I would be a lot thinner. Of course I want to see what I burn in other classes, but can anyone think of things that might make this number larger than it should be? I have mitral valve prolapse which causes me to have a slightly irregular heartbeat. Could this be screwing the monitor up?

    Since the calorie count is pegged to your heart rate, anything that affects heart rate will result in an over or understated reading--if the heart rate change is not related to changes in exercise intensity. Some examples can be physical reasons--cardiovascular drift, dehydration, excessive temperature, illness, overtraining, arrhythmia--others can be mechanical--improper contact with the chest strap, interference from another device.

    One thing to check when reviewing your workouts is average heart rate and maximum heart rate (I'm pretty sure the F6 shows both). Your average heart rate for the boxing class is almost certainly significantly higher than it was on the treadmill.
  • savvystephy
    savvystephy Posts: 4,151 Member
    I think it is very possible for you to have burned 750 calories. I walk 4.0 miles in 1 hour (which is not nearly as active as the boxing) and burn 500 - 600 calories. So, if your heart rate is high, you burn more calories. I haven't had any problems with my Polar F6. :wink: Besides, I hear boxing is quite the work out.
  • lotusfromthemud
    lotusfromthemud Posts: 5,335 Member
    It's entirely possible that your calorie burn is that high. In a hardcore workout, I easily torch through 800 calories.

    That being said, Polar HRMs don't subtract you RMR calories, so you need to manually subtract them when you enter in your exercise calories here.

    They're what I call "sitting on the sofa" calories. . .what you would have burned in the same hour even if you weren't boxing. Regrettably, exercising doesn't add time to our day.:flowerforyou:
  • Peschuntz
    Peschuntz Posts: 270 Member
    Yes, it is possible to burn that amount of calories if the intensity and time are put into an activity. But it is also possible to eat those calories burned in one fell swoop, e.g. a piece of cake, a large plate of spaghetti or a few drinks. It is unlikely that mitral valve prolapse would interfere with the operation of your Polar. In fact, on the Polar web site, a few people have told stories whereby their HRMs picked up irregularities in cardiac rhythm which may have led to heart attacks if gone untreated.

    I own a Polar and believe it to be a highly reliable instrument. My recommendation is keep track of your activity over the next week as well as everything you consume. If you don't find your answer after monitoring your activities and calorie consumption then I would speak to your physician as there may be some other obstacle operating such as undiagnosed thyroid disease. Good luck.
  • AlannaPie
    AlannaPie Posts: 349 Member
    When I was jogging it averaged at 170 bpm.
    During boxing it was 174 over the course of 1 hour
  • twilight1542
    twilight1542 Posts: 403
    When I was jogging it averaged at 170 bpm.
    During boxing it was 174 over the course of 1 hour

    WOW! Your heart rate sounds very high--assuming that was your average & not maximum. Polar will have average & maximum and shows your cardio zone. I would recommend, based on advice I've gotten on MFP, to try to keep your heart rate w/in your cardio zone.
  • Peschuntz
    Peschuntz Posts: 270 Member
    Your heart rate sounds too high, particularly for someone who has mitral valve prolapse. That heart rate sounds too high for almost anyone. You may be causing yourself harm by pushing yourself like that. If I were you I would have a discussion with my physician about working out safely, and stay within your appropriate cardiac zone. The point of using a HRM is to alert you if you are working too hard or not hard enough. You need to pay attention to what it is trying to tell you or you may be causing untold damage to yourself.
  • savvystephy
    savvystephy Posts: 4,151 Member
    Her heart rate is not necessarily high for her age. She is 26. When you do the target heart rate equation (220 - 26) her maximum is 194. 90% of her maximum is 174.6, so she is working in her hardcore training zone. This is I suppose, so long as her heart rate stayed around 174 or 170, not much higher or below it.

    I don't know what it would have to do with the mitral valve prolapse, so I suppose you could talk to a doctor about that.
  • AlannaPie
    AlannaPie Posts: 349 Member
    It never went over 181 I believe so it was pretty consistant. The valve gives me a sinus arythmia, which means that my pulse speed up when I inhale and decreases when I exhale. But I think when I'm exercising my breathes are shorter so it's not as obvious an issue. I don't know! I need more research
  • silencer
    silencer Posts: 3
    :happy: I have a F7 and it is a blast. The HR follows the HR on the Cybex Elliptical I warm up on. My only complaint is I have not been able to sync it to the on line web site program.
  • BrendaLee
    BrendaLee Posts: 4,463 Member
    If your heart rate is staying relatively steady, as it sounds like it is, then it would seem the mitral valve prolapse probably isn't affecting your heart rate during your workouts, so I'd say the calorie burn sounds pretty reasonable.
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