HRM Question?

04ward
04ward Posts: 196 Member
in Fitness and Exercise
I read where some think their HRM over calculates their calories burned but does anyone have a problem with it "under" calculating? I have a Polar FT4 and I have to be almost unable to breathe to get it up in the target zone set at 107-140. This morning I did 35 minutes on a Spinner and averaged 23 mph and I'm drenched in sweat and it says I burned 110 calories. I could have done that walking to the mailbox and back. :( I felt like I had a really good workout. The Spinner said I burned 523 which I know is always high. I have my data and stats entered correctly. Anyone else having this problem with their Polar FT4? It happens every day.

Replies

  • r1skbreak3r
    r1skbreak3r Posts: 21 Member
    Check your sensor to make sure it's working properly? The batteries could need changing, or it could be faulty. I had a problem with mine where it would randomly read my heart rate at 0 and then jump to 190 every few minutes! I got a new strap (which is a better design anyway) and it's worked perfectly ever since.
  • 04ward
    04ward Posts: 196 Member
    I've only had it for a month and it reads my heart rate but it just doesn't seem accurate. I guess I need to put my Blood Pressure Monitor wrist cuff at the same time that reads heart rate and compare the two. It just seems like I'm really working hard but can never get my heart rate up where it needs to be. Thanks for replying!
  • 04ward
    04ward Posts: 196 Member
    May have just realized what my answer is..........I'm on blood pressure meds and that can affect heart rate. How does anyone else find this affects their target heart rate? http://www.mayoclinic.com/health/beta-blockers/AN01224
  • TinaBaily
    TinaBaily Posts: 792 Member
    I have a new Polar FT4 and just started to use it this week. Since it takes in the stats such as sex, height and weight, the calories burned were disappointingly lower than what the machines at my gym had been telling me. However, that helps explain, in part, why my loss stalled and I've been slowly gaining. In an hour or more workout, I'm actually burning 115 to 169 calories LESS than what I had been thinking, on a daily basis. That adds up!

    Since you are on medication that affects your heart rate, you may want to discuss with your doctor whether your efforts are effective, or if you should trust what your HRM says. I would imagine that you may be burning more than the HRM states simply due to your extreme efforts, but it may also take trial and error with your food intake to see whether you can lose, or if you're losing too quickly. It must be frustrating to try so hard to get your heart rate up, only to have it piddle along like you're resting. Best of luck to you!
  • 04ward
    04ward Posts: 196 Member
    I'm definitely not losing FAST.......hardly at all which is frustrating. I started logging March 6 and was doing 500 calories under what my Fitbit says I burned for the day which was about 20% under but I'm not losing at all. I've played around losing and gaining the same 4 pounds. This week I started trying to burn at least 400-500 calories a day then eat 500 under making me eat at my BMR of 1550 but under TDEE by 800-1000. Hopefully I will see some results. I'm staying pretty close within my macros. Surely something will happen soon! I have a doctor appt next Friday so I'll have to talk to her about it. I just want to get under that 190 mark and STAY under it then start losing from there.
  • rassha01
    rassha01 Posts: 534 Member
    Beta blockers? I was on them and had an issue getting my heart rate above 130. Got BP under control and no longer take them, can easily get into the 160-170s now.

    (Edit) I burn around 800-900 calories per hour running at a 8.5 m/min pace.
  • SpringFever19
    SpringFever19 Posts: 180 Member
    Yes BP meds can definitely affect this. However, make sure you are cleaning your strap regularly and disconnecting the link after every use to save battery.
  • Azdak
    Azdak Posts: 8,281 Member
    Beta blockers lower your heart rate, but they do not substantially lower the calories you burn. They will mess up the HRM calorie numbers, but those are often just play numbers anyhow.

    The calories one burns with exercise are based on the actual workload or intensity level of the exercise or the movement, i.e. on one's oxygen uptake.

    When taking a beta blocker, the oxygen uptake for a given workload remains mostly the same--however it is now associated with a lower heart rate. In other words if you were working at an intensity of 10 METs before at a heart rate of 150, if you do the same workout, you are still working at 10 METs--it's just that now that effort might elicit a heart rate of 115.

    The HRM doesn't know that--it just interprets the lower heart rate as meaning you aren't working as hard.

    Beta blockers can have a small effect on resting metabolism and VO2max. Wt loss can slow while taking them, but people should still be able to lose.
  • 04ward
    04ward Posts: 196 Member
    Beta blockers lower your heart rate, but they do not substantially lower the calories you burn. They will mess up the HRM calorie numbers, but those are often just play numbers anyhow.

    The calories one burns with exercise are based on the actual workload or intensity level of the exercise or the movement, i.e. on one's oxygen uptake.

    When taking a beta blocker, the oxygen uptake for a given workload remains mostly the same--however it is now associated with a lower heart rate. In other words if you were working at an intensity of 10 METs before at a heart rate of 150, if you do the same workout, you are still working at 10 METs--it's just that now that effort might elicit a heart rate of 115.

    The HRM doesn't know that--it just interprets the lower heart rate as meaning you aren't working as hard.

    Beta blockers can have a small effect on resting metabolism and VO2max. Wt loss can slow while taking them, but people should still be able to lose.

    Thank you for the info! I definitely feel the workouts but it sure doesn't register and then I'm not sure how to put it down when I log. I'm frustrated with not losing when I feel I'm doing everything right. Can I ask you one more question. I was taking my calorie burn that my Fitbit showed and eating 500 under that and had no results. This week I started eating at just my BMR which is 1541. My average daily burn according to Fitbit is 2350 which puts me at about an 800 deficit. How do you figure how much to eat to consistently lose?
  • MrsWells1983
    MrsWells1983 Posts: 160
    I have an FT4 and no problems here. I definitely trust it more than gym equipment and MFP due to being able to enter user stats etc. Of course it's not going to be accurate, but it will be damn closer than guessing!

    Not sure how you would work out cals burned if your BP meds are affecting your HR. Good luck!

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