My first-date with a HR monitor

Springerrr
Springerrr Posts: 44 Member
edited December 3 in Fitness and Exercise
I went out and got a Polar FT4 (off Ebay! $12!). I tried it for the first time last night. I was fascinated by the heart rate and now see easily why I do not run very far before having to walk! The session lasted 55 min, four miles. I ran the first couple of miles, then alternatively ran to 160BPM, then walked to 135BPM, then ran again, etc! This HR-guided run/walk was a very cool way to go, challenging but not exhausting! The session calories were a crazy 766! Out of curiosity I put it on this morning and found out I can do a "workout" at my desk at 115cal/hour. So I assume you have to subtract that from exercise calories? Or are the calories just BS and should be ignored? Also I was "out of The Zone" (109-138) for almost my entire workout. How does this zone get established?? Is it a so-called fat burning zone??

Replies

  • MeanderingMammal
    MeanderingMammal Posts: 7,866 Member
    edited August 2016
    So HR isn't a reliable indicator of calorie expenditure when you're not in the aerobic, range. Sitting at your desk isn't aerobic, your HR is too low, so any calorie approximation based on that input is unreliable.

    I'd suggest that nearly 800 cals for 4 miles is only realistic if you weigh in excess of 300lbs. Personally, at 160lbs, I'll burn about 100 per mile running and 50 per mile walking.

    The observation I'd make is that if you're running at 160bpm, you're running too fast. Slow it down and you'll be able to run for longer.

    For my runs of greater than an hour I'll generally be about 150bpm.
  • Sued0nim
    Sued0nim Posts: 17,456 Member
    Because you moved out of steady state and into intervals that calorie estimate will be way out ...I agree with @MeanderingMammal on the estimate
  • MeanderingMammal
    MeanderingMammal Posts: 7,866 Member
    edited August 2016
    Sued0nim wrote: »
    Because you moved out of steady state and into intervals that calorie estimate will be way out ...

    Errors from pace transition wouldn't be significant in walk/ run intervals as described. The issue with shorter, or more intense, intervals is a combination of HR reduction times and progressive HR elevation. When you're talking 20-30 seconds of maximal effort with a 60 second recovery, the fluctuations in effort are never accounted for, but if you're slowing into a longer walk interval then you're only talking about an error of 20-30 cals.

    It's a reasonable response to the endless posts extolling the virtues of an HRM when doing HIIT, but for relatively low to moderate intensity the error isn't high.

  • CincyNeid
    CincyNeid Posts: 1,249 Member
    Springerrr wrote: »
    ? Also I was "out of The Zone" (109-138) for almost my entire workout. How does this zone get established?? Is it a so-called fat burning zone??

    To do it correctly : You would have to find your maximum Heart Rate ThresHold. Which should be done under the supervision of a health professional. And each Zone is a percentage of that HRTH. Everyone is different and your HRTH is unique to you.
  • Springerrr
    Springerrr Posts: 44 Member
    MeanderingMammal wrote: »
    I'd suggest that nearly 800 cals for 4 miles is only realistic if you weigh in excess of 300lbs. Personally, at 160lbs, I'll burn about 100 per mile running and 50 per mile walking.

    Yes, exactly, I weigh 185, which I entered into the FT4 before using it. I am highly skeptical.
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