My heart rate monitor experience

So two of my buddies recently found a great deal on the Timex Road Trainer heart rate monitor:
http://www.amazon.com/Timex-Ironman-Trainer-Monitor-Orange/dp/B001GWYACK/ref=sr_1_3?ie=UTF8&qid=1379532412&sr=8-3&keywords=timex+heart+rate+monitor

They have had them at least 6 weeks by now and we were astonished at the amount of calories we typically burn in workouts. Before using these we would generally only put about 75% of our workout time in MFP as General circuit training. So, for a typical 1hr workout we'd claim 45 minutes of circuit training (since our workouts weren't necessarily 100% circuit training) and it would tell us just under 500 calories were burned.

Now that they use the heart rate monitors they register anywhere from 700-1400+ calorie workouts (some of our workouts go for 75 minutes). It just seems outrageous. When using these monitors (watches with chest strap) you put in your age/weight/sex and from our experience it lines up very closesly with any cardio machine in the gym with a heart rate monitor.

I didn't buy one but I did borrow my friends for a leg workout recently and he input my vitals and off I went. It told me I burned ~1150 calories in my typical leg workout + abs ( I believe the total tracking time including warmup was about 60 minutes). As you can imagine our workouts are intense and leave us exhausted and drenched in sweat. For this particular workout my avg heart rate reported as 154 (this includes warmup time and cooldown time in the shower) with a max somewhere around 175.

Seems like alot, but I dont' see how it could be wrong.

Replies

  • TechOutside
    TechOutside Posts: 101 Member
    I bought the zephyr bluetooth and use icardio as my workouts beat me up way more than bike riding or the elliptical and it didn't seem right to me that only a couple hundred was expended.

    I am getting closer to 700 to 900 calories expended according to mine but I only spend about 45 minutes at a time, sometimes I'll go more, but the app let's me know when I drop down a heart rate zone (interrupting my music) which lets me know when to get to the next set. So I have been resting less and moving more, which shortens my workouts trying to stay in the higher zones.

    I don't know if it's right, wrong or indifferent, but so far it's working for me.
  • nytrifisoul
    nytrifisoul Posts: 499 Member
    What i find great about using the HRM is that you can change your routine the second your bpm starts dropping and keep your average bpm high which helps you burn more. Without the bpm i know i tend to stay keep a high pace and then after awhile my bpm drops and im already maxed out on what my knees can handle while running.
  • sugarkane1234
    sugarkane1234 Posts: 51 Member
    It's my understanding that HRMs are only accurate for steady-state cardio. They will give inflated calorie burn info for circuit or strength training. I couldn't tell you why exactly this is, but I know there have been threads about it before. Try the search function or google.
  • ljprofitt
    ljprofitt Posts: 5 Member
    The calculation used to calculate calories burned relies on a direct relationship between your heart rate and your oxygen intake. Thus, the heart rate monitors are assuming that you are performing aerobic cardio exercise when they make the calculation. Because circuit training is a primarily anaerobic exercise, your heart rate does not directly correspond to oxygen intake and the numbers will be incorrect.
  • Azdak
    Azdak Posts: 8,281 Member
    Timex HRMs are known for wildly overestimating calories. And all HRMs are inaccurate when it comes to strength training.
  • Fuzzystump
    Fuzzystump Posts: 4 Member
    Thanks, that link provided makes some sense (http://www.sparkpeople.com/community/ask_the_experts.asp?q=75).

    It would lead me to believe that on leg days, for instance, it would be relatively accurate due to the large amount of muscle being used.

    To be truthful, the majority of our workouts revolve around high intensity and low rest between sets and often times NO rest and doing opposing muscle group supersets. In the case of the leg workout I mentioned in the original post where I burned 1150ish calories I did straight high intensity sets to failure for the first couple excercises (squats then leg press) then utilized super sets for some of the "easier" stuff such as leg extensions/leg curls.