heart rate monitor problems ??

nukehiker
nukehiker Posts: 457
edited September 24 in Fitness and Exercise
so on sunday I think, I purchased a heart rate monitor at walmart for about $38. The first time I used it yesterday for my 30 minute elliptical cardio session it said i used about 440 calories. the machines display was about 370 for this same period. now today i use it and it reads about 300 for todays first 30 minute session and about 260 for the second one. again the machines read out is about 350-375 for the same 30 minute program. now what figure should i use to record todays exercise ? and any thoughts on this darn heart rate monitor ???

Replies

  • hjollyrn
    hjollyrn Posts: 208 Member
    I had similar questions when I first got mine. Answers were: go with what the heart rate monitor says. It's most accurate!
  • rileysowner
    rileysowner Posts: 8,327 Member
    Generally the HRM will be more accurate. All the machine does is take your information, and run it through a mathematical equation to estimate the number of calories burned. How hard you work doesn't matter, that is why the numbers are the same every time on the machine.

    You HRM, by measuring your heart rate seeks to measure how hard you are working. That means the numbers will be different for the same workout on different days. Some days you work harder with a higher heart rate. The machine never measures that.
  • nukehiker
    nukehiker Posts: 457
    well I did the workout the same intensity, length , resistance as I always do so all the factors are still the same just not sure why the big difference ??
  • rileysowner
    rileysowner Posts: 8,327 Member
    That is your perception, but the reality is that your body doesn't really function that way. I can do the exact same exercise on two different day, go at it with full intensity, but burn different numbers of calories because 100% intensity on one day will be different that 100% intensity on another day. Both are 100%, but due to a whole variety of factors beyond your control that 100% is different. That is why when you watch high level athletes their performance can be so different from day to day. I remember watching the Winter Olympics and seeing how one day and speed skater would do really well, the next not so much. The difference was measured in 10ths or 100th of a second, but that is the difference between a podium finish and an also ran. I am sure they went 100% both times, but the results were different. So to with the number of calories burned from one day to the next, or for that matter from one exercise session to the next.

    Taking this all into consideration, and adding the fact that MFP has you eat your calories back, that is why having a HRM is so important. If you are not burning as many calories as you think you are, then you would not really want to eat them back. Or the opposite, if you have burned more calories than you think, you might want to eat more calories. Generally the machine estimates are too high, sometimes they are not. If you HRM has you enter your weight and age and the like, it is probably more accurate than any machine estimate.
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