Another HRM Question....

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dani41
dani41 Posts: 8 Member
in Fitness and Exercise
I'm not new to running, but I am new to HRMs. I was a pretty regular runner (trained and ran a few marathons and halves) but due to injuries, I took the last 3 months off. I've been working out regularly and doing round 2 of P90X at the moment, so my body knows extreme. This morning I ran a 5k fundraiser and it was definitely not my best time. I ran it in exactly 31 minutes, which is a 10 minute mile. I decided to wear my HRM and after the race I checked my stats - it had me burning 700 calories! My maximum heart rate is 186 and when I glanced at the monitor I keep seeing my HR in the 170s (stats showed that I also reached 186 at one point). I usually run with a Garmin(w/o HRM) and that guesstimates me at around 400 for those runs. The monitor I'm using is a Timex 685 WITH a chest strap. I KNOW it's not the best monitor on the market, but I had seen some good reviews for this and I can't imagine with a chest strap it would be a couple of hundred calories off. I guess what I'm asking is - is this possible? Maybe my cardio while running isn't as up to speed as it used to be and I'm working harder?

FYI- for comparison, this HRM has me doing KenpoX and PlyoX around 700 calories as well. I definitely push the intensity when doing P90X and those numbers seem to mesh with what others claim on various websites. For it to be somewhat consistent with what others are experiencing with P90X but then be so much higher than I was expecting, really has me second guessing my diet while training for future races.

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  • balance9
    balance9 Posts: 160
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    An average 150lb woman running at 6 mph (10 min mile) burns roughly 600 calories/hr. When you set up the Timex, does it ask you to enter weight info? If two women weighing the same (body fat, etc.) run the same distance/time, they will burn *roughly* the same amount of calories, irregardless of heart rate. The one with the higher heart rate will utilize a different energy substrate (i.e. higher % glucose/lower body fat, but even this will balance out over the course of the day), but same total calories. Not sure if I explained that well- Does that make sense?
  • dani41
    dani41 Posts: 8 Member
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    Yes, you explained it just fine - and thank you for your response. Yes, my weight was entered along with my max HR. I do know that a 10 min mile is roughly 100 calories, but according to a trainer I spoke with last year, due to my high muscle mass in my legs, I probably burn more. I'm a muscular 162lbs, who really has maybe another 10lbs that I could lose without looking too thin in certain areas in my body. In all honesty, I wouldn't be surprised with a 500 cal burn, but it's the 700 that is blowing me away. I just wonder if my HRM is faulty.
  • Azdak
    Azdak Posts: 8,281 Member
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    The HRM is way off. Here is one important question: Does the HRM allow you to input a separate VO2 max number? If not, then it has to be using some type of constant multiplier to guess at calories burned--in which case the number can be way, way off. I can only assume they are using preset VO2 max numbers. Because your HR is higher in the range, I can only assume the HRM thinks you are going at max effot the whole time--although even that isn't enough to explain why the number on your HRM is about double what you actually burned.
  • Azdak
    Azdak Posts: 8,281 Member
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    Yes, you explained it just fine - and thank you for your response. Yes, my weight was entered along with my max HR. I do know that a 10 min mile is roughly 100 calories, but according to a trainer I spoke with last year, due to my high muscle mass in my legs, I probably burn more. I'm a muscular 162lbs, who really has maybe another 10lbs that I could lose without looking too thin in certain areas in my body. In all honesty, I wouldn't be surprised with a 500 cal burn, but it's the 700 that is blowing me away. I just wonder if my HRM is faulty.

    At a 10 min mile, your calories burned per hour is about 10.5 times your body weight in kg., or roughly 125-130 Cal/mile (doing the math in my head). Your "muscular" legs have little to do with that. That's just one of those silly things that trainers say when they haven't got a clue, but still want to impress you.
  • DrBorkBork
    DrBorkBork Posts: 4,099 Member
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    I think 700 sounds about right, honestly. When I did my first 5k, I walked most of it and burnt close to 1,000, finishing in an hour, but I'm a lot heavier than you, so 700 sounds right to me :)

    then again what do I know? I just started running last month.
  • whyflysouth
    whyflysouth Posts: 308 Member
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    Yes, you explained it just fine - and thank you for your response. Yes, my weight was entered along with my max HR. I do know that a 10 min mile is roughly 100 calories, but according to a trainer I spoke with last year, due to my high muscle mass in my legs, I probably burn more. I'm a muscular 162lbs, who really has maybe another 10lbs that I could lose without looking too thin in certain areas in my body. In all honesty, I wouldn't be surprised with a 500 cal burn, but it's the 700 that is blowing me away. I just wonder if my HRM is faulty.

    At a 10 min mile, your calories burned per hour is about 10.5 times your body weight in kg., or roughly 125-130 Cal/mile (doing the math in my head). Your "muscular" legs have little to do with that. That's just one of those silly things that trainers say when they haven't got a clue, but still want to impress you.

    The only reason I track calories is to know what I should "eat back" or not. considering that these timex hrms like to flatter us with high calories, do you have any advice as to what we should eat back regarding our exercise calories with them? maybe just 60% of what the HRM tells us?
  • HonestOmnivore
    HonestOmnivore Posts: 1,356 Member
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    http://www.concept2.com/us/interactive/calculators/vo2max.asp

    How does this look for a VO2max calculator? A friend did his graduate studies at Ohio University (exercise physiology I think) and he sent me this link.
  • Azdak
    Azdak Posts: 8,281 Member
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    http://www.concept2.com/us/interactive/calculators/vo2max.asp

    How does this look for a VO2max calculator? A friend did his graduate studies at Ohio University (exercise physiology I think) and he sent me this link.

    It probably works pretty well if you are trained and experienced using the Concept 2 rower. This would fall under the heading of a "field test", which means that familiarization with the technique will have a significant effect on the accuracy of the results. This is true when doing other field tests such as a 1-mile run, Cooper 12-min test, etc. Given the greater complexity of the rowing movement, I would expect a greater degree of training would be required to get consistent results--just to learn how to pace yourself.

    But, for rowers, it's probably excellent.
  • mromnek
    mromnek Posts: 325
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    bump to get on my topics

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