Quiz time.

  • Posted by a hidden member.
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    Jul 09, 2008 1:13 PM GMT
    icon_question.gifQuestion: 20 y/o 5' 170 runs 3mi a day which pace yields the best results and why?

    A: 8min mile with HR of 190
    B: 13min mile with HR of 140

    I will give the answer after 10 responses should no one come up with the correct answer. The reason for this is that I have seen alot of people still preaching to a certain myth when it comes to cardio and fat burning.
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    Jul 09, 2008 3:54 PM GMT
    hmm then why not just debunk the myth and skip the quiz altogether? Lol i guess the suspense is more fun icon_smile.gif
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    Jul 09, 2008 4:06 PM GMT
    OK, I'll be a sucker on this one. Unless it's a trick question, I've got a 50/50 chance right? I"m guessing (emphasis on guess) that it's "B" - 13 min/mile. I'm basing this on the running slower for such a short distance allows the heart to maintain an elevated rate for a longer period of time ( 13 x 3 = 39 min) vs (8 x 3 = 24 min). Seems logical that the longer the heart rate is raised the better your chances of keeping a faster metabolism therefore burning more calories.

    Well, I thought it sounded good anyway! LOL
  • MSUBioNerd

    Posts: 1813

    Jul 09, 2008 5:00 PM GMT
    It really depends on what you're using as your metric of "best", actually.

    In terms of maximum pulse, the general formula is 220 - age. In this example, that's 200. Option A means you're running at 95% maximum pulse, while option B is is 70% maximum pulse. This makes option B the better choice, because sustaining a pace of greater than 70% maximum pulse for normal people/ 80% for elite athletes is generally considered a bad idea.

    In terms of calories burned, you're slightly better going for option A--while you'll burn nearly equivalent calories over the length of the run regardless of the speed, a proper calculation of caloric burn would take into account basal metabolism as well, and that's not typically subtracted out when determining the caloric burn of your cardio. However, that's very unlikely to overpower the possible heart complications of the sustained very high pulse, so probably this isn't your metric.

    In terms of running a competitive 5k, though, option A is clearly the better choice if you can do it. The thing is it's unlikely you can do that under these guidelines--if running 3 miles at 8 minutes per mile puts your pulse up at 190, you probably can't maintain that pace for that distance, at least not on a daily basis.

    But I'm going to guess that you're looking for option B, based on the max pulse argument.
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    Jul 09, 2008 5:10 PM GMT
    Well I'd measure his 'best result' as total distance traveled...so the 8min guy is gonna win.
  • MSUBioNerd

    Posts: 1813

    Jul 09, 2008 5:13 PM GMT
    "Well I'd measure his 'best result' as total distance traveled...so the 8min guy is gonna win.

    Heh, not quite. If you read the details of it, it's 3 miles either way, it's just done faster if it's at 8 minutes per mile.
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    Jul 09, 2008 10:45 PM GMT
    suspense is always good.

    Going by the pulse rate argument is close. I should of put B at 120HR, was in a hurry and did the math in my head. This would probably made it easier.

    True A may appear to burn more calories, but is he burning more fat?
  • Posted by a hidden member.
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    Jul 10, 2008 1:13 AM GMT
    tonyp321 saidicon_question.gifQuestion: 20 y/o 5' 170 runs 3mi a day which pace yields the best results and why?

    A: 8min mile with HR of 190
    B: 13min mile with HR of 140

    I will give the answer after 10 responses should no one come up with the correct answer. The reason for this is that I have seen alot of people still preaching to a certain myth when it comes to cardio and fat burning.


    Tony, your results are relative to what we are trying to achieve and the variables you decide to use...

    Research shows that the higher the HR, the more the body relies on carbohydrates as the main energy source; the lower the intensity the more the body relies on fat as the main energy source. You should mix both to maximize cardio output, conditioning, and physical endurance.

    With respect to distance, then the person running 3 miles @ either 8 min mile or 13 min mile would burn the same amount of calories respectively because calories burned is calculated by distance x weight and does not take into account heart rate...

    At a lower intensity, roughly 50% of calories spent are fat...At higher intensities, it can range from 33-40% of calories spent as fat...

    In the question you present, the lower intensity would burn more calories in fat, because you did not overall time into consideration...your main variable is distance.

    Now...if you run at 8 min mile vs. 13 min mile over the course of a half hour, for example, using time as the variable, then the activity with the higher intensity will burn more calories and burn more fat calories, even though you get more bang for your buck running at the slower intensity...

    Good question!

    Regards,
    Duane, MPH in Health Promotion and Education





  • MSUBioNerd

    Posts: 1813

    Jul 10, 2008 3:32 AM GMT
    "With respect to distance, then the person running 3 miles @ either 8 min mile or 13 min mile would burn the same amount of calories respectively because calories burned is calculated by distance x weight and does not take into account heart rate..."

    Not quite true for the reason I gave--the basal metabolism issue. In this example,

    Option A involves burning X1 calories for the 3 miles run in 24 minutes.

    Option B involves burning X2 calories for the 3 miles run in 39 minutes.

    We will assume X1 = X2 (though in reality they will be close but not exactly equal--any given gait will have a maximal efficiency at one speed, and will be less efficient at others. The most efficient gait at 8 minutes per mile is not guaranteed to have the exact same efficiency as the most efficient gait at 13 minutes per mile.)

    However...in the 39 minutes option B takes to burn X2 calories, option A would have burned X1 calories PLUS some number from basal metabolism for the 15 minutes of rest. Therefore, option A results in more calories being burned in that 39 minute window.

    Now that the pulse has been changed and the terms of how best is to be determined has been defined, though, that might be a bit moot. ;)
  • Posted by a hidden member.
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    Jul 10, 2008 4:10 AM GMT
    Duane gets the cookie.

    Ill write more of a followup later I need to review first for errors and right now all the words are fuzzy, finish 48hr shift and up for 72. Time for bed.