Accurate Calorie Burn

mkveli2pac
mkveli2pac Posts: 31 Member
edited November 17 in Fitness and Exercise
I have been using a recumbent bike for quite some time now and unfortunately I cannot determine an accurate calorie burn. The Polar monitor that is built into the bike tells me I am burning 1050 calories for riding 30 mins at a pace of 13.8 MPH at a medium level of resistance. I know this is not even close to being correct. I have been estimating I have been burning about 500 calories. Is there a way I can figure out how many calories I have been burning?

Yes, I know the website has a caloric burn calculator, but I was told that is not even too accurate.

Replies

  • alispatred
    alispatred Posts: 5 Member
    the equipment at the gym is base on a average male, weight height so on, so it will never give a correct reading. you also have to take into account back ground calories these are the normal calories we burn during the day. the best thing is a heart monitor with a watch which doesn't start burning calories until your heart rate reaches 80+ this way its a true calorie burn, remember the fitter you get the less calories you will burn during a workout as your heart rate will take longer to get to a burn rate.

    hope this helps
  • glevinso
    glevinso Posts: 1,895 Member
    If you use one of the spin bikes that has a built in power meter (IE it shows you watts) then you can get very accurate numbers. Aside from that HRM can make a reasonable guess, but it will only be just that: a reasonable guess.
  • sijomial
    sijomial Posts: 19,809 Member
    Yep that 1050 for 30mins is a joke, 500 for 30 minutes would be highly unlikely for what you are describing as slow pace with moderate resistence, as a very rough guess maybe go for 250?

    850 - 870 in an hour is about my maximal effort (power meter verified) and I've got a very good VO2 max and cycle a lot.

    By the way this is nonsense "remember the fitter you get the less calories you will burn during a workout as your heart rate will take longer to get to a burn rate".
    I think what he means is that an uncalibrated HRM will estimate a lower burn if your heartrate is low. That's just a failing with using HRMs as a means for estimating calories.

    The fitter you are the more power you can generate and maintain for longer.
  • mkveli2pac
    mkveli2pac Posts: 31 Member
    Thanks for everyone's advice, I appreciate it.
  • mkveli2pac
    mkveli2pac Posts: 31 Member
    glevinso wrote: »
    If you use one of the spin bikes that has a built in power meter (IE it shows you watts) then you can get very accurate numbers. Aside from that HRM can make a reasonable guess, but it will only be just that: a reasonable guess.

    It is not a spin bike, it is a recumbent bike, but it does have the power meter you speak of. It tells me my power wattage is 200.

  • glevinso
    glevinso Posts: 1,895 Member
    edited April 2015
    mkveli2pac wrote: »
    glevinso wrote: »
    If you use one of the spin bikes that has a built in power meter (IE it shows you watts) then you can get very accurate numbers. Aside from that HRM can make a reasonable guess, but it will only be just that: a reasonable guess.

    It is not a spin bike, it is a recumbent bike, but it does have the power meter you speak of. It tells me my power wattage is 200.


    If you average 200 watts for the whole hour you calorie burn will be 720 (+/- 5% or so).

    Edit: There is a fairly convenient conversion from watts to calories in that if you cycle at a reasonably steady state, you can multiply your average power by 3.6 and get calories. If you are doing intervals that will be a bit off. Regardless, you should be able to reasonably work with your average power number.

    Edit2: This is an accident of physics. The power meter is measuring the actual amount of energy you are transferring into the pedals. 1 watt = 1joule per second. There are 4.18joules per calorie (or 4.18kj per kcal). The human body also just so happens to be about 25% efficient when cycling. IE you burn 100 calories in your body, 25 of those calories actually went into your pedals. The rest was burned off as waste heat and other inefficiencies. Therefore there is a happy accident that you can 1 to 1 correlate kilojoules expended into the pedals with calories burned by your body. To get from "average watts" to KJ you multiply by 3.6:

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