Fat Burning Zone? When does it start?

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CountryGirl8542
CountryGirl8542 Posts: 449 Member
in Fitness and Exercise
Is it true that the first 20 minutes of a jog only burns calories you have consumed that day? and anything after 20 minutes is burning stored fat? What happens to my body when I do 30 minute jogs first thing in the morning with an empty stomach... and some water?

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  • Wiltord1982
    Wiltord1982 Posts: 312 Member
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    IMO, cardio is cardio. Empty stomach or not. The best cardio is the one you will like, will do regularly and will do for a sustained period of time. It's better to run 60 minutes with an average 140 bpm than running 20 minutes with an average 160 bpm.

    Just enjoy yourself :)
  • Mr_Knight
    Mr_Knight Posts: 9,532 Member
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    Is it true that the first 20 minutes of a jog only burns calories you have consumed that day? and anything after 20 minutes is burning stored fat?

    No, and no. Your body can't metabolize fat fast enough to support the energy requirements for running, so there is never a period during running when you are only burning fat.
  • daniellemm1
    daniellemm1 Posts: 465 Member
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    bump
  • CountryGirl8542
    CountryGirl8542 Posts: 449 Member
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    IMO, cardio is cardio. Empty stomach or not. The best cardio is the one you will like, will do regularly and will do for a sustained period of time. It's better to run 60 minutes with an average 140 bpm than running 20 minutes with an average 160 bpm.

    Just enjoy yourself :)

    What is the difference in running for 60 minutes with an average heart rate of 140bpm and running for 20 minutes with an average heart rate of 160 bmp? Burn more calories????
  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
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    Is it true that the first 20 minutes of a jog only burns calories you have consumed that day? and anything after 20 minutes is burning stored fat? What happens to my body when I do 30 minute jogs first thing in the morning with an empty stomach... and some water?

    No.

    A 20 minute jog will on average burn about 200 calories, we eat far more than that.

    Forget "fat burning Zones". For the sake of calorie burning, HR zones are pointless.
    HR zones are over generalized and even if you are using the correct ones - yes, you burn more fat at a certain zone, however, it is low intensity and the total calories burned is low. When you up intensity, you burn fewer "fat" calories, but the total calories burned is higher which means you still end up burning more fat calories.

    TLDR - forget fat burning zones.
  • BrianSharpe
    BrianSharpe Posts: 9,248 Member
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    Forget you ever heard the term "fat burning zone".

    In a nutshell it's low intensity cardio (50 to 60% of maxHR) whereby you burn a higher proportion of calories from fat but you burn a significantly lower number of calories overall.

    Burning fat for fuel while exercising has nothing to do with long term fat loss. You can lose fat without exercise at all, just eat at a modest caloric deficit. Exercise promotes good health and fitness and may help you lose a bit more weight by creating a little bigger caloric deficit.
  • takumaku
    takumaku Posts: 352 Member
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    No, and no. Your body can't metabolize fat fast enough to support the energy requirements for running, so there is never a period during running when you are only burning fat.

    As a runner, I would disagree with your statement. My understanding is if someone is running short distances (10k or less), then the body will burn the sugars stored in the muscle for fuel. When distances increases above this (i.e. steady state running), the body will begin to tap into some fat for fuel.
  • 3dogsrunning
    3dogsrunning Posts: 27,167 Member
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    IMO, cardio is cardio. Empty stomach or not. The best cardio is the one you will like, will do regularly and will do for a sustained period of time. It's better to run 60 minutes with an average 140 bpm than running 20 minutes with an average 160 bpm.

    Just enjoy yourself :)

    What is the difference in running for 60 minutes with an average heart rate of 140bpm and running for 20 minutes with an average heart rate of 160 bmp? Burn more calories????

    HR is not directly related to calories burned.



    Check out Azdak's blogs on the matter.

    http://www.myfitnesspal.com/blog/Azdak?month=201005
  • Mr_Knight
    Mr_Knight Posts: 9,532 Member
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    IMO, cardio is cardio. Empty stomach or not. The best cardio is the one you will like, will do regularly and will do for a sustained period of time. It's better to run 60 minutes with an average 140 bpm than running 20 minutes with an average 160 bpm.

    Just enjoy yourself :)

    What is the difference in running for 60 minutes with an average heart rate of 140bpm and running for 20 minutes with an average heart rate of 160 bmp? Burn more calories????

    Yes. All else being equal, you will go a considerably further distance with the slower heart rate, and calorie burn is proportional to distance run. There are also meaningful physiological changes that only come with "time in the saddle" - whether those matter to you depends on your ultimate goals, of course.
  • CountryGirl8542
    CountryGirl8542 Posts: 449 Member
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    Thanks for the replies everyone :)
  • ElliottTN
    ElliottTN Posts: 1,614 Member
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    Research your glycogen stores in relation to excersise and this should become more clear to you.

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