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Thread: fat burn during cardio ?

  1. #1
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    fat burn during cardio ?

    I know all you guys are trying to preserve muscle while doing cardio, so you try to stay within the "fat burning zone". Now it seems logical that if I burn more calories, I will burn more fat (I usually do HIGH intensity cardio 1-2 times a week 75-92% of max heart rate).So my question is, why does everyone say stay within 65-70% of max heart rate? If I burn less calories, why is it so much more beneficial to stay in "the zone"? Thanks in advance!

  2. #2
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    Below
    Last edited by SVTMuscle*; 12-17-2006 at 07:28 PM.

  3. #3
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    Source- Bodybuilding.com
    The Difference

    Low intensity cardio is much different than high intensity cardio. In order to understand how these are different, I will first have to explain some things to you.

    The breakdown of fats in your body is called lipolysis. The enzyme in the body that is responsible for lipolysis is called lipase. Lipase turns fats, or triglycerides, into three unbound fatty acids (FFA) and one glycerol molecule. So pretty much all you need to know by now is that lipase, the breakdown of fats, is caused partly by cardio.

    Mobilization is the breakdown of triglycerides into glycerol and FFA's for energy. So basically you can think of mobilization as breaking down fat in your body for future possible use. Oxidation is the point at which the fatty acids that were mobilized were actually burned. Fats that were mobilized for possible use do not have to be burned and can be converted back into new triglycerides.

    Higher Intensity = Lower FFA's


    Studies have shown that as the intensity of exercise increases, the lower the amount of FFA's (fats that have been mobilized) there are in your bloodstream. By now, most of you are thinking: Ok, since high intensity cardio create less mobilization than low intensity cardio, then low intensity burns more fat. This is not necessarily true. Although mobilization of fats goes down as intensity increases, the total oxidation of total fats is greater because more calories were burned, but at a lower rate of burned fat.

    During low intensity cardio, the rate at which oxidation occurs in FFA's in much higher than in high intensity cardio. By now you are probably going nuts thinking: Ok, in low intensity cardio there is more mobilization and a higher rate of oxidation than in high intensity cardio. So why is high intensity cardio better for burning fat? It is better for burning fat because although the amount of FFA's being burned is lower, the amount of total fat is much greater.

  4. #4
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    Intramuscular Triglycerides

    So where is this other fat coming from? The other fat is called intramuscular triglycerides. Intramuscular triglycerides are droplets of triglycerides that are stored inside the muscle fiber. This places fat closer to the site of energy production in the muscle fiber and therefore allows intramuscular fat to be utilized at a slightly higher rate than adipose tissue (stored body fat).

    Here is an example:

    Say you burn 200 calories doing low intensity cardio and 90% of those calories came from fat. That means you burned 180 calories from fat and 20 from other sources. If you would have done high intensity cardio during that period, you might have burned 300 calories and 75% of those calories were burned from fat. That means you burned 225 calories from fat and 75 calories from other sources.
    (keep in mind these figures are used for only a demonstration and do not
    correctly represent the percentage of fat actually burned during cardio)


    With high intensity cardio, you burn more fat and calories than low intensity cardio in the same period of time.

  5. #5
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    Hey Prnce,

    If you have time read this thread...

    http://forums.steroid.com/showthread.php?t=240522

    almost every question u can possibly have will be answered... great discussion..

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    Thanks

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    It all about maximizing fat loss with minimal muscle loss.

  8. #8
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    I used to think the same way but sence i changed to low intenc cardio in the am I lost 11 lbs in 4 weeks. It works for me

  9. #9
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    Quote Originally Posted by FaizakaFez
    Hey Prnce,

    If you have time read this thread...

    http://forums.steroid.com/showthread.php?t=240522

    almost every question u can possibly have will be answered... great discussion..
    You got there before me :-).










    Quote Originally Posted by crazycrab
    I used to think the same way but sence i changed to low intenc cardio in the am I lost 11 lbs in 4 weeks. It works for me
    Nice, 11lbs. of fat too I'm sure. Sounds just about right to me. Keep up the good work.

  10. #10
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    how long do you do cardio for?

  11. #11
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    Quote Originally Posted by violator1
    how long do you do cardio for?

    35-45 mins.

    Remember you will include warm up and cool down in that time frame.

  12. #12
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    Nobody knows right now, the exercise physiology world has paper after paper conflicting each other on this subject along with what is the best rep vs volume for hypertropy. In the lab you can measure what energy source someone is using durning exercise based on a principle called the Respritory Exchange Ratio. The gyst of this is that carbo's and Fat have different amounts of carbon atoms attached to them. One can calculate what energy source is being used predominatly by the amount of CO2 gas being exhaled in the breath. It was thought to be pretty reliable but now its being reexamined for its validity. This has occured in the last 2 years. Certianly from what I have seen in the lab. You dont want to have to high a intensity which I have seen vary from as low as 55% all the way up to were a person is using nothing but carbs as an energy source. To contrast I have seen people work as high as 75-80 of maxhr and still be well within the "fat burning zone", bottom line is what ever has worked for you in the past is probable what you should stick with.

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