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glycogen use

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cliff_vtr
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2006/07/14 12:17:09 (permalink)
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glycogen use

Is muscle glycogen use local. I mean if my quads are holding say 50g of glycogen and I do some heavy squats, does it mean that once this is spent thats it or can one muscle draw on glycogen from other muscles.

Or does it work that blood sugar supplies the glucose to the muscles and muscle glycogen tops up blood sugar as it drops ???

Is it glucose that creates ATP, whats the connection between ATP and glucose ?

Paul
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    OoOGazOoO
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    RE: glycogen use 2006/07/14 15:41:10 (permalink)
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    Well the glucose in the muscles is used via glycolysis which makes pyruvate, which then in turn, forms the ATP.

    I would also be interested to hear your first question though, i would imagine it is a bit of both, i.e. some from the muscles where it is being worked, but also from other glycogen stores, i.e. once those smallers ones maybe become depleted.
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    Big D
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    RE: glycogen use 2006/07/14 17:04:37 (permalink)
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    ORIGINAL: cliff_vtr

    Is muscle glycogen use local. I mean if my quads are holding say 50g of glycogen and I do some heavy squats, does it mean that once this is spent thats it or can one muscle draw on glycogen from other muscles.

    Or does it work that blood sugar supplies the glucose to the muscles and muscle glycogen tops up blood sugar as it drops ???

    Is it glucose that creates ATP, whats the connection between ATP and glucose ?

    Paul


    answer best i can put it... so here goes.

    the energy system mainly used within weight training is the anaerobic glycolytic system (have a read around on net for more info) i.e. muscle glycogen system.

    firstly, your muscles can draw upon glycogen stores from other areas of the body. otherwise as you put it like doing squats after your glycogen stores are fully depleted from the legs you wouldnt be able to walk. as in theory you would have no energy. however the fatigue will come from the build of lactic acid which is formed in the break down of ATP. which shows that this fast process comes at a cost. (the fast process relates to the glucose bypassing oxygen pathways to produce energy quicker)

    secondly, blood sugar is in the bloodSTREAM, so in effect is shuttled to where it is needed and when it is needed.

    thirdly, the connection between glucose and ATP is that one molecule of glucose which is broken down from glycogen using oxygen is used in the anaerobic glycolytic energy system and the aerobic system.

    in the anaerobic system one glucose molecule is added to ADP (adenosine diphosphate) and produces only 2 ATP for energy.

    in the aerobic energy system 1 glucose module produces up to 38 ATP molecules.

    and after all that ...... there is the breakdown of fat for energy which we know can only be broken when using the aerobic energy system.

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    cliff_vtr
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    RE: glycogen use 2006/07/14 17:17:15 (permalink)
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    just wiki-eed it and in aerobic its 36ATP as 2 are consumed in the process.

    Also muscle glycogen is local, it can only be used by that muscle.

    Also found that fat or rather triglycerides are broken down to glycerol and then enter the same point in the process as glycogen.

    What I'd like to know: is ATP primarly recycled or is it fully created. As I read it mostly recycled from ADP. however if glucose breaks down into ATP then surely its synthesised from scratch ??. I got 2 conflicting pieces of info here.


    Paul
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    JMA
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    RE: glycogen use 2006/07/14 17:20:23 (permalink)
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    Glycogen stored in the muscle can only be used by that muscle, the other store of glycogen is in the liver which can supply glycogen where and when required.
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    cliff_vtr
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    RE: glycogen use 2006/07/14 17:22:31 (permalink)
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    yeah about 100g held in the liver and 1% held in muscles but coz there is more muscle than liver in the body there is overall more glycogen in the bodys muscle than in the liver
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    JMA
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    RE: glycogen use 2006/07/14 17:25:50 (permalink)
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    Wieght training is not as glycogen delepting as most think though. Unless you set out to do a proper depletion work out you will still have plenty of glycogen (in your muscles) post work out.

    Hope you find your answers is an interesting topic but i have to go get a train, have a nice weekend my friend.
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    OoOGazOoO
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    RE: glycogen use 2006/07/14 17:33:43 (permalink)
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    Paul.

    I thought liver glycogen stores werent as much as 100 grams? ? ?
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    cliff_vtr
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    RE: glycogen use 2006/07/14 17:38:12 (permalink)
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    yeah I read that your body holds around 500g of glycogen which is about 2000cals. An average weight training session will only burn about 200cals.

    So assuming glycogen is reasonably topped up you have more than enough.

    Which now brings to the question of why are carbs needed post workout if glycogen is reasonably topped prior to workout.

    Paul
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    cliff_vtr
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    RE: glycogen use 2006/07/14 17:39:04 (permalink)
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    liver stores may be less than 100g, its just what I read. I guess everyone is different.

    Paul
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    OoOGazOoO
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    RE: glycogen use 2006/07/14 17:44:16 (permalink)
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    Yeh true.

    I would imagine the EPOC following weight training is quite large if it is an intense session, therefore more glycogen will be used in order to spare lean tissue.

    PWO carbs to eliminate cortisol.
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    Big D
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    RE: glycogen use 2006/07/14 17:45:25 (permalink)
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    ORIGINAL: cliff_vtr

    just wiki-eed it and in aerobic its 36ATP as 2 are consumed in the process.

    Also muscle glycogen is local, it can only be used by that muscle.

    Also found that fat or rather triglycerides are broken down to glycerol and then enter the same point in the process as glycogen.

    What I'd like to know: is ATP primarly recycled or is it fully created. As I read it mostly recycled from ADP. however if glucose breaks down into ATP then surely its synthesised from scratch ??. I got 2 conflicting pieces of info here.


    Paul



    yes muscles cannot directly use 'another' muscles glycogen stores, however its much more complicated than say me asking to borrow your dumbells for a set. the body will use other glycogen stores as energy in different ways. when muscle glycogen depletes the contribution from blood glucose increases to the muscles which need it the most. rather than filling other not so needy muscles being topped up with glycogen.

    and yes your right 2 ATP are used in the anaerobic process, however the figure of 38 ATP is not always the amount produced. just a rough amount, as are many amounts in energy pathways.

    for more info on fat being used for energy look into lipolysis.

    as for your other question, from what i have been taught there is a continous cycle between ADP converting to ATP which then breaks a bond for energy production and forms ADP which forms ATP again.

    so to anser the first part of your question, ATP is PRIMARLY recycled.

    i am not too sure on what your point is in the second part of the question. glucose does not breakdown and all of a sudden become ATP, it breaks down and is taken by ADP to create ATP.

    have a look into the Krebs cycle/citric acid cycle too, understanding the whole picture will help with the smaller parts. and in this case there is a hell of a lot of reading to do.
    #12
    cliff_vtr
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    RE: glycogen use 2006/07/14 17:47:00 (permalink)
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    yeah good point forgot about cortisol. I guess without insulin cortisol will end up getting released to top up blood sugar levels with glucose from glycogen. Also I think you'd end up going hypo and potentially and feeling like crap.

    EPOC??
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    OoOGazOoO
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    RE: glycogen use 2006/07/14 17:48:50 (permalink)
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    EPOC - excess postexercise oxygen consumption.

    You may hear it referred to as Oxygen Debt.
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    cliff_vtr
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    RE: glycogen use 2006/07/14 17:51:27 (permalink)
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    i am not too sure on what your point is in the second part of the question. glucose does not breakdown and all of a sudden become ATP, it breaks down and is taken by ADP to create ATP.


    Makes sense now

    When blood glucose is directed to a "muscle in need" does it just directly get absorbed as it needs it into the muscle tissue for direct convertion to ATP ? or is there some intermediate pathway, like being converted to glycogen first ?.

    Any good books on this, for someone with not too much knowledge, I mean I find human biology really interesting.

    cheers

    Paul
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    cliff_vtr
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    RE: glycogen use 2006/07/14 17:51:53 (permalink)
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    ORIGINAL: OoOGazOoO

    EPOC - excess postexercise oxygen consumption.

    You may hear it referred to as Oxygen Debt.


    oooo what does that mean ?
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    OoOGazOoO
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    RE: glycogen use 2006/07/14 18:02:20 (permalink)
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    Basically it's a rise in RMR due to previous exercise.

    So for example, you have just done your weight training workout, your metabolism will be elevated for a sustained peroid of time after you finish. Generally, as i understand it, once your finish training there is a time around 2 hours which holds the highest rise in the RMR from the workout, this follows on for the next 24-48 hours but doesnt rise as much as the first 2 hours, if you follow me.

    Following the weight training session what is normally involved in EPOC is that aspects such as the removal of lactic acid from the bloodstream happens, the replenishment of oxygen stores and also the replenishment of the ATP and Cretine Phosphate within the muscle cells.



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    Big D
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    RE: glycogen use 2006/07/14 18:05:27 (permalink)
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    ORIGINAL: cliff_vtr

    i am not too sure on what your point is in the second part of the question. glucose does not breakdown and all of a sudden become ATP, it breaks down and is taken by ADP to create ATP.


    Makes sense now

    When blood glucose is directed to a "muscle in need" does it just directly get absorbed as it needs it into the muscle tissue for direct convertion to ATP ? or is there some intermediate pathway, like being converted to glycogen first ?.

    Any good books on this, for someone with not too much knowledge, I mean I find human biology really interesting.

    cheers

    Paul


    firstly a good book for you would be sports nutrition, by Anita Bean. you have a higher than average knowledge of nutrition so this should be right up your street. nice easy read about some complicated areas!

    secondly, blood glucose in the anaerobic energy system will bypass the oxygen pathways to create ATP much quicker, however as i said this creates the lactic acid build up, which in turn creates fatigue.

    the faster way the body uses ATP is through the ATP-PC (phosphocreatine) system, this is only good in say sprints as it uses the body's stores of phsphocreatine to break it down into phosphate and creatine, then the phosphate is used by ADP to create ATP.

    So...... back to original Q..... glucose is broken down and used straight away by ADP to create ATP in the anaerobic system. wherever it is needed, however it is dependant on which energy system is being used as to how fast ATP is produced for energy.
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