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  1. #1
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    Rennies and Cramping

    During a race a friend of mine cramped. Another cyclists stopped and gave him a Rennie. With indignation he said he cramped and did not have heartburn, The other guy insisted, he took the Rennie and Viola!!!!!! the cramp was gone. Could there be any truth in this, will Rennie (only one ) have the capacity to reduce lactic acid???? This was related to me as true and it is NOT a joke!!!

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    Senior Member demoncyclist's Avatar
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    What exactly is a Rennie???

    DEMON

  3. #3
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    Sorry... I forgot we live in DARKEST Africa!!!!!! I assumed Rennies is a worldwide brand. Rennies is a antacid tablet used to counter excessive stomach acids and also helps for heartburn. Hope this helps.

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  4. #4
    Senior Member keithnordstrom's Avatar
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    hrm what's in it?

  5. #5
    Donating member Richard D's Avatar
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    Quote Originally Posted by keithnordstrom
    hrm what's in it?
    From memory, largely calcium.
    Currently riding an MTB with a split personality - commuting, touring, riding for the sake of riding, on or off road :)

  6. #6
    Jungle lady cbhungry's Avatar
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    I wonder if its calcium carbonate or calcium citrate. I suspect the former, only because it is cheaper. Low calcium causes neuromuscular irritability and cramps but usually the main mechanism of cramping after sustained excercise is from low magnesium or potassium.

    Perhaps the carbonate in the rennie provides a good base buffer but physiologically, one tablet and its absorption should not affect the lactic acid buildup. Bicarbonate, specifically sodium bicarbonate is an alkalising agent and therefore reduces the acidity of the blood (known as a buffering action). However, the clinical research I've seen that showed any improvement in lactate threshold involved loading up with 4grams/day of sodium bicarbonate for six days before it was able to improve VO2max by 9% and the Lactate Threshold raised by 12% .

    Not sure why the rennie would work so fast. Did you or he consume something else with it?
    Last edited by cbhungry; 10-24-03 at 06:26 AM.
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  7. #7
    Senior Member nhorscro's Avatar
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    I thought cramps were predominantly caused by electrolyte loss, not lactic acid build up? Those are two different things I believe. For instance, I can cramp on a long ride (50+ miles) of low intensity (Zone 1 and 2) if it is a hot day. Using a HRM I know I am riding aerobically 95% of the time so lactic acid build up is not an issue.

    The loss of cations such as Na+, Ca++ and Mg++ are what usually cause cramp, and the Ca in an antacid help some people fight off cramp. For instance I know my cramps are caused by Ca loss or deficiency so when I start cramping I take either a Citracal (calcium citrate) or an antacid (calcium carbonate) and I usually get some relief in 5 minutes or less.

    So in this case the calcium has nothing to do with VO2 max, LT or any performance related parameter. It is a simple replacement of divalent cation lost during strenuous exercise that probably induced a lot of sweating.

  8. #8
    Jungle lady cbhungry's Avatar
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    Quote Originally Posted by nhorscro

    So in this case the calcium has nothing to do with VO2 max, LT or any performance related parameter. It is a simple replacement of divalent cation lost during strenuous exercise that probably induced a lot of sweating.
    Although bicarbonate loading at the above loading dose over 6 days or immediate preexcercise dosing does improve the vo2 max, lactate threshold etc. according to many field tests and clinical trials. http://www.asep.com/supplements/cont...tes.cfm?sid=28

    So the one rennie wasn't enough to provide this buffering except a small amount of calcium repletion. His friend must have heard about the bicarbonate studies and attribute the calcium carbonate as a possible base buffer.
    Last edited by cbhungry; 10-28-03 at 07:21 AM.
    Ride forever, work whenever.
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