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    Nutrition. Long Course.

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    Alex R
    **MicroMan World Record Holder**

    Posts : 353
    Join date : 2009-11-02

    Nutrition. Long Course.

    Post by Alex R on Sat Sep 25, 2010 6:16 pm

    I am cross posting from Trnsitions but some may not read there.

    Here is my theory on fueling for long course racing.

    There was a good blurb on theis written by PeePee* called Half Ironman Nutrition for Halfwits that I read just before my first long course race. It was very simple but if anything was probably a tad heavy handed on the carb allocation for my personal circumstances. Anyway, after some trial and error, some reading, a few threads here and some hocus pocus, I settled on the final formula for long course racing.

    Water - 15ml/kilo/hour on hot days 10ml/kilo/hour not so hot days
    Carb - 0.5-0.8g/kilo of body weight per hour
    Salt - 1 gram/hr hot 1 gram/90 minutes not so hot
    Concerntartion of carb in solution 0.5-0.8%

    Now to give an actual physical example of what I mean, lets assume a 75kg person with a 5 hour duration event. The total intake would be-

    Water - 75kg 10-15ml/hr = 75X10-15 = 750ml to 1125ml of water/hr
    Carb - 75kg 0.5-0.8g/hr = 75x 0.5 to 0.8 = 37.5 to 60g carb per hour
    Salt 3 to 5 grams total

    Now, for the concentration of carb in fluid, that works out perfectly with 750ml and 37.5g carb = 5% and 1125 at 60 = 5.3% and at the other ends, the 1125/37.5 is well below 5% which is good and the 60g with 750ml is 8%. All good.

    Things can get pretty technical from there with digestion efficiency V calorie intake and how that changes with intensity but that is not really anything that matters at this stage.
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    Dave Tyno

    Posts : 182
    Join date : 2009-11-02
    Location : Brisbane

    Re: Nutrition. Long Course.

    Post by Dave Tyno on Sun Sep 26, 2010 4:11 am

    The bit I'm starting to think about is people using actual body weight for carb intake.
    Sally worked mine out for the marathon, but she used lean body weight
    So, even though I was sitting at 95 or so, she worked everything out on around 80kgs.
    Even then she scaled down the pre race brekky because it worked out to be a pretty big feed if I went the whole amount.
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    Paul F
    Coach

    Posts : 267
    Join date : 2009-11-02

    Re: Nutrition. Long Course.

    Post by Paul F on Tue Sep 28, 2010 3:30 am

    G'day Alex,

    I was reading some research that suggest that our digestive systems and their ability to digest don't vary according to the size we are.

    So calculations probably shouldn't be based on per kg of body weight, even though that is what we need.

    Look into Glucose/frucose ratios apparently the right ratio greatly increases your ability to absorb.

    In summary , the digestive system of a 100kg man will be the same as a digestive system of a 50kg lady. You just need to calcutate which combo's absorb at the best rates.

    They did some studies on Wellington and work out she could take in up to 600 cals per hour with the right mix of glucose and frucose without frucose at most WE ALL can only absorb aorund 250-350cal per hour without blooding shunting occuring as a result of racing too hard. This is all based on a stable and active digestive system

    Paul
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    Alex R
    **MicroMan World Record Holder**

    Posts : 353
    Join date : 2009-11-02

    Re: Nutrition. Long Course.

    Post by Alex R on Tue Sep 28, 2010 10:13 am

    The ability to digest does not change, that is correct but our basal requirements for fuel do change with mass. As Tyno pointed out above, it is the lean mass we are feeding. This is something I did not mention in that post as it gets confusing. Basal Metabolic Rate increases with weight. You need more fuel to do just live the heavier you are. Once you start adding in activity, the requirement increases and the heavier you are, the more fuel is required.



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    Paul F
    Coach

    Posts : 267
    Join date : 2009-11-02

    Re: Nutrition. Long Course.

    Post by Paul F on Wed Sep 29, 2010 4:14 am

    G'day Alex,

    Good points. it might also be worth considering the intensity you intend on riding at.

    Carb - 75kg 0.5-0.8g/hr = 75x 0.5 to 0.8 = 37.5 to 60g carb per hour

    For example, for someone like Bulldog he is one of the few guys out there that can ride very close to the top of zone 2 with periods of time in zone 3, how he does it I don't know, and he still runs well. This would put his fuelling needs right at the top end ie 60g per hour and he weighs 69kg.

    He would have to be burning a higher % of glycogen compared to fat if you compare his racing to someone who races at the bottom of zone 2, eg Eric, but then Eric weighs 80kg. So in terms of total calorie requirement/burned they would probably end up being somewhat similar.

    It good topic Alex, keeps me thinking how we can best utilize fuel in a race, which I believe is the number 1 limiter in IM's.

    I have a lot more thoughts on this which I put together once I return from tassie.

    WE DONT RUN OUT OF FITNESS WILL ALWAYS RUN OUT OF FUEL!!!!!

    Gotta go.........getting married in couple of hours LOL

    fluro

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