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Gu - does it really help? (Read 295 times)

    drrbradford is correct that studies have shown that even having the taste of sugar in your mouth improve performance, though the exact mechanism may be unclear. Many more studies show that ingesting the calories yields a performance boost, especially over longer duration events.

     

    I take caffeinated Gu for two reasons:

    1) Caloric energy fuels the run.

    2) Caffeine may increase bloodflow (more provable) and dull pain (less provable).

     

    I usually make it a goal to bring four Gus with me for a marathon. I take half of a Gu every 3 miles if I can, which means I am taking it in smaller amounts, but at more regular intervals. This makes it easier for my body to handle the intake, as it's not overwhelmed at any one given time. I try to take liquid near when I take the Gu. I typically alternate water and sports drink just so I'm not going overboard with the amount of sugar intake. Taking half a Gu every 3 miles means that I will only go through four packets of Gu the entire race.

     

    Depending on the caffeine in the Gu this puts me at around 100mg of caffeine intake over the course of the race. I like doing it this way because I start from a baseline zero caffeine and cumulatively add it to my system before reaching a terribly high number. It takes it easier to feel better as the run goes on and I'm less likely to have a heart attack.

     

    There is a strong correlation of caffeine intake being a factor present in a majority of marathon heart attacks. You could argue that this is simply due to almost everyone using caffeine during a marathon. Except that in majority cases of heart attack during a marathon the caffeine intake was found to be greater than 300mg. Others will argue that for best performance you probably want something like 200mg. Just keep in mind that you may be causing your heart rate to jump if you take an excessive amount of caffeine, such as more than 300mg and definitely more than 400mg. Your physiology, how much you ate that day, etc. all also play a large factor in what effect caffeine will have on you.

     

    Anyway, I try to avoid taking much more than 100mg the entire morning. I err on the side of caution.

     

    Getting back to the topic of calories, your body simply isn't made to run 26.2 miles at high efficiency. You store enough calories to handle about 18 miles at an efficient steady burn. Training and your physiology on race day determine some variance from that number. To anyone planning to race at a pace fast enough to steadily burn glycogen I sincerely recommend some kind of calorie intake during any effort that will extend near or over 18 miles. Leisure runners or ultra runners can expect to burn more fat and protein over the course of their event than glycogen-burning brisk marathoners.

     

    If you're taking Gu for any distance less than a 10k you're primarily doing so for caffeine and a few simple sugars. That's not to say it isn't helpful, but understand that you aren't doing it because of an expected calorie problem. I always thought it was funny that high schoolers carb load before a 5k. It shouldn't matter at all unless they've been starving themselves, but I try not to say anything since there are probably a few people on the team who do chronically under-eat.

    Cyberic


      I used to always run without fuel. I'd even run without water. Trying to make my body tougher, more able to go the distance with no help.

       

      Then I decided I'd run a marathon. Not knowing if it would help or not, just from testimonies, I decided I'd race it with fuel. So I had to practice running with fuel, and had to decide which one I liked better.

       

      First long run I ran with gels, was a 2+ hours long run with 4 gels (I bought gels from different companies, trying them out). I am positive I finished my run stronger than I usually did, and I felt better during the rest of the day than usual.

       

      Couple of months later, I ran my first marathon. Took a gel 30 minutes before, another 5 minutes before the start, then one every 40 minutes. The last miles were hard, yes, but my 2 last 5K splits were almost equal to my first 2 5K splits. I don't think I could have done that without fuel.

       

      I believe they help.

      JanaLamb


        I take GUs in marathons, just in case, I don't really know if they helped me or not, I don't really feel any surge of energy, at least they don't hurt, but I hate having sticky fingers.

         

        We have the same experience. I don't really notice if they really help, but I did fine during marathons, that's why I take them.

        Increase Speed and Stamina Blog

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