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  1. #1
    3 summits of Athens
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    drink-absorption rate is one problem i have

    Hello cycling community,
    i think something in my hydration must be very wrong...I am sweating too much at training,regardless of the weather,sweating in hot weather even at rest,sometimes to a socially embarassing extent. What bothers my riding is the stomach overload with water-or isotonic drinks- that gives me this flatulence feeling. I normally drink 250 ml/15min in summertime and on most of my longer than 2 hours rides i end up kind of fed up with drinking but a little thirsty at the same time! What really happens is a plop in my stomach that obviously doesn't have enough time to propel its fluid before the next sip, resulting in inadequate fluid absorption. So, the situation is being marginally dehydrated (6-7 hours between dark coloured urinations ) and bubbly-stomach on training. Has anything like that troubled you and found a solution,i'd be more than happy to get a tip.
    Thank you medical council!
    May the Force watch over our trace..

  2. #2
    Faster but still slow slowandsteady's Avatar
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    I would see a doctor. For some reason you have delayed gastric emptying or some other issue with absorption.
    "Ride lots." -- Eddy Merckx

  3. #3
    Senior Member Richard Cranium's Avatar
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    Weigh yourself before and after workouts. Log all your drinking. (what and howmuch) Repost with info.

  4. #4
    Faster but still slow slowandsteady's Avatar
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    It could be dozens of things.....see a doctor.

    http://www.sweathelp.org/pdf/Diaphoretic_Diseases.pdf
    "Ride lots." -- Eddy Merckx

  5. #5
    sch
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    Richard has the right idea. No need for a medical exam, 1liter/hour is more than the vast majority of stomachs can empty, the standard maximal/optimal gastric emptying rate is more like 750ml/hr. Intake above this level just fills up the stomach which eventually begins to slosh.

  6. #6
    Faster but still slow slowandsteady's Avatar
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    Richard has the right idea. No need for a medical exam, 1liter/hour is more than the vast majority of stomachs can empty, the standard maximal/optimal gastric emptying rate is more like 750ml/hr. Intake above this level just fills up the stomach which eventually begins to slosh.
    Okay, Dr. Sch.... She has polydipsia without polyuria, and hyperhidrosis associated with dehydration and you think this is okay? 1 liter an hour should easily be emptied from an adult's stomach. The fact that she/he does not have polyuria even with polydipsia shows that there is an issue.
    "Ride lots." -- Eddy Merckx

  7. #7
    Senior Member DannoXYZ's Avatar
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    Yeah, you can easily absorb +1-ltr of water per hour. More like 1.5-2.0ltr is possible. Molality of the solution has an impact, but even at higher concentration, absorbing water is not a limitation, it's absorbing the carbs & nutrients.

    I think implicit in the OP's post is the concern about the sweating-rate. There's absolutely nothing you can do to control sweating. Your body will sweat based upon the exertion-rate that's being exercised. The only thing you can do is to regulate how much you drink to match the rate of sweating. As mentioned, easily done by weighing yourself before & after you can determine a hydrate-rate.

    As for sickening feelings on 2-hour rides, make sure you take in nutrients with the drink. About 250-300 calories/hr is a good target as that's the most you can absorb (still lower than what you burn off). And get sufficient electrolytes as well.

  8. #8
    sch
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    The articles I have read on gastric emptying in athletics give a range between 800 and 1500ml per hour
    or 13 to 25ml/min. The preponderance seem to be well under 1200ml/hour. 1 liter per hour is not exactly polydipsia for a bike rider or endurance runner. It would be for persons at rest at room temperature. From the posters symptoms her gastric emptying is less than her intake but well within the range of variation that researchers have found and gastric distention will occur after 4-6hrs giving the bloat and discomfort alluded to. In the absence of further posts by the original poster providing before and after ride weights and further info, the info provided does not constitute a need for medical evaluation. The real ride duration is not given, but the poster also cross posted in the Long Duration Riding forum so rides presumably exceed the century mark. I think the poster is bumping up against physiologic limits and not necessarily needing medical evaluation. A good trainer perhaps..

  9. #9
    Killing Rabbits
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    My only concern would be the 6-7 hours between urinations part.

    My recommendation would be to abandon your drinking schedule; it’s obviously not working for you. Besides the common recommendation to match fluid intakes and losses, as determined via the aforementioned pre minus post exercise weighing method, is based in logic - not fact. Actual measurements have found no further increase in performance in drinking any more than 400mL/hour of water/sport drink, provided the athlete never becomes more than 3% dehydrated (about 5lbs, this is different than just not drinking until you are 3% dehydrated). The actual reason more than 400mL/hour of sport drink helps is because of carb delivery (a somewhat independent issue, use gels etc). Furthermore, no improvement is found using forced drinking schedules versus at-will drinking provided the 400mL/h mark is met in both groups. Athletes drinking at-will will almost always easily drink the 400mL/h, and then some, without GI distress via the self-titration you are ignoring. The 3% dehydration is reduced or eliminated at the next meal, the ideal time to fully hydrate.

  10. #10
    Senior Member DannoXYZ's Avatar
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    True, the RAAM guys always limited their drinking so that they could have higher concentration of carbs & nutrients. That slowed their water-absorption rate, but increased the carb intake, which was more of a limitation for what their doing anyway. They always ended each day slightly dehydrated.

  11. #11
    Faster but still slow slowandsteady's Avatar
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    My only concern would be the 6-7 hours between urinations part.
    Exactly.
    "Ride lots." -- Eddy Merckx

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