[Ansteorra] Fw: [SCA-Chirurgeon] Rethinking the hydration paradigm

[Sara Glaze]

Finally some evidence to back up my thinking on this subject. :-)

Still, the most important consideration is make sure you drink plenty  
of liquids, preferably non-alcoholic.

Stefan

----- Original Message ----- From: "Galen of Ockham, OP" <Galen.of.Ockham at gmail.com 
 >
To: <SCA-Chirurgeon at yahoogroups.com>
Cc: "Melinda Kaye Brandt" <melinda.kaye.brandt at gmail.com>
Sent: Friday, February 24, 2012 8:22 AM
Subject: [SCA-Chirurgeon] Rethinking the hydration paradigm


> *//*
> How many times have you heard “don’t drink caffeine when you’re
> dehydrated – you’ll pee out more than you take in and make it  
> worse”? I
> know I can’t count the number of times I’ve given that advice. But
> through the years of repeating this advice and observing what people
> actually do, I began to have some nagging doubts. After searching the
> medical research literature, it appears the issue is even simpler  
> than I
> had thought.
>
> If you think of the body as a tank of fluid, it gets filled by  
> drinking
> and loses volume through urine and sweat (for simplicity, I’ll ignore
> other mechanisms of loss). The rate of urine production is  
> automatically
> adjusted to try to keep the tank full – when more fluid comes in, more
> is let out; if not much is coming in, then urine output is slowed.
> Certain substances like caffeine interfere with this control mechanism
> by increasing the rate of urine production. When we exercise or spend
> time in the heat, fluid loss increases through sweat (the tank also  
> gets
> a bit bigger due to extra blood flow to muscles and skin, but again  
> I’ll
> ignore this for the sake of simplicity). The body responds by  
> decreasing
> urine production and letting you know you’re thirsty. You (hopefully)
> respond by drinking.
>
> Now the debate begins: what is the best fluid for rehydration?
>
> The classic argument has been between water and electrolyte fluids
> (sports drinks). I’ve always maintained that water is better, at least
> in the short term. You lose more water than salts when you sweat, and
> you replace the salts you need in your normal diet. The sports drinks
> aren’t absorbed as fast, but include the essential salts and energy
> (carbohydrates). Either one has been long accepted as appropriate for
> rehydration. What has been /verboten/ has been anything containing
> caffeine (or alcohol, but that’s a story for another day). Caffeine is
> indeed a diuretic – a substance that overrides the body’s reflex to
> decrease urine production.So at first look, it makes sense to tell
> people who are trying to fill their tank to avoid something that pulls
> out the stopper.
>
> But let’s think about this some more. If your goal is to fill the  
> tank,
> you can still accomplish that goal even if you have made the drain a
> little bigger. You just need to put more in the input side. So, it
> follows logically that if you would choose to rehydrate with a
> caffeine-containing beverage, you should be able to, but you will have
> to drink more than if you avoided caffeine. Obviously this can’t go on
> indefinitely, as you’ll end up with a net loss, but for the short term
> there shouldn’t be any negative effects. As it turns out, caffeine may
> not open the drain as much as is commonly thought.
>
> A review article in the /Journal of Human Nutrition and Dietetics/  
> from
> 2003 looked at published studies from 1966 through 2002 that deal with
> caffeine and fluid balance in humans. By aggregating the studies from
> this 36 year period they came to the following conclusions:
>
> 1. Large doses of caffeine (above 250 mg) have an acute diuretic  
> action;
>
> 2. Single caffeine doses at the levels found in commonly consumed
> beverages have little or no diuretic action;
>
> 3. Regular caffeine users become habituated to the effects of  
> caffeine,
> diminishing its actions.
>
> To put this into perspective, typical soft drinks contain 20 – 70 mg
> caffeine, tea 40 – 75 mg, and coffee 60 – 200 (though if you get the
> premium grande from your favorite emporium, it could easily be 600  
> mg or
> more). Therefore, most soft drink and tea drinkers are usually  
> ingesting
> less than the 250 mg, the point at which most studies showed the
> diuretic effect starts. /Moderate intake of caffeinated drinks is not
> likely to trigger an increase in urine output, and should not  
> interfere
> with rehydration/. Intake over 250 mg may not have much effect  
> either as
> people who drink that much are usually doing it every day and  
> therefore
> not going to have as strong of an effect as on someone who has been
> abstaining from caffeine.
>
> So what is a reasonable recommendation?
>
> We should continue the mantra of ‘hydrate, hydrate, hydrate’ to ensure
> people are reminded to keep up their fluid intake. What they actually
> choose to drink can largely be left up to their choice based on what
> tastes good to them at the time. From a standpoint of physiology,  
> water
> is the best rehydration solution and is the fastest absorbed into the
> body (but be aware of the /very/ rare complication of hyponatremia ).
> Sports drinks do a good job of rehydration and are flavorful and
> typically taste better than water. But if nothing tastes better to the
> fighter coming off the field than a couple of ice cold Mt Dews, by all
> means, enjoy!
>
> Galen of Ockham, OP
>
> MKA Keith E Brandt, MD, MPH, FAAFP
>
> Maughan, R.J., J. Griffin. Caffeine ingestion and fluid balance: a
> review. J Hum Nutr Dietet, 16, pp 411 – 420. 2003.
>
> -- 
> Magister Galenus Ockhamnesis
> Friar Galen of Ockham, OP
> A Study in Natural Philosophy: http://medievalscience.org
> Chirurgeon's Point: http://chirurgeon.org <http://chirurgeon.org/>
--------
THLord Stefan li Rous    Barony of Bryn Gwlad    Kingdom of Ansteorra
    Mark S. Harris           Austin, Texas          StefanliRous at austin.rr.com
http://www.linkedin.com/in/marksharris
**** See Stefan's Florilegium files at:  http://www.florilegium.org ****