Rowlf

Right then, here's one I'm dying to have an answer to: we all know that tea and coffee cause us to dehydrate, right? We get rid of the liquid volume we have taken in the drink, and then a little more due to the caffeine, right? But wouldn't that mean that theoretically, if we drank nothing but tea and coffee ever, we would eventually die of progressive dehydration? That clearly wouldn't happen, so what gives?

B*ggered if I can figure it out. Any answers?

BTW I had a look at all the posts in the AAS section in reverse order last night. Saw all the people who are giving me advice now getting their first advice. Wow. Hope for me yet....

Borris

so what u mean is, if we drink tea or coffee from now on, we will die eventualy, cause we would be dehydrated? well, your still consuming water when drinking tea and coffee, i wouldnt know the ratio for how much water you would lose per cup though, u have me thinking now lol.

bassline boy

i dont think it drains water out of you at such a rate mate lol.

Pscarb

Caffeine and Dehydration: Myth or Fact?
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Food Insight
NewsBite
July/August 2002

In a recent review article, “Caffeine, Body Fluid-Electrolyte Balance, and Exercise Performance,” published in the June 2002 issue of the International Journal of Sport Nutrition and Exercise Metabolism, researcher Lawrence E. Armstrong, a professor of exercise and environmental physiology at the University of Connecticut, found that caffeine is not the dehydrating demon some people believe. In fact, he concluded that caffeine is no more a diuretic than water.

For years, health and exercise experts have cautioned that consuming caffeine and caffeinated beverages can lead to dehydration. But Armstrong, an avid runner and a well-respected scientist in the field of thermoregulation and human performance, observed evidence to the contrary, so he reviewed the scientific literature to determine whether abstaining from caffeinated beverages was scientifically and physiologically justifiable.

“While there have been several studies done that show caffeine is a mild diuretic, there is no evidence that exercise, when combined with the consumption of caffeine or caffeinated beverages, will result in chronic dehydration, and this is contrary to the advice of most exercise physiologists, physicians and dietitians,” explains Armstrong, who has conducted fluid balance research since 1980.

Supporting Armstrong’s findings is an American Journal of Physiology August 2002 review of the literature on hydration by Dr. Heinz Valtin that cites a University of Nebraska study, which found that caffeinated beverages may be counted toward the daily fluid total.

Armstrong’s analysis of the scientific literature that was focused on moderate amounts of caffeine (equivalent to one to four cups of coffee a day) indicates:

When consuming a caffeinated beverage, the body retains some of the fluid.
Moderate caffeine consumption causes a mild diuresis very similar to that of water (water, when consumed in large volume, increases urine output).
A person who regularly consumes caffeine has a higher tolerance to the diuretic effect.
There is no evidence that consumption of caffeinated beverages causes a fluid-electrolyte imbalance that is detrimental to health or exercise performance.
Although additional research could help confirm these findings, Armstrong’s analysis of the literature is encouraging for regular consumers of caffeinated beverages. The article can be accessed at http://www.humankinetics.com/products/journals/.

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Borris

excellent post paul, thanks for clearing that up.

Karl(Reflex)

Consumption of caffeine is sub 200mg would appear to have little affect on fluid balance:

http://www.blackwell-synergy.com/doi...ournalCode=jhn

Harry

Yep it's the learning and teaching cycle.

Nine Pack

even if caffeine did exert the diuretic effects it is claimed to have, the body has mechanisms to prevent this from going too far. It will produce ADH to stop the syphon effect.
This is why we can stay dry for a show for only a short period of time as the body will always try to return to homeostasis.

Peg

There is a diuretic effect of caffeine and if the water consumption is not adequate that small effect can amount to a very large effect and because of that effect the body will decrease the amount of water excreted from the cells.

Many times a doctor will perscribe the diuretics to remove edema when in fact the diuretics can compound the problem and what is needed is a tidal wave of water consumed.

The human body is amazing. The body will find its water requirement, either by producing a thirst in the mouth to consume water, be it in any form, caffeinated or not, watery foods, and plain jane water. If there is no liquid consumed then it will retain the water it needs and you will go to the bathroom less.

The body will extract the water from the tea and coffee and use it for its biological processes. The caffeine will cause the body to retain some water but you would not dehydrate from drinking only tea and coffee because of the caffeine. If anything you would become more soft and bloated from the water retention to keep the body functioning as best it could with the nutrients given it.

Caffeine is a vasoconstrictor. It's harm, if any, is more in the stress it may cause to the cardiovascular system than it is in causing dehydration.

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Rowlf

Interesting, though, n'est-ce pas? I think I'll let myself have those lovely frothy coffees if I want them then. Lots of lovely calories in the milk, too...

SD

Yes but caffiene only borrows from the future, what comes up must come down. A useless ergogen imho.

SD