Is coffee diuretic?

rppa · 14th March 2005, 07:25 AM

Aside from getting into a medical question of interest to me as a voluminous coffee-drinker, this topic also gets into the area of subjective vs. objective evidence which has been raised in many threads in different areas of this forum.

OK, let me start here:

http://bicyclecoffeesystems.com/

This guy is a rabid coffee drinker, and has done a fair job of collecting papers supporting his habit, i.e., supporting the thesis that there is no harmful effect, especially diuretic, from coffee. (Look for the heading "Coffee and Dehydration--Urban Myth" just below the pictures of bicycle-compatible coffee bottles).

These papers make a convincing case that there is no difference in fluid retention from drinking coffee.

Yet I have personal evidence that suggests some connection to dehydration. Some of it is weaker than others, but taken together I feel there's something at odds with the conclusions of those papers, and I want to reconcile it.

Weakest: Coffee affects my singing voice. I'm an amateur singer, no pro but I've sung in some decent choirs and in some stage shows. If I have anything challenging to do (meaning high notes) then coffee seems to have a repeatable negative effect: if I have coffee at all in the hour or so before a performance, I'll choke and cough or otherwise strain myself trying to get the notes. Tea doesn't have this effect (which suggests it's not the caffeine). The best thing is water, especially hot water.

Arguments against this: there is lots of lore in the singing world, some of it scientific, some of it superstition. Singers, like most performers, are a superstitious lot, and one of the biggest enemies of the singing voice is tension. Conceivably, coffee could make me tense just from worrying about it. On the other hand, there could be a physiological connection of coffee -> tension which wouldn't require the "diuretic" explanation.

Stronger: A day of coffee affects my body like a day of not drinking at all. I try to get in 6-8 glasses of water a day. If I do, I wake up feeling good in the morning. If I have little or no liquid during a day, then several physical symptoms will manifest themselves in the morning. From least to most severe (in some cases I get only the first couple, in worst cases all four):

- a lot of coughing in the morning
- (apologies for too much information) strongly-colored urine
- a very dry mouth, to the point where I can barely swallow until I get a little water.
- headaches

I associate all of these symptoms with dehydration from not drinking water. The thing is, I also associate these symptoms with a day in which I have drunk a great deal, almost all of it coffee. This experiment is repeatable.

As I enjoy coffee, I'd be happy to do any controlled experiment anyone wants to suggest. I'll deal with the headaches in the interests of science.

Discussion?

Badly Shaved Monkey · 14th March 2005, 07:59 AM

No objective data, but personal anecdote...

Damn right it's diuretic. I find shortly after coffee I have a full bladder in a way that is untrue if I drink anything else except alcohol. Odd thing I also find is that after coffee I often experience what the medics call "urgency", i.e. get out of my way or there's going to be a wet patch, that is disproportionate to the volume of urine present.

I think I am quite sensitive to caffeine, and my unblinded observations reveal that I get a noticeable hand tremor if I drink too much coffee and it does seem to be able to induce cardiac 'palpitations'.

So, there you go, in some ways more information than you could ever have wanted, yet not enough to answer your question!

Badly Shaved Monkey · 14th March 2005, 08:12 AM

Some facts;

http://coffeefaq.com/caffaq.html

http://www.ncbi.nlm.nih.gov/entrez/q..._uids=12232887

http://www.ncbi.nlm.nih.gov/entrez/q...t_uids=1692926

Ah ha, it's not just me...

http://www.ncbi.nlm.nih.gov/entrez/q...t_uids=2265333

Mojo · 14th March 2005, 08:24 AM

Quote:

Originally posted by Badly Shaved Monkey
Odd thing I also find is that after coffee I often experience what the medics call "urgency", i.e. get out of my way or there's going to be a wet patch, that is disproportionate to the volume of urine present.

It appears that in addition to being a diuretic, caffeine also irritates the bladder, hence the effect described here. Try googling the words caffeine, bladder and irritant.

rppa · 14th March 2005, 08:25 AM

The thing with pregnancy (Coffee FAQ 2.3) is interesting. The first symptom of pregnancy for both of my wife's pregnancies was an aversion to coffee. A friend of ours of Italian heritage (with all that implies about a love for strong coffee) also had a strong aversion to coffee throughout her pregnancy, and immediately after giving birth had such a strong craving that she literally crawled to the nearest vending machine to get a cup.

The fact that there's data on fetal malformation, however weak, must mean that there are some women who do not experience this aversion and continue to consume coffee during pregnancy.

rppa · 14th March 2005, 08:28 AM

Quote:

Originally posted by Mojo
It appears that in addition to being a diuretic...

And yet, and yet...

http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract

Quote:

Investigations comparing caffeine (100-680 mg) to water or placebo seldom found a statistical difference in urine volume. In the 10 studies reviewed, consumption of a CB resulted in 0-84% retention of the initial volume ingested, whereas consumption of water resulted in 0-81% retention. Further, tolerance to caffeine reduces the likelihood that a detrimental fluid-electrolyte imbalance will occur.

Ziggurat · 14th March 2005, 08:30 AM

Quote:

Originally posted by rppa
This guy is a rabid coffee drinker, and has done a fair job of collecting papers supporting his habit, i.e., supporting the thesis that there is no harmful effect, especially diuretic, from coffee. (Look for the heading "Coffee and Dehydration--Urban Myth" just below the pictures of bicycle-compatible coffee bottles).

Here's the quote:

"The logic goes like this: Diuretics cause dehydration. Caffeine is a diuretic. Coffee contains caffeine. Hence drinking coffee causes dehydration. The flaw in this logic is that coffee is NOT mostly caffeine, it is mostly water. The water provides hydration, while the small amount of caffeine has negligible or no effect."

A diuretic causes you to lose more water, but that doesn't produce dehydration unless you don't drink enough water. Period. And caffeine is diuretic, which means coffee is diuretic, period. But it's only in extreme cases (amoebic dyssentry, for example) where you can't solve the problem of dehydration by simply drinking more water, so this is really beside the point to begin with.

Badly Shaved Monkey · 14th March 2005, 08:33 AM

Quote:

Originally posted by Mojo
It appears that in addition to being a diuretic, caffeine also irritates the bladder, hence the effect described here. Try googling the words caffeine, bladder and irritant.

Look at the last link I found;

"increase in detrusor pressure on bladder filling following administration of caffeine"

I assumed that was more likely to be a direct sympathomimetic effect of the caffeine, increasing bladder wall tone for a given volume. But, you suggest another mechanism, but I'm not sure they are contradictory.

An increase in detrusor pressure could be perceived as 'irritation', or it could be the other way round, so that irritation results increased wall turgor.

Badly Shaved Monkey · 14th March 2005, 08:37 AM

Quote:

Originally posted by rppa
And yet, and yet...

http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract

From my quick look at the literature I could see differences in the measures chosen and I think the finding of negative effects could depend on which parameter is measured and and what time. The abstract that showed the effect on detrusor tone was negative for other parameters

Pragmatist · 14th March 2005, 08:42 AM

Quote:

Originally posted by rppa
Coffee affects my singing voice.

I'll second that. I once dropped a scalding hot cup of coffee in my lap and it made me temporarily a soprano!

Phaycops · 14th March 2005, 09:38 AM

Quote:

Originally posted by Ziggurat

A diuretic causes you to lose more water, but that doesn't produce dehydration unless you don't drink enough water. Period. And caffeine is diuretic, which means coffee is diuretic, period. But it's only in extreme cases (amoebic dyssentry, for example) where you can't solve the problem of dehydration by simply drinking more water, so this is really beside the point to begin with.

Wait, I'm confused. So coffee is diuretic just because of the presence of caffiene? What about, like the guy said, the relative amounts of caffiene versus water in a cup of joe? And I'm not sure I understand your point about amoebic dysentery. And I'm also not sure what you mean by "this is really beside the point." What this does your this refer to?

Ziggurat · 14th March 2005, 11:56 AM

Quote:

Originally posted by Phaycops
Wait, I'm confused. So coffee is diuretic just because of the presence of caffiene? What about, like the guy said, the relative amounts of caffiene versus water in a cup of joe?

A diuretic means something that makes you secrete more water from the kidneys (and often the intestines as well). Coffee does that, hence it's a diuretic. That is a somewhat SEPARATE question from whether the net hydration effect of the water in the coffee outbalances the dehydration effects of the caffeine.

Quote:

And I'm not sure I understand your point about amoebic dysentery. And I'm also not sure what you mean by "this is really beside the point." What this does your this refer to?

It's beside the point because, even if you lose more water from drinking coffee than you gain from it (my intuition is that this varies from person to person - it's quite diuretic for me), that really doesn't matter from a dehydration standpoint since you can just drink more water to compensate.

In the case of severe disease (such as dysentery) or poisoning, you're often losing too many electrolytes along with the water, and simply trying to drink more water to compensate doesn't work (you'll end up like that frat kid who died from drinking too much water). But that's irrelevant for coffee, since you're not perturbing your system nearly that much. So the question of whether coffee is good or bad for you (which is really what that guy's kick seems to be) doesn't even depend on whether or not it's a net dehydrator for you. If it is, then just drink more water along with your coffee and it won't hurt you at all (aside from the inconvenience of having to empty your bladder more often).

Phaycops · 14th March 2005, 12:12 PM

Thanks for the clarification.

So is it true that if you're more used to caffiene, it doesn't dehydrate you as much? How does that work? You're just immune to the effects, or your body compensates?

El Greco · 14th March 2005, 12:18 PM

From this page:

Quote:

Tea Drinking and Fluid Balance: A Review

(Maughan 2001 See References)

Tea contains caffeine making it a diuretic. The common view is that caffeine from drinking tea will cause dehydration by increasing urine production leading to lost water needing to be replaced to maintain fluid balance. This actually is not entirely correctâ€¦.It is true that caffeine is a diuretic â€“ it is metabolised in the liver by the p450 system to produce; dimethyl- and monomethyl-xanthines, xanthine and uric acid. (Maughn & Griffin 2001). It is the increase in uric acid (which needs to removed from the body via the kidneys) that causes more urine to be produced. Water is needed to dilute the uric acid to prevent any damage and maintain correct fluid and ion balance. Caffeine may also increase glomerular filtration rate and reduce sodium reabsorption from the renal tubules, thus increasing the amount of water in urine.Studies that have been conducted on the effect of caffeine and tea on fluid balance have produced the following conclusions (Maughn & Griffin 2001);

Large doses of caffeine (above 300 mg/more than 6 cups of tea per day) have an acute diuretic action.
Single caffeine doses at the levels found in commonly consumed beverages have little or no diuretic action (as the potential fluid loss due to the caffeine is replaced by the fluid in the drink itself).
Regular caffeine users become habituated to the effect of caffeine, diminishing its actions.In summary, drinking tea can actually contribute to the recommened fluid intake of 1.5 â€“ 2 litres of fluid per day to maintain good body fluid levels rather than diminish them. Other health benefits include its antioxidant properties (e.g. oxidising LDL (for reducing cardiovascular disease), inhibting cell proliferation and trapping carcinogens (to prevent cancers), and protecting teeth (from acid erosion).

I also seem to recall another study (that I'm too lazy to search for right now) which says that some people's smooth muscles are more sensitive to caffeine and so it may increase their urge to urinate to a greater degree. People with a degree (not necessary pathological) of urinary incontinence will be more sensitive to caffeine. But even for them the diuretic effect can almost disappear if they keep it at 2 mugs of coffee per day.

Darat · 14th March 2005, 12:24 PM

"Large doses of caffeine (above 300 mg/more than 6 cups of tea per day) have an acute diuretic action."

6 cups of tea a day! Goodness knows how much caffeine I'm ingesting a day, I normally have around 12-15 cups of THE Tea everyday. Hmm... did wonder why I'm always rushing to the loo

dissonance · 14th March 2005, 02:56 PM

Quote:

Originally posted by rppa
The thing with pregnancy (Coffee FAQ 2.3) is interesting. The first symptom of pregnancy for both of my wife's pregnancies was an aversion to coffee. A friend of ours of Italian heritage (with all that implies about a love for strong coffee) also had a strong aversion to coffee throughout her pregnancy, and immediately after giving birth had such a strong craving that she literally crawled to the nearest vending machine to get a cup.

I'm currently pregnant, and one of my first symptoms was caffiene aversion. Tea and cola were two things I loved, and when I got pregnant the very thought of them was horrifying.

One of my aunts had the same thing. It doesn't appear to be overwhelmingly common, but it certainly seems to be a not unusual symptom.

My liking of caffiene came back at the start of the third trimester, actually. I've been avoiding it, just because why ingest something that might not be healthy at this point? But the cravings/liking have definitely returned.

AK-Dave · 14th March 2005, 03:32 PM

I just performed a very scientific test of the diuretic effects of caffeine. First, I drank a very large cup of coffee (about 16 ounces). Then, after about an hour with no obvious diuretic effect, I drank a 1 liter Mountian Dew, which contains pretty high levels of caffeine. An hour later, I still did not observe any diuretic effects. I then took a sip of water from the drinking fountian and five minutes later I had to run to the restroom. Based on these observations, I can only conclude that water, not caffeine, is the cause of the diuretic effects.

rppa · 15th March 2005, 07:12 AM

Maybe I'm being stupid, but I still haven't figured out a conclusion from all this. I see there's evidence for bladder irritation by caffeine.

But how about my central question: does coffee cause dehydration? I've got the personal evidence that the water content in coffee does NOT replace the fluid lost from caffeine effects, and then the medical evidence that coffee does not cause net fluid loss.

So which is it? Dammit, I'm thirsty after coffee, despite the claim that it's equivalent to drinking a cup of water. Is there objective scientific evidence to bolster my personal observations? Does coffee cause dehydration or not?

El Greco · 15th March 2005, 07:20 AM

My completely anecdotal conclusion based on a convenient mix of personal observations and gleaned studies is that a concetration of about 25mg of caffeine in 100ml of water will not cause net loss of water to most people, assuming they stay below a total of 300mg of caffeine per day.

Phaycops · 15th March 2005, 07:34 AM

Quote:

Originally posted by rppa
Maybe I'm being stupid, but I still haven't figured out a conclusion from all this. I see there's evidence for bladder irritation by caffeine.

But how about my central question: does coffee cause dehydration? I've got the personal evidence that the water content in coffee does NOT replace the fluid lost from caffeine effects, and then the medical evidence that coffee does not cause net fluid loss.

So which is it? Dammit, I'm thirsty after coffee, despite the claim that it's equivalent to drinking a cup of water. Is there objective scientific evidence to bolster my personal observations? Does coffee cause dehydration or not?

rppa-- I'm not convinced that your observations show that coffee causes dehydration in you. Coffee has lots of other things in it besides caffiene and water. Perhaps your feeling of thirst has something to do with its acidity? If you put sugar in your coffee, does that have any effect on how you feel? A headache the day after may be unrelated, or not related to dehydration, at least. Maybe you're allergic to some trace chemical in coffee. Do better quality coffees make you feel the same way? Etc. etc. etc.

IOW, your personal experiences may not be evidence of what you think they are, and can't confirm or deny the hypothesis that cofee causes you to become dehydrated without ruling out countless other factors.

In my personal experience, coffee used to cause me great....gastrointestinal distress, let's just say. Then, around late high school sometime (yes, I started early!), I switched over to "gourmet" coffee from Folger's. What a difference! I could get through my whole day without feeling like my stomach was being twisted and burned and stabbed with tiny little knives all at the same time. I wasn't running to the bathroom as soon as I got to school. In this case, it would appear that my reaction to the coffee had nothing to do with either fluid content or caffiene, but rather something else in the coffee. I don't think this is proof one way or the other, but it's just a story related to cofee for me to tell so I can fit in

rppa · 15th March 2005, 07:55 AM

rppa-- I'm not convinced that your observations show that coffee causes dehydration in you.

Nor am I. I note that the symptoms are the same, but I don't believe it's the caffeine, as tea does not have seem to any such effect. Or at least so my memory tells me. In this forum, I guess I need not point out the impressions and memories can be surprisingly unreliable. See Randi's recent column on the unreliability of memory.

Coffee has lots of other things in it besides caffiene and water. Perhaps your feeling of thirst has something to do with its acidity?

Thirst is only one of the symptoms. See the opening post for the others.

Now this gets really subjective, but I believe I can tell the difference between a dehydration headache (which actually is a new thing for me, just in the last few years) and a caffeine-withdrawal headache (something that used to hit me a lot on weekends, as I drink a lot of coffee on weekdays and then would tend not to have any till quite late, if at all, on Saturday). My habits haven't changed but I no longer seem to be bothered by caffeine withdrawal, even after an abrupt shift in caffeine intake.

If you put sugar in your coffee, does that have any effect on how you feel?

I wouldn't know, as I consider sugar in coffee a crime against nature. Anything for science, though...

A headache the day after may be unrelated, or not related to dehydration, at least.

It might be if it wasn't also coincident with all of the other symptoms typical (for me) of dehydration. See opening post.

Maybe you're allergic to some trace chemical in coffee. Do better quality coffees make you feel the same way? Etc. etc. etc.

Off the top of my head? Yes, I think so.

But this gets dangerously anecdotal. Time for a controlled experiment, I think.

IOW, your personal experiences may not be evidence of what you think they are, and can't confirm or deny the hypothesis that cofee causes you to become dehydrated without ruling out countless other factors.

Sure. Hence my opening this thread instead of just declaring "coffee dehydrates me". Personal experience seems to suggest that, but it's not a controlled experiment.

Got a suggestion for an experimental protocol? Anyone else want to drink some java for the cause?

In my personal experience, coffee used to cause me great....gastrointestinal distress, let's just say. Then, around late high school sometime (yes, I started early!), I switched over to "gourmet" coffee from Folger's.

I'm not real snooty about coffee, but most of my coffee these days is better quality (I'll spend $8 for a pound, sometimes, but it bugs me to spend $10 or more). And after coming back from Italy last summer, my wife and I have taken to frequently making coffee in the Italian style, using an Italian stovetop percolator. That's strong stuff.

Phaycops · 15th March 2005, 08:10 AM

Quote:

Originally posted by rppa Got a suggestion for an experimental protocol? Anyone else want to drink some java for the cause? [/b]

Ooh, this could be fun!

First, though, as to your other symptoms, I get those kinds of symptoms (cough, thirst) in the morning during the winter when the air in my house is much dryer. I also tend to just feel really crappy in the morning anyway

Ok, experiment. We don't want to deliberately dehydrate anyone, because that may be unsafe.

How about something like, for several days drink x amount of coffee, then for several days drink 2x amount of coffee, and rate your symptoms each morning? Does anyone else want to help? I drink two cups of coffee every morning, but I'm sure I can manage to drink an extra two cups when I get home, you know, for science

El Greco · 15th March 2005, 08:23 AM

If I may offer some hints for a protocol design, I'd suggest a closely monitored diet during the days of the experiment since total carbohydrate and sodium intake can greatly affect the hydration state of the body. So does exercise. Caffeine should be calculated from all sources besides coffee (eg chocolate). Urine should be collected in appopriate containers and measured. Water intake should be a constant.

Phaycops · 15th March 2005, 08:32 AM

Quote:

Originally posted by El Greco
If I may offer some hints for a protocol design, I'd suggest a closely monitored diet during the days of the experiment since total carbohydrate and sodium intake can greatly affect the hydration state of the body. So does exercise. Caffeine should be calculated from all sources besides coffee (eg chocolate). Urine should be collected in appopriate containers and measured. Water intake should be a constant.

I agree with everything you said, but I thought the idea was to evaluate, to the extent possible, whether rppa's symptoms are caused by coffee.

Let's start over. What are we trying to prove?

El Greco · 15th March 2005, 08:44 AM

Quote:

Originally posted by Phaycops
Let's start over. What are we trying to prove?

I suppose whether rppa's habitual coffee drinking combined with his habitual fluid drinking affects one's hydration state ? That was the title of the thread anyway. Besides, why else would he ask for other participants ? What help would they be of if he only wanted to test his strictly subjective symptoms ?

Phaycops · 15th March 2005, 08:57 AM

Ok....

Hypothesis: drinking coffee makes you dehydrated.

Now, how can we investigate this hypothesis considering the following facts:
1. We can't afford laboratory services.
2. Nobody wants to bottle up their urine every day, anyway.
3. We're all in different areas.
4. We'll presumably be making our own coffee, so we'll know if it's decaf or regular, as well as what we put in it.
5. We may not all be able to drink the same kind of coffee.
6. We have different coffee makers, and preferneces as far as how strong we make the coffee.
7. Many of the indicators of dehdration or increased urine production are very subjective -- for example, I tend to urinate frequently anyway, so a small increase may not be noticeable.

This is why I suggested we can measure our subjective responses to more or less coffee. Volunteers would be good because even though I personally don't notice an increase or decrease in certain symptoms with coffee usage, maybe I would if I tried. I dunno. It's not perfect, so any suggestions?

El Greco · 15th March 2005, 09:04 AM

Quote:

Originally posted by Phaycops
Hypothesis: drinking coffee makes you dehydrated.

I would rephrase this as "rppa's usual coffee and fluid intake may cause a net water loss". We cannot say that any coffee drinking can cause dehydration. For example I'm pretty sure that even if one drinks 4-5 mugs of coffee each day, one extra glass of water after each mug would be enough to prevent water loss.

rppa · 15th March 2005, 09:08 AM

Quote:

Originally posted by El Greco
I suppose whether rppa's habitual coffee drinking combined with his habitual fluid drinking affects one's hydration state ? That was the title of the thread anyway. Besides, why else would he ask for other participants ? What help would they be of if he only wanted to test his strictly subjective symptoms ?

What he said, but about more than my own personal habits.

I want to pin down the connection (or lack of one) between coffee and hydration. I'd rather do it with more subjects than just myself.

We have a claim in at least one cited source that the water content of coffee balances the diuretic effect. I think that's flat wrong.

As a rough guess, I consume somewhere in excess of 36 ounces (1.1 liter) of coffee per day, almost always caffeinated. This may be qualititatively different from drinking 2-3 cups, caffeinated or not. This needs to be tested.

Edited to add: On reflection, 36 oz is probably a significant underestimate for those days I wake up feeling dehydrated.

I *suspect* that it's not the caffeine content of coffee, and that decaf would have much the same effect on me. But this needs to be tested as well.

14th March 2005, 07:25 AM	#1
rppa Muse Join Date: May 2004 Posts: 794	Is coffee diuretic? Aside from getting into a medical question of interest to me as a voluminous coffee-drinker, this topic also gets into the area of subjective vs. objective evidence which has been raised in many threads in different areas of this forum. OK, let me start here: http://bicyclecoffeesystems.com/ This guy is a rabid coffee drinker, and has done a fair job of collecting papers supporting his habit, i.e., supporting the thesis that there is no harmful effect, especially diuretic, from coffee. (Look for the heading "Coffee and Dehydration--Urban Myth" just below the pictures of bicycle-compatible coffee bottles). These papers make a convincing case that there is no difference in fluid retention from drinking coffee. Yet I have personal evidence that suggests some connection to dehydration. Some of it is weaker than others, but taken together I feel there's something at odds with the conclusions of those papers, and I want to reconcile it. Weakest: Coffee affects my singing voice. I'm an amateur singer, no pro but I've sung in some decent choirs and in some stage shows. If I have anything challenging to do (meaning high notes) then coffee seems to have a repeatable negative effect: if I have coffee at all in the hour or so before a performance, I'll choke and cough or otherwise strain myself trying to get the notes. Tea doesn't have this effect (which suggests it's not the caffeine). The best thing is water, especially hot water. Arguments against this: there is lots of lore in the singing world, some of it scientific, some of it superstition. Singers, like most performers, are a superstitious lot, and one of the biggest enemies of the singing voice is tension. Conceivably, coffee could make me tense just from worrying about it. On the other hand, there could be a physiological connection of coffee -> tension which wouldn't require the "diuretic" explanation. Stronger: A day of coffee affects my body like a day of not drinking at all. I try to get in 6-8 glasses of water a day. If I do, I wake up feeling good in the morning. If I have little or no liquid during a day, then several physical symptoms will manifest themselves in the morning. From least to most severe (in some cases I get only the first couple, in worst cases all four): - a lot of coughing in the morning - (apologies for too much information) strongly-colored urine - a very dry mouth, to the point where I can barely swallow until I get a little water. - headaches I associate all of these symptoms with dehydration from not drinking water. The thing is, I also associate these symptoms with a day in which I have drunk a great deal, almost all of it coffee. This experiment is repeatable. As I enjoy coffee, I'd be happy to do any controlled experiment anyone wants to suggest. I'll deal with the headaches in the interests of science. Discussion?
rppa Muse Join Date: May 2004 Posts: 794

14th March 2005, 07:59 AM	#2
Badly Shaved Monkey Anti-homeopathy illuminati member Join Date: Feb 2004 Location: Outside a banana and far from a razor Posts: 5,262	No objective data, but personal anecdote... Damn right it's diuretic. I find shortly after coffee I have a full bladder in a way that is untrue if I drink anything else except alcohol. Odd thing I also find is that after coffee I often experience what the medics call "urgency", i.e. get out of my way or there's going to be a wet patch, that is disproportionate to the volume of urine present. I think I am quite sensitive to caffeine, and my unblinded observations reveal that I get a noticeable hand tremor if I drink too much coffee and it does seem to be able to induce cardiac 'palpitations'. So, there you go, in some ways more information than you could ever have wanted, yet not enough to answer your question!
	__________________ "i'm frankly surprised homeopathy does as well as placebo" Anonymous homeopath. "Alas, to wear the mantle of Galileo it is not enough that you be persecuted by an unkind establishment; you must also be right." (Robert Park) Is the pen is mightier than the sword? Its effectiveness as a weapon is certainly enhanced if it is sharpened properly and poked in the eye of your opponent.

14th March 2005, 08:12 AM	#3
Badly Shaved Monkey Anti-homeopathy illuminati member Join Date: Feb 2004 Location: Outside a banana and far from a razor Posts: 5,262	Some facts; http://coffeefaq.com/caffaq.html http://www.ncbi.nlm.nih.gov/entrez/q..._uids=12232887 http://www.ncbi.nlm.nih.gov/entrez/q...t_uids=1692926 Ah ha, it's not just me... http://www.ncbi.nlm.nih.gov/entrez/q...t_uids=2265333
	__________________ "i'm frankly surprised homeopathy does as well as placebo" Anonymous homeopath. "Alas, to wear the mantle of Galileo it is not enough that you be persecuted by an unkind establishment; you must also be right." (Robert Park) Is the pen is mightier than the sword? Its effectiveness as a weapon is certainly enhanced if it is sharpened properly and poked in the eye of your opponent.

14th March 2005, 08:24 AM	#4
Mojo Mostly harmless Join Date: Jul 2004 Location: Nor Flanden Posts: 22,089	Quote: Originally posted by Badly Shaved Monkey Odd thing I also find is that after coffee I often experience what the medics call "urgency", i.e. get out of my way or there's going to be a wet patch, that is disproportionate to the volume of urine present. It appears that in addition to being a diuretic, caffeine also irritates the bladder, hence the effect described here. Try googling the words caffeine, bladder and irritant.
	__________________ "You got to use your brain." - McKinley Morganfield "The poor mystic homeopaths feel like petted house-cats thrown at high flood on the breaking ice." - Leon Trotsky

14th March 2005, 08:25 AM	#5
rppa Muse Join Date: May 2004 Posts: 794	The thing with pregnancy (Coffee FAQ 2.3) is interesting. The first symptom of pregnancy for both of my wife's pregnancies was an aversion to coffee. A friend of ours of Italian heritage (with all that implies about a love for strong coffee) also had a strong aversion to coffee throughout her pregnancy, and immediately after giving birth had such a strong craving that she literally crawled to the nearest vending machine to get a cup. The fact that there's data on fetal malformation, however weak, must mean that there are some women who do not experience this aversion and continue to consume coffee during pregnancy.
rppa Muse Join Date: May 2004 Posts: 794

14th March 2005, 08:28 AM	#6
rppa Muse Join Date: May 2004 Posts: 794	Quote: Originally posted by Mojo It appears that in addition to being a diuretic... And yet, and yet... http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract Quote: Investigations comparing caffeine (100-680 mg) to water or placebo seldom found a statistical difference in urine volume. In the 10 studies reviewed, consumption of a CB resulted in 0-84% retention of the initial volume ingested, whereas consumption of water resulted in 0-81% retention. Further, tolerance to caffeine reduces the likelihood that a detrimental fluid-electrolyte imbalance will occur.
rppa Muse Join Date: May 2004 Posts: 794

14th March 2005, 08:30 AM	#7
Ziggurat Penultimate Amazing Join Date: Jun 2003 Posts: 26,189	Re: Is coffee diuretic? Quote: Originally posted by rppa This guy is a rabid coffee drinker, and has done a fair job of collecting papers supporting his habit, i.e., supporting the thesis that there is no harmful effect, especially diuretic, from coffee. (Look for the heading "Coffee and Dehydration--Urban Myth" just below the pictures of bicycle-compatible coffee bottles). Here's the quote: "The logic goes like this: Diuretics cause dehydration. Caffeine is a diuretic. Coffee contains caffeine. Hence drinking coffee causes dehydration. The flaw in this logic is that coffee is NOT mostly caffeine, it is mostly water. The water provides hydration, while the small amount of caffeine has negligible or no effect." A diuretic causes you to lose more water, but that doesn't produce dehydration unless you don't drink enough water. Period. And caffeine is diuretic, which means coffee is diuretic, period. But it's only in extreme cases (amoebic dyssentry, for example) where you can't solve the problem of dehydration by simply drinking more water, so this is really beside the point to begin with.
	__________________ "As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law

14th March 2005, 08:33 AM	#8
Badly Shaved Monkey Anti-homeopathy illuminati member Join Date: Feb 2004 Location: Outside a banana and far from a razor Posts: 5,262	Quote: Originally posted by Mojo It appears that in addition to being a diuretic, caffeine also irritates the bladder, hence the effect described here. Try googling the words caffeine, bladder and irritant. Look at the last link I found; "increase in detrusor pressure on bladder filling following administration of caffeine" I assumed that was more likely to be a direct sympathomimetic effect of the caffeine, increasing bladder wall tone for a given volume. But, you suggest another mechanism, but I'm not sure they are contradictory. An increase in detrusor pressure could be perceived as 'irritation', or it could be the other way round, so that irritation results increased wall turgor.
	__________________ "i'm frankly surprised homeopathy does as well as placebo" Anonymous homeopath. "Alas, to wear the mantle of Galileo it is not enough that you be persecuted by an unkind establishment; you must also be right." (Robert Park) Is the pen is mightier than the sword? Its effectiveness as a weapon is certainly enhanced if it is sharpened properly and poked in the eye of your opponent.

14th March 2005, 08:37 AM	#9
Badly Shaved Monkey Anti-homeopathy illuminati member Join Date: Feb 2004 Location: Outside a banana and far from a razor Posts: 5,262	Quote: Originally posted by rppa And yet, and yet... http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract From my quick look at the literature I could see differences in the measures chosen and I think the finding of negative effects could depend on which parameter is measured and and what time. The abstract that showed the effect on detrusor tone was negative for other parameters
	__________________ "i'm frankly surprised homeopathy does as well as placebo" Anonymous homeopath. "Alas, to wear the mantle of Galileo it is not enough that you be persecuted by an unkind establishment; you must also be right." (Robert Park) Is the pen is mightier than the sword? Its effectiveness as a weapon is certainly enhanced if it is sharpened properly and poked in the eye of your opponent.

14th March 2005, 08:42 AM	#10
Pragmatist Graduate Poster Join Date: May 2004 Posts: 1,529	Re: Is coffee diuretic? Quote: Originally posted by rppa Coffee affects my singing voice. I'll second that. I once dropped a scalding hot cup of coffee in my lap and it made me temporarily a soprano!

14th March 2005, 09:38 AM	#11
Phaycops Guest Join Date: Nov 2002 Location: Upstate NY Posts: 517	Re: Re: Is coffee diuretic? Quote: Originally posted by Ziggurat A diuretic causes you to lose more water, but that doesn't produce dehydration unless you don't drink enough water. Period. And caffeine is diuretic, which means coffee is diuretic, period. But it's only in extreme cases (amoebic dyssentry, for example) where you can't solve the problem of dehydration by simply drinking more water, so this is really beside the point to begin with. Wait, I'm confused. So coffee is diuretic just because of the presence of caffiene? What about, like the guy said, the relative amounts of caffiene versus water in a cup of joe? And I'm not sure I understand your point about amoebic dysentery. And I'm also not sure what you mean by "this is really beside the point." What this does your this refer to?

14th March 2005, 11:56 AM	#12
Ziggurat Penultimate Amazing Join Date: Jun 2003 Posts: 26,189	Re: Re: Re: Is coffee diuretic? Quote: Originally posted by Phaycops Wait, I'm confused. So coffee is diuretic just because of the presence of caffiene? What about, like the guy said, the relative amounts of caffiene versus water in a cup of joe? A diuretic means something that makes you secrete more water from the kidneys (and often the intestines as well). Coffee does that, hence it's a diuretic. That is a somewhat SEPARATE question from whether the net hydration effect of the water in the coffee outbalances the dehydration effects of the caffeine. Quote: And I'm not sure I understand your point about amoebic dysentery. And I'm also not sure what you mean by "this is really beside the point." What this does your this refer to? It's beside the point because, even if you lose more water from drinking coffee than you gain from it (my intuition is that this varies from person to person - it's quite diuretic for me), that really doesn't matter from a dehydration standpoint since you can just drink more water to compensate. In the case of severe disease (such as dysentery) or poisoning, you're often losing too many electrolytes along with the water, and simply trying to drink more water to compensate doesn't work (you'll end up like that frat kid who died from drinking too much water). But that's irrelevant for coffee, since you're not perturbing your system nearly that much. So the question of whether coffee is good or bad for you (which is really what that guy's kick seems to be) doesn't even depend on whether or not it's a net dehydrator for you. If it is, then just drink more water along with your coffee and it won't hurt you at all (aside from the inconvenience of having to empty your bladder more often).
	__________________ "As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law

14th March 2005, 12:12 PM	#13
Phaycops Guest Join Date: Nov 2002 Location: Upstate NY Posts: 517	Thanks for the clarification. So is it true that if you're more used to caffiene, it doesn't dehydrate you as much? How does that work? You're just immune to the effects, or your body compensates?

14th March 2005, 12:18 PM	#14
El Greco Summer worshipper Join Date: Nov 2003 Location: Παρά θιν'αλός Posts: 14,271	From this page: Quote: Tea Drinking and Fluid Balance: A Review (Maughan 2001 See References) Tea contains caffeine making it a diuretic. The common view is that caffeine from drinking tea will cause dehydration by increasing urine production leading to lost water needing to be replaced to maintain fluid balance. This actually is not entirely correctâ€¦.It is true that caffeine is a diuretic â€“ it is metabolised in the liver by the p450 system to produce; dimethyl- and monomethyl-xanthines, xanthine and uric acid. (Maughn & Griffin 2001). It is the increase in uric acid (which needs to removed from the body via the kidneys) that causes more urine to be produced. Water is needed to dilute the uric acid to prevent any damage and maintain correct fluid and ion balance. Caffeine may also increase glomerular filtration rate and reduce sodium reabsorption from the renal tubules, thus increasing the amount of water in urine.Studies that have been conducted on the effect of caffeine and tea on fluid balance have produced the following conclusions (Maughn & Griffin 2001); Large doses of caffeine (above 300 mg/more than 6 cups of tea per day) have an acute diuretic action. Single caffeine doses at the levels found in commonly consumed beverages have little or no diuretic action (as the potential fluid loss due to the caffeine is replaced by the fluid in the drink itself). Regular caffeine users become habituated to the effect of caffeine, diminishing its actions.In summary, drinking tea can actually contribute to the recommened fluid intake of 1.5 â€“ 2 litres of fluid per day to maintain good body fluid levels rather than diminish them. Other health benefits include its antioxidant properties (e.g. oxidising LDL (for reducing cardiovascular disease), inhibting cell proliferation and trapping carcinogens (to prevent cancers), and protecting teeth (from acid erosion). I also seem to recall another study (that I'm too lazy to search for right now) which says that some people's smooth muscles are more sensitive to caffeine and so it may increase their urge to urinate to a greater degree. People with a degree (not necessary pathological) of urinary incontinence will be more sensitive to caffeine. But even for them the diuretic effect can almost disappear if they keep it at 2 mugs of coffee per day.
	__________________ "Robbing a bank is no crime compared to owning one" - Bertolt Brecht "Let it go and come to bed already, El Greco" - MoeFaux

14th March 2005, 12:24 PM	#15
Darat Lackey Administrator / JREF Forum Liaison Join Date: Aug 2001 Location: South East, UK Posts: 64,770	"Large doses of caffeine (above 300 mg/more than 6 cups of tea per day) have an acute diuretic action." 6 cups of tea a day! Goodness knows how much caffeine I'm ingesting a day, I normally have around 12-15 cups of THE Tea everyday. Hmm... did wonder why I'm always rushing to the loo
	__________________ If it were all so simple! If only there were evil people somewhere insidiously committing evil deeds, and it were necessary only to separate them from the rest of us and destroy them. But the line dividing good and evil cuts through the heart of every human being. And who is willing to destroy a piece of his own heart? - Aleksandr Solzhenitsyn 1918-2008

14th March 2005, 02:56 PM	#16
dissonance Critical Thinker Join Date: Mar 2003 Posts: 274	Quote: Originally posted by rppa The thing with pregnancy (Coffee FAQ 2.3) is interesting. The first symptom of pregnancy for both of my wife's pregnancies was an aversion to coffee. A friend of ours of Italian heritage (with all that implies about a love for strong coffee) also had a strong aversion to coffee throughout her pregnancy, and immediately after giving birth had such a strong craving that she literally crawled to the nearest vending machine to get a cup. I'm currently pregnant, and one of my first symptoms was caffiene aversion. Tea and cola were two things I loved, and when I got pregnant the very thought of them was horrifying. One of my aunts had the same thing. It doesn't appear to be overwhelmingly common, but it certainly seems to be a not unusual symptom. My liking of caffiene came back at the start of the third trimester, actually. I've been avoiding it, just because why ingest something that might not be healthy at this point? But the cravings/liking have definitely returned.

14th March 2005, 03:32 PM	#17
AK-Dave Muse Join Date: Oct 2003 Location: Alaska Posts: 576	I just performed a very scientific test of the diuretic effects of caffeine. First, I drank a very large cup of coffee (about 16 ounces). Then, after about an hour with no obvious diuretic effect, I drank a 1 liter Mountian Dew, which contains pretty high levels of caffeine. An hour later, I still did not observe any diuretic effects. I then took a sip of water from the drinking fountian and five minutes later I had to run to the restroom. Based on these observations, I can only conclude that water, not caffeine, is the cause of the diuretic effects.
	__________________ All those who fight monsters inevitably become one.

15th March 2005, 07:12 AM	#18
rppa Muse Join Date: May 2004 Posts: 794	Maybe I'm being stupid, but I still haven't figured out a conclusion from all this. I see there's evidence for bladder irritation by caffeine. But how about my central question: does coffee cause dehydration? I've got the personal evidence that the water content in coffee does NOT replace the fluid lost from caffeine effects, and then the medical evidence that coffee does not cause net fluid loss. So which is it? Dammit, I'm thirsty after coffee, despite the claim that it's equivalent to drinking a cup of water. Is there objective scientific evidence to bolster my personal observations? Does coffee cause dehydration or not?
rppa Muse Join Date: May 2004 Posts: 794

15th March 2005, 07:20 AM	#19
El Greco Summer worshipper Join Date: Nov 2003 Location: Παρά θιν'αλός Posts: 14,271	My completely anecdotal conclusion based on a convenient mix of personal observations and gleaned studies is that a concetration of about 25mg of caffeine in 100ml of water will not cause net loss of water to most people, assuming they stay below a total of 300mg of caffeine per day.
	__________________ "Robbing a bank is no crime compared to owning one" - Bertolt Brecht "Let it go and come to bed already, El Greco" - MoeFaux

15th March 2005, 07:34 AM	#20
Phaycops Guest Join Date: Nov 2002 Location: Upstate NY Posts: 517	Quote: Originally posted by rppa Maybe I'm being stupid, but I still haven't figured out a conclusion from all this. I see there's evidence for bladder irritation by caffeine. But how about my central question: does coffee cause dehydration? I've got the personal evidence that the water content in coffee does NOT replace the fluid lost from caffeine effects, and then the medical evidence that coffee does not cause net fluid loss. So which is it? Dammit, I'm thirsty after coffee, despite the claim that it's equivalent to drinking a cup of water. Is there objective scientific evidence to bolster my personal observations? Does coffee cause dehydration or not? rppa-- I'm not convinced that your observations show that coffee causes dehydration in you. Coffee has lots of other things in it besides caffiene and water. Perhaps your feeling of thirst has something to do with its acidity? If you put sugar in your coffee, does that have any effect on how you feel? A headache the day after may be unrelated, or not related to dehydration, at least. Maybe you're allergic to some trace chemical in coffee. Do better quality coffees make you feel the same way? Etc. etc. etc. IOW, your personal experiences may not be evidence of what you think they are, and can't confirm or deny the hypothesis that cofee causes you to become dehydrated without ruling out countless other factors. In my personal experience, coffee used to cause me great....gastrointestinal distress, let's just say. Then, around late high school sometime (yes, I started early!), I switched over to "gourmet" coffee from Folger's. What a difference! I could get through my whole day without feeling like my stomach was being twisted and burned and stabbed with tiny little knives all at the same time. I wasn't running to the bathroom as soon as I got to school. In this case, it would appear that my reaction to the coffee had nothing to do with either fluid content or caffiene, but rather something else in the coffee. I don't think this is proof one way or the other, but it's just a story related to cofee for me to tell so I can fit in

15th March 2005, 07:55 AM	#21
rppa Muse Join Date: May 2004 Posts: 794	rppa-- I'm not convinced that your observations show that coffee causes dehydration in you. Nor am I. I note that the symptoms are the same, but I don't believe it's the caffeine, as tea does not have seem to any such effect. Or at least so my memory tells me. In this forum, I guess I need not point out the impressions and memories can be surprisingly unreliable. See Randi's recent column on the unreliability of memory. Coffee has lots of other things in it besides caffiene and water. Perhaps your feeling of thirst has something to do with its acidity? Thirst is only one of the symptoms. See the opening post for the others. Now this gets really subjective, but I believe I can tell the difference between a dehydration headache (which actually is a new thing for me, just in the last few years) and a caffeine-withdrawal headache (something that used to hit me a lot on weekends, as I drink a lot of coffee on weekdays and then would tend not to have any till quite late, if at all, on Saturday). My habits haven't changed but I no longer seem to be bothered by caffeine withdrawal, even after an abrupt shift in caffeine intake. If you put sugar in your coffee, does that have any effect on how you feel? I wouldn't know, as I consider sugar in coffee a crime against nature. Anything for science, though... A headache the day after may be unrelated, or not related to dehydration, at least. It might be if it wasn't also coincident with all of the other symptoms typical (for me) of dehydration. See opening post. Maybe you're allergic to some trace chemical in coffee. Do better quality coffees make you feel the same way? Etc. etc. etc. Off the top of my head? Yes, I think so. But this gets dangerously anecdotal. Time for a controlled experiment, I think. IOW, your personal experiences may not be evidence of what you think they are, and can't confirm or deny the hypothesis that cofee causes you to become dehydrated without ruling out countless other factors. Sure. Hence my opening this thread instead of just declaring "coffee dehydrates me". Personal experience seems to suggest that, but it's not a controlled experiment. Got a suggestion for an experimental protocol? Anyone else want to drink some java for the cause? In my personal experience, coffee used to cause me great....gastrointestinal distress, let's just say. Then, around late high school sometime (yes, I started early!), I switched over to "gourmet" coffee from Folger's. I'm not real snooty about coffee, but most of my coffee these days is better quality (I'll spend $8 for a pound, sometimes, but it bugs me to spend $10 or more). And after coming back from Italy last summer, my wife and I have taken to frequently making coffee in the Italian style, using an Italian stovetop percolator. That's strong stuff.
rppa Muse Join Date: May 2004 Posts: 794

15th March 2005, 08:10 AM	#22
Phaycops Guest Join Date: Nov 2002 Location: Upstate NY Posts: 517	Quote: Originally posted by rppa Got a suggestion for an experimental protocol? Anyone else want to drink some java for the cause? [/b] Ooh, this could be fun! First, though, as to your other symptoms, I get those kinds of symptoms (cough, thirst) in the morning during the winter when the air in my house is much dryer. I also tend to just feel really crappy in the morning anyway Ok, experiment. We don't want to deliberately dehydrate anyone, because that may be unsafe. How about something like, for several days drink x amount of coffee, then for several days drink 2x amount of coffee, and rate your symptoms each morning? Does anyone else want to help? I drink two cups of coffee every morning, but I'm sure I can manage to drink an extra two cups when I get home, you know, for science

15th March 2005, 08:23 AM	#23
El Greco Summer worshipper Join Date: Nov 2003 Location: Παρά θιν'αλός Posts: 14,271	If I may offer some hints for a protocol design, I'd suggest a closely monitored diet during the days of the experiment since total carbohydrate and sodium intake can greatly affect the hydration state of the body. So does exercise. Caffeine should be calculated from all sources besides coffee (eg chocolate). Urine should be collected in appopriate containers and measured. Water intake should be a constant.
	__________________ "Robbing a bank is no crime compared to owning one" - Bertolt Brecht "Let it go and come to bed already, El Greco" - MoeFaux

15th March 2005, 08:32 AM	#24
Phaycops Guest Join Date: Nov 2002 Location: Upstate NY Posts: 517	Quote: Originally posted by El Greco If I may offer some hints for a protocol design, I'd suggest a closely monitored diet during the days of the experiment since total carbohydrate and sodium intake can greatly affect the hydration state of the body. So does exercise. Caffeine should be calculated from all sources besides coffee (eg chocolate). Urine should be collected in appopriate containers and measured. Water intake should be a constant. I agree with everything you said, but I thought the idea was to evaluate, to the extent possible, whether rppa's symptoms are caused by coffee. Let's start over. What are we trying to prove?

15th March 2005, 08:44 AM	#25
El Greco Summer worshipper Join Date: Nov 2003 Location: Παρά θιν'αλός Posts: 14,271	Quote: Originally posted by Phaycops Let's start over. What are we trying to prove? I suppose whether rppa's habitual coffee drinking combined with his habitual fluid drinking affects one's hydration state ? That was the title of the thread anyway. Besides, why else would he ask for other participants ? What help would they be of if he only wanted to test his strictly subjective symptoms ?
	__________________ "Robbing a bank is no crime compared to owning one" - Bertolt Brecht "Let it go and come to bed already, El Greco" - MoeFaux

15th March 2005, 08:57 AM	#26
Phaycops Guest Join Date: Nov 2002 Location: Upstate NY Posts: 517	Ok.... Hypothesis: drinking coffee makes you dehydrated. Now, how can we investigate this hypothesis considering the following facts: 1. We can't afford laboratory services. 2. Nobody wants to bottle up their urine every day, anyway. 3. We're all in different areas. 4. We'll presumably be making our own coffee, so we'll know if it's decaf or regular, as well as what we put in it. 5. We may not all be able to drink the same kind of coffee. 6. We have different coffee makers, and preferneces as far as how strong we make the coffee. 7. Many of the indicators of dehdration or increased urine production are very subjective -- for example, I tend to urinate frequently anyway, so a small increase may not be noticeable. This is why I suggested we can measure our subjective responses to more or less coffee. Volunteers would be good because even though I personally don't notice an increase or decrease in certain symptoms with coffee usage, maybe I would if I tried. I dunno. It's not perfect, so any suggestions?

15th March 2005, 09:04 AM	#27
El Greco Summer worshipper Join Date: Nov 2003 Location: Παρά θιν'αλός Posts: 14,271	Quote: Originally posted by Phaycops Hypothesis: drinking coffee makes you dehydrated. I would rephrase this as "rppa's usual coffee and fluid intake may cause a net water loss". We cannot say that any coffee drinking can cause dehydration. For example I'm pretty sure that even if one drinks 4-5 mugs of coffee each day, one extra glass of water after each mug would be enough to prevent water loss.
	__________________ "Robbing a bank is no crime compared to owning one" - Bertolt Brecht "Let it go and come to bed already, El Greco" - MoeFaux

15th March 2005, 09:08 AM	#28
rppa Muse Join Date: May 2004 Posts: 794	Quote: Originally posted by El Greco I suppose whether rppa's habitual coffee drinking combined with his habitual fluid drinking affects one's hydration state ? That was the title of the thread anyway. Besides, why else would he ask for other participants ? What help would they be of if he only wanted to test his strictly subjective symptoms ? What he said, but about more than my own personal habits. I want to pin down the connection (or lack of one) between coffee and hydration. I'd rather do it with more subjects than just myself. We have a claim in at least one cited source that the water content of coffee balances the diuretic effect. I think that's flat wrong. As a rough guess, I consume somewhere in excess of 36 ounces (1.1 liter) of coffee per day, almost always caffeinated. This may be qualititatively different from drinking 2-3 cups, caffeinated or not. This needs to be tested. Edited to add: On reflection, 36 oz is probably a significant underestimate for those days I wake up feeling dehydrated. I suspect that it's not the caffeine content of coffee, and that decaf would have much the same effect on me. But this needs to be tested as well.
rppa Muse Join Date: May 2004 Posts: 794