- #1
thunderfvck
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WHat reactions consume so much water in the digestion of ethanol?
Why does exercise decrease the diuretic effect of caffeine?
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Discussion Overview
The discussion centers around the relationship between exercise and the diuretic effects of caffeine, exploring how physical activity may influence the body's response to caffeine and its impact on urine production. Participants examine the physiological mechanisms involved, including the roles of vasopressin and glomerular filtration rate, while also referencing the effects of alcohol as a diuretic.
Discussion Character
- Exploratory
- Technical explanation
- Conceptual clarification
- Debate/contested
Main Points Raised
- Some participants note that alcohol acts as a diuretic by inhibiting vasopressin release, leading to increased urine output.
- There is a question about whether caffeine is also a diuretic, with some asserting that it stimulates kidney function and increases urine production.
- One participant mentions that caffeine's diuretic effect is more pronounced at rest compared to during exercise.
- Another participant references studies suggesting that caffeine does not lead to increased dehydration in athletes who consume it before exercise, indicating a potential difference in effects based on activity level.
- Some participants speculate that exercise may override caffeine's diuretic effects, possibly due to changes in metabolism or blood flow distribution during physical activity.
- There is a discussion about how chronic caffeine use may lead to reduced sensitivity to its diuretic effects.
- One participant proposes a physiological explanation involving changes in blood flow to the kidneys during exercise and the release of antidiuretic hormone, which may counteract caffeine's effects.
Areas of Agreement / Disagreement
Participants express varying views on the diuretic effects of caffeine, with some suggesting it is not a diuretic during exercise while others maintain that it has diuretic properties. The discussion remains unresolved regarding the exact mechanisms and effects of caffeine in relation to exercise.
Contextual Notes
Participants mention the need for further studies to confirm their assumptions about the physiological mechanisms at play, indicating that current understanding may be incomplete or based on extrapolation rather than direct evidence.
- #2
Chemicalsuperfreak
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Alcohol is a diuretic. It makes you piss all your water away.
- #3
adrenaline
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alcohol causes diuresis presumably resulting from inhibition of vasopressin (also called antidiuretic hormone) release from the posterior pituitary gland
- #4
Monique
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Is caffeine a diuretic too?
- #5
adrenaline
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Yes..due to direct stimulation of the secreting apparatus in the kidney, as well as by generally raising the arterial tension in the renal tubules. For some reason this action is more apparent at rest than during exercise.
- #6
Monique
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It's seems that the scientific community says it isn't, so maybe something is wrong with me, 'cause my experience is that coffee and coke both make me have to use the bathroom
- #7
Monique
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It IS? That makes me feel better but it doesn't interact with vasopressin?
- #8
adrenaline
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From the medical community standpoint, caffeine is no more a diuretic than water during normal exercise status (studies by a exercise physiology guru Armstrong) demonstrated no more dehydration in those athletes who preceded their workouts with caffeine. However, most people have taken his data and extrapolated to caffeine is not a diuretic. At rest, or in couch potatoes it is. Also, with chronic usage you become less sensitive to the diuretic effects.
- #9
Monique
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lol, so that is scientific proof I'm a couch potatoe anyone else? 
but no, apparently the exercise overrides the diuretic action of caffeine, maybe it gets metabolized faster?
but no, apparently the exercise overrides the diuretic action of caffeine, maybe it gets metabolized faster?- #10
adrenaline
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Not sure about the mechanism of action there. Will need to look into it.
- #11
adrenaline
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Originally posted by Monique
lol, so that is scientific proof I'm a couch potatoe anyone else?
I could not find any specifics but I will extrapolate based on basic exercise physiology. Remeber, caffeine in sedentary state increases urine output by increaseing the GFR or glomerular filtration rate by increasing the afferent blood flow to the renal tubules and also somehow works on the distal tubules in terms of sodium reuptake regulatory mechanism. At rest, 15-20% of blood goes to skeletal muscle; during exercise, this amount increases to 80-85%. Thus blood flow to visceral tissues and inactive skeletal muscle reduces and kidneys reduce. We also start releasing antidiuretic hormone which probably overrides the caffein's effect on the distal tubule in terms of sodium reuptake and the general shunting of blood decreases the glomerular filtration rate. I have yet to find actual studies to confirm this but that is my basic assumption.