Uhhh.....yeah.
The simple answer is, drink all you want, we'll make more.
> > > I have always wondered if you drink so much water does it affect your > > >kidneys adversely by overworking them ? > > > > > > > > > James here..... > > > > It would be interesting to see what Dr John has to say, it is so nice to > > have him on the list. I have always understood by making urine more dilute > > it is better for you. > > Normal kidneys filter a straight percentage of the amount of blood that > passes through it. This is an oversimplification of a process that involves > the amount of dissolved salts, serum proteins and blood pressure, but for > purposes of this list, suffice it to say that a fixed fraction of the amount > of blood that passes through the kidney is excreted as urine. Thus, the > more blood volume that passes through, the more urine made. The blood > volume is increased by consumption of more fluid, but the intestines can > absorb fluid at a fixed rate in the hydrated state (again, an > oversimplification). If one consumes more fluid than one can absorb, the > stool is more hydrated; if there is enough fiber, it absorbs it; if not, the > stool becomes loose. OTOH, intravenous fluid has no limit in how much can > be put into circulation. > > The reason there are limits to absorption is not because of the kidneys but > because the heart has a limit to how much it can pump through the kidneys. > If the limit of cardiac output is reached, fluid accumulates in higher > volumes in the blood and the fluid pressure forces it into the tissues, > resulting in edema. Again, orally, this is almost impossible to do in a > healthy person. > > If fluid intake is maximized, urine is very dilute when it is made since > much more water is put into the urine. If fluid intake is maximized, the > blood flow to the mucus membranes is adequate so the mucus glands can > produce mucus that is thinner. As the volume of blood drops, the > circulation is reduced to noncritical organs such as the airways in favor of > the brain and other critical organs. Consequently the mucus gets more > viscous. > > Other benefits to adequate hydration are reduced incidence of bladder > infections for women by reducing the chance of bacterial growth to the point > of invasion of the bladder wall, improved perspiration for temperature > regulation, improved skin hydration, reduced risks for stone formation in > the kidneys and salivary glands, etc. > > I hope that explains it. > > John > > John J. Messmer, M.D. > Assistant Professor, Family & Community Medicine > Penn State College of Medicine >
John M. Schweinfurth, MD Laryngology and Professional Voice Care Assistant Professor Penn State University Medical Center Hershey, PA (717) 531-6822
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