"Drink at least eight glasses of water a day." Really? Is there scientific evidence for "8 × 8"? [View All]

[RC]

WE SEE THE EXHORTATION EVERYWHERE: "drink at least eight glasses of water a day" (17). The advice comes not only (as in the above quote) from a respected health columnist of The New York Times, but also from numerous writers in the popular press (3, 6, 10, 26, 54). Some, perhaps many, physicians counsel their patients in a similar vein, both orally and in writing. So prevalent is the recommendation that it is now commonly expressed simply as "8 × 8" (signifying that each of the 8 glasses in question must have a volume of 8 oz).

As we look around us in our daily activities, we can observe how slavishly the exhortation is being followed. Everywhere, people are carrying bottles of water and taking frequent sips from them. Prior to September 11, when there was little restriction on how much baggage passengers could carry onboard airplanes, it was common to see young professionals loaded down with luggage---garment bags, carry-ons, computers, pocketbooks---while simultaneously juggling a cell phone in one hand and a bottle of water in the other. The practice continues today, although the passengers may perforce be less encumbered with luggage. It is perfectly acceptable to sip water anywhere, as during lectures, seminars, and conferences. A colleague has told me he estimates that something like 75% of his students carry bottles of water and sip from them as they attend lectures; indeed, a pamphlet distributed at the University of California Los Angeles counsels its students to "carry a water bottle with you. Drink often while sitting in class..." (3). I have seen a professional concert pianist walk onstage carrying a glass of water, and a well-known columnist bring his own bottle of water to his interview on a nationally televised talk show. For some, the bottle has even become a security blanket: recently, as I listened to a postdoctoral fellow presenting a seminar, I observed that whenever his flow of words stopped momentarily, while he contemplated the next sentence, he would, seemingly unconsciously, pick up a bottle of water from the table, unscrew its top, and replace it, without ever taking a sip.

This review deals with the origin of our new national habit of 8 × 8. How did it start? Is there any scientific evidence that supports the recommendation? Does the habit promote good health? Might it be harmful?

>The Rest @<
http://ajpregu.physiology.org/cgi/content/full/283/5/R993

It is a good read. Gets your mind of Hillary as president for a while.