How Much Water Should You Drink?

One can find persistent reference in the lay press to the notion that we should all drink a lot of water (8 glasses per day is the most commonly cited figure), but is there science that backs that up? And is there any risk from overhydration? The August issue of the American Journal of Public Health presents a study by investigators from the Harvard School of Public Health suggesting the 54% of US children are dehydrated with highest rates among boys, non-Hispanic Blacks and young children! Any observer of Dartmouth students will notice that nearly everyone carries water around with them and the extent of bottled water consumption is high. However, nearly all the science would indicate that is a myth that one needs to consume large quantities of water per day. Writing in the August 24 issue of The New York Times, pediatrician Aaron Carroll of the Indiana University School of Medicine debunks the idea we are all dehydrated and need to drink extra water beyond what we ingest in many foods and our usual beverages. Furthermore, in a follow-up piece in the Times on August 26 by Gretchen Reynolds highlights the risks of overhydration, particularly among athletes, based in part on a consensus conference statement recently published in the British Journal of Sports Medicine. The consequences of overhydration are not trivial and may, in fact, be severe or even fatal. So, caveat aqua!