Let's drink to that!
Humans are blessed with thirst - a wonderful in-built system telling us when we need to drink.
There are times when thirst doesn't function well, but for most people, thirst is an excellent guide to our fluid needs. So how accurate are the common media messages relating to fluid needs?
Eight glasses of water
Some years ago, Professor Heinz Valtin, the author of several textbooks on kidney function, wrote an excellent review discussing the rationale (or lack thereof) for eight glasses of water a day.1
Valtin traced the claim to recommendations made in 1945 by