How many glasses of water should you have a day?

Actually, eight is too many.

You lose every second of water through exercise etc.

In 1946 a British Medical Journal report stated that adults should drink 2.5 litres of water daily, but they said that "most of this quantity is contained in prepared foods." After being compiled, this sentence seems to have fallen by the wayside.

Drinking lots of glasses of water will only make you urinate more.