I have heard that caffeine (a small cup of strong coffee), is good to give you a bit of en edge if say you are off for an hours run. Anyone know how this works, or how true it is?      

I've heard that we should drink about 2.5 litres of water every day as a way of cleansing our bodies and also providing the fluids we need. I take it that this doesn't include tea, coffee or other drinks laden with caffeine and other additives.