Why You Need to Drink a Lot of Water When Running

I started running since 2005 with 800m a day. Now sometimes I may run even 10km a day. My secret is that I always am doing it for pleasure and health. I made a research about drinking water during the running. At the beginning of my running I had a lack of information about that. I started to read advices and tips which made me think that you absolutely can not drink while running but that's not true. During these years nothing has changed, tips are giving all who want to keep attention on them, even if they don't know about what they are talking, being usually wrong. From my experience I can tell about water during the running the following...