For all runners dehydration is a very serious concern. There are all kinds of myths that have popped up about how much water should be taken in during a bout of exercise or during running.
One of the most underused and least understood marker of hydration levels is the color of urine. Boy Scouts of America has posted a Urine Color Chart which allows you to gauge your hydration level depending on the color of your urine.
Sources: Boy Scouts of America via Flowing Data.
