How do I know if I’m dehydrated?
To measure hydration status, check your urine concentration (indicated by color) and volume (amount of urine you make). Your urine should be pale yellow or straw colored. If urine is dark yellow, and there’s not much of it, chances are you’re dehydrated. (Remember that certain vitamin supplements and foods may also change the color of your urine.) A reduction in body weight of at least 2-3 percent of body mass at the end of vigorous exercise represents a loss of body water that needs to be replaced.