Dehydration can affect mood, concentration and overall health. But new research suggests that chugging huge amounts of water may not be the best way to hydrate. It's better to drink water while eating so that the water doesn't just pass through immediately. David Nieman, Health professor, via Time Clear urine is a sign of over hydration, which could be dangerous. The National Academy of Medicine recommends that women and men drink 91 and 125 ounces of water a day.