Why do I feel unrested when I dream?

I go through phases where, when I sleep, I don't have any dreams (that I remember, at least). I sleep well and I wake up rested. Every few months I go through a week or two when I have nights full of incredibly vivid dreams and I wake up remembering at least five or six of them. Because of all these vivid dreams, I wake up feeling far less rested than I do when I don’t dream at all. Is there a particular reason for this? Does dreaming more at night mean your sleep is less restful?


Is it dangerous to not drink water during sport practice?

I have a question about dehydration. I am an eighteen-year-old female and play on a varsity basketball team. We usually have two-hour practices in which we work very hard. Our coach does not give us water breaks, and usually by the end of practice, we have cottonmouth and are "dying" for water. It is horrible. Is there any way that not having water during that time can be dangerous? Sometimes the team can feel sick or weak by the end of a practice.