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?

Lately, I've come to realize that I have a very powerful tendency to fall asleep in class. It seems that I can't stay awake in any lecture style class where I have to listen to the professor and take down notes — where there is minimal engagement on my part. I've pretty much fallen asleep in all of my lecture classes, during one part or another for the whole semester. I think I'm getting regular sleep — six hours at a minimum. I don't like to drink coffee or anything.

Is sleeping on our left side in any way harmful for the heart (or anything else)? Some people tell me we shouldn't do it and others tell me it's actually better than sleeping on our right side. What's the truth?

Thanks!