I´ve heard a lot of people talking about having an LD in a nap.
my question is, are you always in REM if you take a short nap during the daytime, or do you have to nap for a certain amount of time (90-120 minutes for example), or is it random if you are going to have a REM period.
You might hit REM if you're very REM-deprived already, but otherwise I think it's more likely to be non-REM sleep unless it lasts quite a while. But it could depend entirely on the person.
Personally, the only time I normally feel like napping is when I've not had enough sleep the previous night. But even in those cases it doesn't seem to last more than an hour, and I rarely seem to encounter any actual REM or dreams, unless I had been severely lacking in nightly sleep.