This topic has been mentioned a couple of times in the past without there being any conclusion as to what is happening, but I am wondering if I have the answer..

Ok, so what has happened a few times to me is that I dream I am so sleepy in my dream that my eyes cannot stay open, no matter how hard I keep trying. Yet how can this be as I am asleep and dreaming?

Firstly, in my case I have sleep apnea, which means that I stop breathing in my sleep several times an hour. The brain wakes the sufferer up to start breathing, but one is not aware of this happening. However they say that you don't experience as much deep sleep (ie non REM sleep) in the night (explaining why I so often have to have extra sleep during the day).

So what I think happens is that the body is trying to get some deep sleep but the breathing issues prevents it, so during REM sleep you feel tired because you actually are and dont want all the brain activity of REM sleep.

I am very curious of other people's experiences and whether or not they have sleep apnea or any other sleep disturbances that they know of. I personally dont think these dreams are just the result of daytime tiredness.