[Richard Hoevelmann]

Richard Hoevelmann  asked the Naked Scientists:
   
There is a question that has been bugging me for years and as I have recently become a regular listener of the podcast I thought you might be able to shed some light on the matter:

I have often noticed that when I wake up in the mornings after being woken up mid-dream by my alarm clock that I regularly have a distinct pillow imprint in my face which usually takes a good half hour to disappear.

However - if I wake up not remembering what I have dreamt, alarm clock or no, I never seem to have said lines running all over one of my cheeks, even though I make my way equally hastily to the bathroom mirror.

My guess is that it has something to do with the deepness of sleep and is due to having not moved my head for a while but I would be intrigued to know if there is perhaps a more complex explanation? Is it possible that my blood pressure changes depending on what I am dreaming and thus enables the creases in the pillow to imprint themselves on my skin more easily?

Please help
Richard

What do you think?

[RD]

When you are dreaming you are paralysed ...

Rapid eye movement sleep, or REM sleep, accounts for 20–25% of total sleep time in normal human adults. The criteria for REM sleep include rapid eye movements as well as a rapid low-voltage EEG. Most memorable dreaming occurs in this stage. At least in mammals, a descending muscular atonia is seen. Such paralysis may be necessary to protect organisms from self-damage through physically acting out scenes from the often-vivid dreams that occur during this stage.

http://en.wikipedia.org/wiki/Sleep