How does thinking of dreams cause sleepiness?

September 2, 2006 9:57 AM

When I wake up, I lie in bed and think. Gradually, I get more awake until I'm ready to get up. But, if I think about the dreams I just had, I get overpoweringly sleepy again. Why is it that thinking about anything else helps me to continue gently waking up, but thinking about dreams puts me immediately and irresistibly back to sleep?

Of course, if I start thinking about stressful things like work or things on my to-do list, it makes sense that I get more awake, but I've been experimenting with this, and I get more awake even if I think completely non-stressful thoughts, as long as they're not my dreams. Also, if I think about dreams later in the day, I don't get noticeably sleepy.

If my experience isn't just an oddity, I'm interested in what biological mechanisms or other principles could explain how thinking about dreams causes sleepiness.

posted by daisyace to science & nature (11 comments total)

You could just be tricking yourself into getting more sleepy when you think about your dreams because that's a cool effect. Auto suggestion.
posted by shivohum at 10:43 AM on September 2, 2006

It probably has something to do with the reticular activating system, the part of your primarily responsible for the somatic elements of sleeping and dreaming (drowsiness, REM paralysis).
posted by owhydididoit at 10:44 AM on September 2, 2006

your brain primarily

apparently, the very question evokes something in me as well :)
posted by owhydididoit at 10:45 AM on September 2, 2006

Cute tags. I think this is a highly individual question. It does make sense that thinking about your waking life ("stressful things like work or things on my to-do list") would bring you into full consciousness.

On the flip side, the concept of dreams seems to be intimately linked to sleep for you. For example, if I have recently broken up with my girlfriend, thinking about the first song we listened to (or hearing it) might bring me back to the "sad" state I associate with her. In this case, thinking about dreams seems to be connected to sleep. Our emotions, dreams, and thoughts are a complex web - thinking about dreams = sleep, which produces an affective state.

See here. Also reading about psychology and the way our emotions can be manipulated and created by our thoughts are also subjects to dig deeper into for an extended answer to your question.
posted by ifranzen at 10:47 AM on September 2, 2006

It may just be simple classical conditioning - you associate dreams with sleep, therefore thinking about dreams makes you sleepy.
posted by biscotti at 11:11 AM on September 2, 2006

It may just be simple classical conditioning

Seconded. See here.
posted by ifranzen at 11:15 AM on September 2, 2006

Conditioning is a good, simple possibility. The next morning that I wake up slowly, I'll test the idea by thinking about other things that I associate with sleep (e.g., my bed and stuff on it, and my getting-ready-for-bed routine). My suspicion is that it won't make me sleepy. I know that biases the experiment, unfortunately. But, say I could give it an unbiased try, and it didn't make me sleepy... Do any alternate explanations come to mind?
posted by daisyace at 11:41 AM on September 2, 2006

Daisyace, I'm skeptical of the conditioning explanation.

My Merck Manual (1999, p.1409) shows a diagram of typical adult sleep which has a brief period of awakening 4 times during the night, in each case preceded by an episode of REM sleep, and followed by an immediate return to one of the other stages of sleep. The final awakening pictured on this diagram takes place out of stage 1 sleep, not REM sleep.

I take your report of your experience as evidence that dreams have some kind of design feature to put you back to sleep when you wake up out of one, and that if you don't take immediate action to maintain wakefulness, you will by default end up going right back to sleep.
posted by jamjam at 2:45 PM on September 2, 2006

This is just a guess but my experience is that dreaming is often an enjoyable/engrossing/fantastical mental state. So if I'm dreaming of flying or visiting someone who is deceased or whatever, when I wake up I often want to "return" to this dream state and if my circumstances allow (a day off, weekend, holidays), I often do to try to "recapture" that feeling or that reality - sometimes successfully, sometimes not.
posted by Jaybo at 2:44 AM on September 3, 2006

When I wrote this, I suspected that it was something that happened to lots of people. If it did, there'd probably be a biological reason, and I was curious what that could be. Jamjam went along with my suspicion, and proposed a really intriguing possibility. But, having not heard anyone say that it happens to them, too, I guess it's unlikely that anything that intriguing actually applies. The impartial side of me has to admit that either shivohum's explanation or some other confusion of cause and effect is likely, even though it really doesn't feel like that's what's happening! Anyway, thanks for the responses.
posted by daisyace at 6:03 AM on September 4, 2006

It happens to me too: if I can remember what I was dreaming and concentrate on it, I can usually get back to sleep. No idea why.
posted by mmoncur at 2:15 AM on September 6, 2006