h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

What if I sleep standing up ?

Let the imaginary line from my head through my spine be the axis of my body.
Let us assume that the bed itself plays no actual part in proceedings since we can sleep in, on or under anything we like (including other humans - I'll come to that in a moment).

Well, if it is just the left/right thing then I suggest this experiment: Sleep face to face on top of another human. Then, on waking, both get out of the same side of bed. If one is grumpy and the other is not then we know that the 'wrong' side is relative only to the human. If both are grumpy then it is bed-specific, in which case you can both continue getting out of the same side (the other one).

Back to the sleepign standing up thing...
Surely, there must be some first movement off my axis when I wake up. This would equivalent to some angle relative to my initial starting direction. That means that the range of possibilities for 'wrong' are now infinite (I can step forward, backward, sideways, jump etc).

Now, if it isn't a right/left thing then it is a smooth continuum of 'wrongness' from, say 0-1 (wrong being completely BAD). If you sleep standing up, then your degree of wrongness is likely to be pretty small (assuming that the angle of ultimate wrongness changes daily). Over a lifetime of sleeping standing up you would accumulate only very few actual totally grumpy days.
And probably only a few actual hours of sleep.
Unless you were an astronaut.