Sit up! Lie down!
Como se dice "Sit up" if someone is lying down y "Lie down" if you want them to lie down'
18 Answers
Sit up! = parate!
Lie down! = acuestate!
That simple, Asi de facil.
Maybe not that simple. I have heard ¡Párate! used for "Stand up!," but never for "Sit up!" Are you sure that you understand the English here? If you do, then are you sure that ¡Párate! can be used to tell a person lying in bed to sit up? That would be news to me.
I would have thought parate was second person imperativo for stop´
Ken-
Sit up! = párate!
Lie down! = acuéstate!
That simple, Así de fácil.
Just to add that ¡Párate! in Spain means, Stop!
Acuéstate: Go to bed, go to sleep
Gus is right, nothing is easy in language. 
Sit up! = parate!
Lie down! = acuestate!
That simple, Asi de facil.
levantate could be use for sit up
echate to lie down
acuestate could be use to lie down
I think that parate means to stand up
when it comes to language, nothing is simple.
Sit up! = parate!
Lie down! = acuestate!
That simple, Asi de facil.
Maybe not that simple. I have heard ¡Párate! used for "Stand up!," but never for "Sit up!" Are you sure that you understand the English here? If you do, then are you sure that ¡Párate! can be used to tell a person lying in bed to sit up? That would be news to me.
Sit up! = parate!
Lie down! = acuestate!
That simple, Asi de facil.
It could refer to either, but generally, more to the first one.
The context would be in a doctor's office telling someone to "sit up" or please "lie down on the table." It's just for curiosity's sake
A doctor in Spain would probably say "Levántese / Incorpórese" (this would mean to regain a vertical position, either sitting or standing), "Siéntese" (for a sitting position in general), and "Acuéstese". For "sit up", you'll have to go for something like "Siéntese derecho/a" or "Póngase derecho/a".
Why can't we delete these?
Whoa! changing from Normal to Guided is interesting.
Is that why they call it a permalink'
A doctor in Spain would probably say "Levántese / Incorpórese" (this would mean to regain a horizontal position, either sitting or standing)
I'm pretty sure you made a typo here, and meant to write "vertical position," right? If not, then I am confused.
For "sit up", you'll have to go for something like "Siéntese derecho/a" or "Póngase derecho/a".
Just to make sure we understand each other, "sit up" can mean two things: sit up straight (don't slump over; sit with good posture (a straight back)), or raise yourself from an inclined (horizontal) position to a sitting position. The original question here refers to the second of these, but I think your translations refer to the first. Am I right or wrong'
As a command for a dog, lie down! = ¡échate! / ¡échese!
'? Am I misunderstanding again? When someone tells you "Levántese" is he not telling you to go from a horizontal (lying down) to a vertical position (standing/sitting up).
Nope that's what I wanted to know 
The context would be in a doctor's office telling someone to "sit up" or please "lie down on the table." It's just for curiosity's sake
... but why was the person lying down to begin with if not to sleep.
Well, if these commands were to a pet rather than "someone" I don't think sleep would be involved.
The next time that your doctor tell you to lie down on his examining table or your psychiatrist (we all have one of those, don't we') tells you to lie down on his couch...go ahead and nap for a few hours, then see what your bill is, and tell me if you feel rested and invigorated. 
Would either of the following suffice.
siéntate derecho; siéntete firme or quedate despierto hasta tarde; I know the last one is a bit tenuous but why was the person lying down to begin with if not to sleep.
I think the first one means "Sit up straight," as in "Sit with good posture." The second one sounds like "sit firmly," maybe something you would say to a motorcycle passenger, but I'm not sure. The third one means "Stay awake until late," so it is not the right translation here.
As to why someone would say this, I can easily imagine someone lying on a sofa, watching TV, when another person enters the room and says "Sit up, I need to talk to you." "Levántate, que necesito hablar contigo."
¡Siéntate!
I don't think that's right. Remember that the question is "Como se dice 'Sit up? if someone is lying down'" Sentarse means to go from a standing position to a seated position, but not, as far as I know, from a reclined position to a seated position. I think the correct translation would be "¡Levántate!" I realize that that is ambiguous, as it could mean either "Get up!" or "Sit up!," but I think that is how it is said. Corrections welcome.
James has a valid point, Damn! as always. Would either of the following suffice.
siéntate derecho; siéntete firme or quedate despierto hasta tarde; I know the last one is a bit tenuous but why was the person lying down to begin with if not to sleep.
