You could use it anytime you wish to sleep. I don't know that using a c-pap at other times would help; it certainly wouldn't hurt, but I don't know if it would make a difference like a bi-pap would.

I am on a asv ... like a c pap and use only at night

I checked with my specialist and he said the daytime pressure could not hurt

I use the c-pap which is compressed pressured air to keep your throat from closing when sleeping.You are given a number in your machine after being tested to have set for you so it fits your breathing problem.I can sleep in my uplift chair without it and no snoring so that is good.

I use mine when I go to bed, whether for the night or I am not feeling well. I also sometimes sleep on a wedge shaped pillow which elevates my upper body.