How much does lying down affect peak flow normally?

[GreatGateway]

Sorry for so many questions, just covering all bases while I keep good records for my GP. I noticed that usually my peak flow drops when lying down. Is that normal even in non-asthmatics? If it is how much of a drop is ok?

[Minushabens]

I've never tested that but it's logical I guess. I was always told to either stand or sit up straight to do it. If you are getting symptoms when lying down then that's a different issue, but I wouldn't worry otherwise about PF readings.

[Hidden]

Hi it is best to take your peakflow standing up or sitting down if you are too poorly to stand up. Same goes with inhaling. I sleep propped up at night, I breathe better.