about the pft tests??

[jimgreg]

on these test do you feel as if ur getting light headed??  i breth in and out for the doc to lisen to my chest  and get light headed..is this the o2    and co2????    explain the tests..i feel like i can blow good and take in air full...but i took this  test for the state for my disability..i just rember a metal mouthpiece..and some brething,..but most of it felt lie i was brething against something  was in the way.......so is this nor free brething..or do they test by the  way you breath again pressure or both???  anything  will help thabk you

[jimgreg]

that's  why you take the same  test  over 3-4 times 4 tests...

[allmymarbles]

And I have a related question of my own. Whenever I take the usual breathing test I start to cough. How can they get an accurate measurement if I cough?