Does anybody know the amount of time you have to wait to do peak flow after medication Please? It's just that if I just wait 10 mins e.g. like when did spirometry it doesn't improve that much but after 20-30 mins it does. Reading on the internet Looks supposed to do straightaway. Mine takes a while to improve not sure if this is right? I don't have a proper diagnosis yet and did spirometry and was normal, and didnt improve that much after 10 mins wait after inhaler but was so illl actually doing the spirometry e.g. cough, dizziness, chest the nurse said I had to see the Dr as she couldn't say that I didn't have asthma after this test. I have bunches of pf over last few weeks that say it does tho but they tested me when had Brown inhaler for 6 weeks and had dose of steroid tabs!!