Asthma UK community forum

Potential Asthma Diagnosis - Peak Flow Readings?

I went to GP as I was having trouble when running, about 10mins into it my chest hurts, i get a phlegmy cough and its like trying to breath through a straw. I've been given a peak flow meter to record am/pm and before and after exercise. Usually on resting its 530 (which apparently is high for my sex/age/height) and after exercise has been as low as 390.

Since doing the monitoring I've also found it can drop to 450 even when I'm not exercising (or doing anything in fact) with this I get a tight chest, get agitated and cross with the kids and feel quite tired, this can go on for a few hours (In fact i'd been to GP previously with tiredness, they checked bloods for anaemia and hypothyroidism but they were fine) i'd never really thought about it before but the symptoms tie in with the low peak flow reading.

Trouble is I don't know if these changes in peak flow are significant? I'm not seeing my GP for another 3 weeks when I have a spirometry test booked. Also what if they do the spirometry test on a good day? It won't pick up the changes on a bad day will it?

This is all new to me and I'd appreciate some advice from those who have more experience. Sorry my post rambles on!!

2 Replies


Peak flows tell you your best and worst so give u an idea how your asthma is doing.

I have had high pf and still bad and also tests that have been ok with the readings but still bad with my asthma.

keep a record over few weeks and see how you go.this will give you an idea

how your asthma is doing but go by how you are feeling also as my pf doesnt always drop

for a few day or so after I start having breathing probs .love Glynis xxxx


as you have kind fo said yourslef your peak flow normal are dependant on several values

you might be interested to know what your predicted paek flow is which will give you an idea as to how your current peak flow reading compares.

have a look at OR

the first one gives you a rough predicted value upon entering your gender height and age

the second is a graph you can work it out from

if you are keeping a record of your peak flows you will be able to show your doctor this and (S)he will see how it can change daily ect. when you see your gp discuss what is seen as your normal value as everyone is different and what kind of drop you should consider as significant specifically for you.

just an example which might make it clearer using figure's :

my normal value peak flow acording to average graphs ect (like the ones in the links above) is in the region of 440- 460

however i have never ever in my life reached this

on this basis what is considered as my normal by me and my gp is in the region of 350 to 370 although my best is usually 350, and i know if it dips below 300 something is probably up!

but not evryones peak flow is a sign something is wrong, and this is very important becuase we are all different. for example in previous attacks my peak flow has been known to drop as low as 190 and other attacks has remained at around 350,

so basically what im trying to say is find out what your normal value should be continue monitoring your pf but remmber pf doesnt tell everything! if at any time you feel concerned or your condition changes contact your gp asap , if it would put your mind at rest try and see if you can get an appointment with your gp before the spirometry,


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