Peak flow

[Rhino03z]

I've been given a peak flow and a chart to keep a tally for 2 weeks the numbers on peak flow is comming up as 300-350 asthma charity said my age is should be about 580 im 27 and weigh 9stone does anyone no if 350 is good or bad

[Js706]

Peak flow is something that is really individual. The charts they use for a predicted value are based on an average across the population for a certain age, height and sex. Normally they’re used as a rough start point until you know your personal best.

The main thing with peak flows is to get to know your personal best value - as most asthma management plans will be based around this. If you’re undergoing the process of being diagnosed with asthma then they often get you to monitor peak flow for a couple of weeks to see if it varies from day to day/throughout the day as this can be a sign of asthma or to see if it improves with treatment (if you’ve been given an inhaler to try).

If you’ve been given an inhaler to try you may well find that it starts to increase as the 2 weeks goes on and the inhaler starts to build up in your system and help. It may also stay at the current level - this can either mean that that is your personal best at the moment or your asthma needs some more treatment still to help improve things.

As I said at the start though it can really vary from person to person as loads of different things can affect it. Not just age and height, but also things like technique, fitness, playing sports, playing instruments, doing singing etc! And it isn’t necessarily anything to do with how bad your asthma is either. I have severe asthma, with a best peak flow of 500, whereas my mum has moderate asthma with a best peak flow of 300 and my grandma has very mild asthma, but her best peak flow is only about 250!

So try not to get too hung up on exact figures for now, until you have more of an idea about what is normal for you

Hope that helps explain things a bit - let me know if you have any other questions about it!

[EmmaF91 Community Ambassador]

Completely agree with Js706. There are lots of factors that affect best PF, so just record what you get and see what they say.

If it helps reassure you my friend and I have exactly the same predicted score (440). I have severe asthma, she has no respiratory issues at all. My best is 630, her best is 300.

It’s not about your best score, so much as how it varies through the day, if you have symptoms and if you respond to asthma medication (my first ever best score was about 500ish... within a year of sorting out my medication regime I was hitting 630). If there is something going on you may find your best improves but if it doesn’t it doesn’t matter. With asthma the concern is about how much it fluctuates compared to your best... for example if I hit 200 I’m at 31% and am usually heading to resus, however for others on here 200 is 80% or higher than their best, and nothing to worry too much about.

As I child I was a very high level sports person in multiple sports hence why my best is so high 😅.

Hope this helps and as I said Js706 has it spot on!

[Dietrech]

My best is 300 but mostly 250, or less when my chest is bad! It’s. A guide to help your doctor and you judge if things are improving or getting worse! I don’t worry about mine, I judge more by my oxygen level!

[hilary39]

I agree with everythine everyone said above! We have a wise community here

One additional thought from my own experience--I often find that my peak flow doesn't vary much even when I'm in a really bad exacerbation or attack. My doctor explained that it's because severe asthma often manifests in the small airways and the peak flow measures the big airways only. Just an FYI.

[Junglechicken in reply to hilary39]

I’ve heard this too hilary39. Some of us can be very ill with a peak flow close to personal best. I had a chat with an AUK nurse who said the same thing. I’m symptomatic (cough, chest pressure, a quiet wheeze at night) frequently at the moment with hay fever season. My PF is at 92% and jumps close to my PB with salbutamol. My new GP was concerned that I’m using my blue (at least once a day) more often than she would like. I need to go in for a review ASAP.

[Tengudreams]

Yes I question how important peak flow is. I can easily score 700-800 when Im not feeling very well. Wish it was a better marker of how my day would be haha