Peak Expiratory Flow Rate: How We Measure and Why?

Nov 9, 2020 | PEF

* Peak Expiratory Flow is measured by you, several times a week using a small pocket-sized flowmeter

* You record the number measured by this devise.

* This number shows how well you are able to exhale and tells me if we have your lung inflammation under control

* When this number starts edging down over a few days, we know its time to take action before you start to feel symptoms of chest tightness, shortness of breath or actual wheezing.

* I use Peak Expiratory Flow measurements and ACT scores in your Asthma Action Plan to help guide you in responding to changes in your lungs.


In order for you to self-manage your asthma, you need a way to detect early drops in your lung function.

Peak Expiratory Flow (PEF) is that way.

It is measured using a device held up to your lips while you forcefully exhale.

This device measures how much air is exhaled and registers this as a number for you to read from the device.

When your lungs are in good control, the number reading for your PEF will be very similar to that of a person without asthma.

When your inflammation gets out of control, the swelling in your breathing tubes blocks air from being exhaled.  This results in lower numbers on your PEF device.

When this device is used daily, you will be able to detect a downward trend that is a sign of worsening inflammation days before your breathing becomes so labored that an ER trip is needed.

Peak Expiratory Flow:  Let’s make it a daily measurement!

If you need a Peak Flow Meter and your pharmacy or doctor can’t help, you can order from Amazon.  I have tested most peak flow meters available on Amazon and recommend the following:

The Nascool or Sonmol has a digital display, is also portable, compact and durable and less expensive than many other digital designs.

PEF: Nascool Peak Flow Meter

My previous non-digital flow meter (Omron) no longer appears on Amazon!

I may earn commissions for purchases made through these links.