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Go with the Flow

Using a peak flow meter can help you keep your asthma in check. Here’s how.

Asthma image

Monitoring your asthma on a reg­ular basis is an important part of keeping your asthma under control. Keeping track of your symptoms whenever you have them is a good idea. This will help you and your doctor adjust your treatment over time.

Another way to monitor your asthma is with a peak flow meter. This hand-held device shows how well air moves out of your lungs. Measuring your peak flow can help you tell how well your asthma is controlled. It can also alert you to an oncoming asthma attack hours or even days before you feel symptoms. During an attack, it can help tell you how bad the attack is and if your medi­cine is working. The peak flow meter also can help you and your doctor learn what makes your asthma worse, decide if your treatment plan is work­ing well, determine when to add or stop medicine, and decide when to seek emergency care.

It’s a good idea to ask your doctor, pharmacist, or other healthcare profes­sional to show you how to use your peak flow meter. (See sidebar How to Use Your Peak Flow Meter.) The first step is to find your personal best peak flow number; then you can use the peak flow meter to keep an eye on how well your asthma is under control on a daily basis.

Find Your Personal Best Peak Flow Number
Your personal best peak flow number is the highest peak flow number you can achieve over a two-week period when your asthma is under good control; that is, when you feel good and have no symptoms. To find your personal best peak flow number, take your peak flow readings at least twice a day (when you wake up and in late afternoon or early evening) for two to three weeks, 15 to 20 minutes after you take your quick-relief medicine, and any other time your doctor suggests.

Write down the number you get for each peak flow reading. Your doctor will use these numbers to determine your personal best peak flow and create three personalized peak flow zones. These zones are usually set up on your asthma action plan like a traffic light – in green, yellow, and red. Mark the zones on your peak flow meter with colored tape or a marker. What your doctor tells you to do in each zone will help you know what to do when your peak flow number changes.


Use Your Peak Flow Meter to Monitor Your Asthma
Every morning when you wake up, before taking your asthma medicine, take your peak flow. Make this part of your daily routine. Check this number against the peak flow zones on your written asthma action plan. Use the zone that your peak flow is in to help you make treatment decisions.

You should also use your peak flow meter when you’re having asthma symptoms or an attack. First, take your medicine for the attack. Then take your peak flow. This will help you see if the medicine is working for you or if you need more treatment.


Source: National Heart, Lung, and Blood Institute,

This article was originally published in Coping® with Allergies & Asthma magazine, Winter 2013-2014.