Live well with asthma: Peak flow meters – National Consumers League

Even when you feel like you are breathing well, a peak flow meter can alert you to changes in your lung function. You may see a drop in peak flow numbers even before you have asthma symptoms (like coughing or wheezing). This device can help you manage your asthma and may reduce the number and severity of asthma flare-ups.

Keeping a peak flow chart can be very helpful to you, and to your health care provider. You can use it to track your lung function and provide important information on how you are responding to treatment at home so your doctor or nurse can help you with the best treatment plan.

Use and Care of Your Peak Flow Meter

  • Understand how to properly use your peak flow meter.
  • Follow the cleaning instructions. This will help keep the readings accurate.
  • Follow your health care provider’s recommendation on how often you should use your peak flow meter and at what time of day.

How to Graph Your Score

Ask your health care provider to help you determine your personal best peak flow score.

Your personal best peak flow score may change over time. It changes for children as they grow. Discuss this with your care provider at least once a year.

When you know this personal best score, you can graph your peak flow scores into zones:

  • green (best)
  • yellow (caution)
  • red (medical alert)

Using these colors helps you visually track scores that are in your own personalized zones. One easy way to do this is to use highlighters to color in the green, yellow, and red zones on your chart.

Green Zone: This is a score that is 80 percent to 100 percent of the personal best score. This is your goal for optimum management of your asthma.

Yellow Zone: This is a score that is 50 percent to 80 percent of the personal best score. This is your caution zone. Review your daily treatment plan for proper treatment in this zone, which may include a call to your health care provider or increased medication use or dose. If your prescribed treatment is not working, or you find yourself often falling within this zone, you may need to revise your daily treatment plan with your health care provider.

Red Zone: This is a score that is below 50 percent of your personal best score. Consider this your “danger” zone. Contact your health care provider for instruction when you get a reading in this zone.

Work with your health care provider to find your personal best peak flow score and set the color zones. Be sure to get written instructions on what to do when you record readings in each of these zones.

Let’s say your personal best peak flow score, as determined by your health care provider, was 625. Here is how the color zones could look:

Green Zone: Between 80 and 100% of personal best score. Determine 80% of your score to get the “floor” for the green zone. (625 x .80 = 500; green zone ranges from 500 to 625)

Yellow Zone: Between 50 and 80% of personal best score. Determine 50% of your score to get the “floor” for the yellow zone. (625 x .50 = 312; yellow zone from 312 to 500)

Red Zone: Below 50% of Personal Best (chart red zone below 312)

No matter what your peak flow meter number is, get help if you experience asthma symptoms that you and your health care provider have identified in your plan as being serious (such as severe wheezing or chest tightness).