Reviewed by David Tinkelman, MD

A peak flow zone chart shows you how to check the effectiveness of your breathing.

The following table shows an example of how these zones work. Your doctor can help you create a similar table for your own asthma.

Peak Zone Stoplight GreenGreen: 80-100% of your personal best

  • Your breathing is good.

  • You do not have any early warning signs or asthma symptoms.

    • Take all your medicines every day, as your doctor tells you.

  • Take your inhaler before exercise, as your doctor tells you.


Peak Zone Stoplight YellowYellow: Caution 60-80% of your personal best

  • Runny, stuffy nose.

  • Feel more tired.

  • Chin or throat itches.

  • Sneezing.

  • Restless

  • Red or pale face

  • Coughing

  • Dark circles under your eyes

  • Use "rescue" medicine

  • Recheck peak flows after 20-30 minutes

  • Call your doctor, healthcare professional, or nurse care manager:

    • if your peak flow is not back to the Green Zone

    • if your peak flow drops into the Yellow Zone again in less that 4 hours.


Peak Zone Stoplight RedRed: Danger Below 60% of your personal best

  • Cough, more at night

  • Wheezing

  • Chest feels tight or hurts

  • Breathing faster than normal

  • Get out of breath easily

  • Use your quick-relief medicine by inhaler or nebulizer right away!

  • Call your doctor or 911 NOW

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