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Asthma Zones

Overview

Asthma zones are part of your asthma action plan. The zones are defined by your symptoms, your peak flow, or both. Knowing what zone you're in can help you know how well your asthma is under control and if you need help.

The three zones are:

Green zone.

Green means good. This zone is where you want to be.

When you're in the green zone, one or more of these things may be true:

  • You don't have any symptoms.
  • You're able to do your usual activities and can sleep without having symptoms.
  • Your peak flow (if you check it) is 80% to 100% of your personal best measurement.
Yellow zone.

Yellow means caution. If you're in this zone, it may mean you're having an asthma attack or that your medicine needs to be increased.

When you're in the yellow zone, one or more of these things may be true:

  • You may not have any symptoms, but your lung function is reduced.
  • When symptoms are present, you may cough, wheeze, or feel short of breath, or your chest may feel tight. Or your asthma may limit your activities or wake you up at night.
  • Your peak flow (if you check it) is 50% to less than 80% of your personal best measurement.
Red zone.

Red means DANGER. If you're in this zone, you may be having a severe asthma attack. Being in the red zone is dangerous. If you're in the red zone, you need to take action right away.

When you're in the red zone, one or more of these things may be true:

  • You may be very short of breath.
  • You can't do your usual activities.
  • You use your chest muscles to breathe. The skin between, above, and under the ribs collapses inward with each breath (retractions).
  • You wheeze. But if your symptoms are very severe, you may not hear any wheezing. Wheezing will stop when the amount of air moving through the bronchial tubes becomes dangerously low. In this case, no wheezing is actually worse than hearing wheezing.
  • Your quick-relief medicine doesn't help.
  • Your peak flow (if you check it) is less than 50% of your personal best measurement.

What to do in each zone

Knowing what asthma zone you're in can help you know what kind and how much medicine to take and when to call for help.

Green zone.
If your symptoms, peak flow, or both are in the green zone, keep taking your asthma medicines as prescribed.
Yellow zone.
If your symptoms, peak flow, or both are in the yellow zone, take your medicine according to your asthma action plan.
If your symptoms don't improve within 20 to 60 minutes or if your peak flow remains less than 70% of your personal best measurement, or if both, then follow the red zone instructions in your asthma action plan. Your lungs are not responding to medicine.
If you keep going into the yellow zone from the green zone, talk with your doctor. Your regular medicine may need to be changed.
Red zone.
If your symptoms, peak flow, or both are in the red zone:
  • Take the actions listed in your asthma action plan, including what kind and how much medicine to take.
  • Talk with a doctor right away or get emergency help right away.
  • Call 911 right away if you've followed your action plan, but:
    • You're having severe trouble breathing.
    • 20 to 30 minutes after taking your medicine, you don't feel better and/or your peak flow is still less than 50% of your personal best measurement.

Credits

Current as of: March 9, 2022

Author: Healthwise Staff
Medical Review:
John Pope MD - Pediatrics
Adam Husney MD - Family Medicine
Lora J. Stewart MD - Allergy and Immunology