The asthma traffic light system is a system of color-coded zones that classify symptoms into three categories: green, yellow, and red. The system can make it easier to identify the severity of asthma.
Asthma is a
An asthma action plan is a document that outlines three zones of asthma and how to manage them. One is example is this plan from 2007.
In this article, we will explore what the traffic light system for asthma is, the different zones, alternative asthma action plans, and whether asthma action plans are effective.

Asthma requires self-management as it can intensify quickly and unpredictably. Treatment can rapidly provide relief from symptoms.
An
These zones make up the traffic light system and are typically categorized based on the results of peak flow recordings.
The asthma action plan means some people may be able to manage asthma exacerbations on their own if the condition starts to worsen, which may help
Learn about unmanaged asthma and the asthma control test.
The green zone of an asthma action plan describes the best living condition for people with asthma. This means there are no symptoms that disturb daily life and people
- have no symptoms
- be able to perform daily activities
- have no difficulty sleeping due to coughing, wheezing, or breathing difficulties
- have peak flow recordings of at least 80% of their personal best measurement
People in the green zone typically have mild asthma but are still at risk of severe exacerbations.
An asthma action plan for people in the green zone
Learn about the stages of asthma, from mild to severe.
Within the yellow zone, people may experience sudden difficulty
In the yellow zone, people may experience the following:
- no symptoms but a decrease in lung function
- symptoms that include coughing, wheezing, shortness of breath, or chest tightness
- limits to typical activities
- sleep disturbance from symptoms
- peak flow recordings being 50–80% of their personal best measurement
People in the yellow zone will typically take medications in line with recommendations on the asthma action plan. There are instructions to follow if the peak flow score does not increase or symptoms do not ease within a certain timeframe.
If a person’s asthma enters the yellow zone frequently, they may need to speak with a doctor about changing their medication.
The red zone is for asthma with the
The red zone of asthma may involve the following:
- shortness of breath
- difficulty completing daily activities
- using the chest muscles to breathe
- wheezing
- fast-relief medication not helping
- peak flow tests showing less than 50% of their personal best measurement
If in the red zone, people should follow their asthma action plan and speak with a doctor as soon as possible. Call the emergency services if:
- a person is having severe difficulty breathing
- peak flow scores do not increase above 50% of their personal best measurement after 20–30 minutes
- symptoms do not ease with medication after 20–30 minutes
Asthma action plans are effective and extremely important, as they enable a person to recognize their symptoms and respond appropriately to worsening symptoms. The plan can help
Every person with asthma should have an asthma action plan in writing.
Asthma can flare up to different degrees of severity. When this happens, an asthma action plan helps a person determine the severity and how they should respond.
An asthma action plan divides signs and symptoms into three color-coded zones, with a red zone for the most severe situation and green for the lowest intensity. This is what people commonly refer to as the asthma traffic light system.