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Asthma Diary

Topic Overview

An asthma diary helps you keep track of how well you are managing your asthma.

If you have symptoms or an asthma attack, record the trigger (if possible), the symptoms, and what kind of medicine you used for relief and how well it worked. Also note if you had to contact your doctor or seek emergency care. This can help you know your triggers and help your doctor monitor your treatment.

If your doctor recommends it, measure your peak expiratory flow (PEF) often, every morning and evening if possible, and record it in your diary. It may be helpful to record your PEF using the same green, yellow, and red zone system used in your asthma action plan.

Here is an example of how to use an asthma diary if you are keeping track of peak flow.

Week of October 12

My personal best peak flow is 400 litres per minute. My:

  • Green zone is 340 to 400 litres per minute (85% to 100% of my personal best). To figure 85% of your personal best peak flow, multiply your best flow (in this example, 400) by 0.85 (in this example, you get 340).
  • Yellow zone is 240 to 339 litres per minute (60% to less than 84% of my personal best). To figure 60% of your personal best peak flow, multiply your best flow (in this example, 400) by 0.60 (in this example, you get 240).
  • Red zone is less than 240 litres per minute (less than 60% of my best).

My current long-term (controller) medicine is fluticasone.

Example of an asthma diary





Quick-relief medicine and response

Red zone visit to doctor/hospital?





3:50 a.m.

3:00 p.m.


Improved PEF







Eliminated wheezing



Adaptation Date: 8/18/2021

Adapted By: Alberta Health Services

Adaptation Reviewed By: Alberta Health Services

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