Topic Overview

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

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 liters per second. My:

  • Green zone is 320 to 400 liters per second (80%
    to 100% of my personal best). To figure 80% of your personal best peak flow,
    multiply your best flow (in this example, 400) by 0.80 (in this example, you
    get 320).
  • Yellow zone is 200 to 319 liters per second (50% to less
    than 80% of my personal best). To figure 50% of your personal best peak flow,
    multiply your best flow (in this example, 400) by 0.50 (in this example, you
    get 200).
  • Red zone is less than 200 liters per second (less than
    50% of my best).

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

Example of an asthma diary
Date AM/PM PEF Trigger Symptoms Quick-relief
medicine and response
Red zone visit
to doctor/hospital?





3:50 a.m.

3:00 p.m.



Improved PEF





Eliminated wheezing


Click here for a
blank asthma diary template (What is a PDF document?).

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ByHealthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD – Internal Medicine
Adam Husney, MD – Family Medicine
Specialist Medical Reviewer Rohit K Katial, MD – Allergy and Immunology

Current as ofMarch 25, 2017