What you can expect

To start, your doctor will want to get an idea of your peak flow measurements when you feel good and have no asthma symptoms.

You'll record your daily peak flow rate over a two- to three-week period. Your highest peak flow rate over this period is known as your "personal best." Your personal best serves as a benchmark in your daily asthma management plan.

When to check your peak flow

If your asthma is well-controlled, you may decide to only use it when you feel your asthma is getting worse. If your asthma isn't very well-controlled, you may need to take peak flow readings more than once a day. Talk with your doctor about how often you should use your peak flow meter.

In addition to regular peak flow monitoring, you may need to check your peak flow in these situations:

• You have asthma symptoms that wake you up at night.
• You have increased symptoms during the day.
• You have a cold, flu or other illness that affects your breathing.
• You need to use quick-relief (rescue) medication, such as inhaled albuterol. (Check your peak flow before you take rescue medication. Then check it again after 20 or 30 minutes.)

Tracking your readings

Record your peak flow rate in an asthma diary. Some people record their peak flow meter readings by hand.

If you have an electronic personal health record, you may choose to enter your information into the record using a computer or mobile device. This gives you the option of sharing your data with your health care professionals and family members. Some peak flow meters upload this data automatically.