Skip Ribbon Commands
Skip to main content
 
Health Issues

How to Use a Peak Flow Meter to Care for Kids with Asthma

Click here to insert a picture from SharePoint. Click here to insert a picture from SharePoint.

​By: Clinton Dunn MD, FAAP & Addie Dodson, MD, FAAP

Children with asthma need extra care to stay healthy. They may struggle to breathe after a burst of exercise, an emotional shock or exposure to an asthma trigger.

Having a peak flow meter on hand can help you measure your child's breathing to see if they need special medicines or emergency attention. A peak flow meter also helps you track your child's breathing over time to determine what's normal for them (and what's not).

Here's a quick guide to peak flow meters and how to use them as part of your child's asthma action plan.

What is a peak flow meter?

A peak flow meter is a small, hand-held device that measures how quickly your child can push air out of their lungs when they blow out as hard as they can. (This number equals your child's "peak flow" at the time of measurement.)

Peak flow meters are generally used with children 4 years or older. Over time, you can teach your child how to take their own readings.

A manual peak flow meter has marks on the side that indicate your child's peak flow. A digital meter displays the number on a screen. Either type of meter can help you keep track of your child's breathing over time—or figure out what to do when asthma symptoms get worse.

What do the numbers on the peak flow meter mean?

For kids with asthma, peak flow readings are usually taken at each medical visit. This helps your child's care team establish a baseline score, measuring how they breathe on healthy, symptom-free days.

This "personal best" score becomes part of your child's asthma action plan so you (and other caregivers) can compare it to what's happening at any given time and administer meds or seek emergency care.

Using a peak flow meter to measure your child's breathing

Your pediatrician or asthma specialist may ask you to take peak flow readings once or twice a week to create a detailed record of your child's breathing. (This free asthma action tracker can help.)

How to do a peak flow reading:

  • Make sure the meter is set to zero.

  • Ask your child to stand up straight.

  • Have them take a big, deep breath, then close their lips around the mouthpiece.

  • Ask them to blow out as hard and fast as they can.

  • Write down the peak flow reading.

If you're measuring peak flow as part of regular tracking, you should repeat the test 2 or 3 times, then record the highest score.

How peak flow scores work with your child's asthma action plan

Your child's asthma action plan uses a "traffic light" system to help you interpret peak flow scores—and, if needed, get medical attention.

  • A score in the Green Zone means breathing is about 80% to 100% of your child's healthy flow. Make sure they get their Green Zone (controller) medications, but no other steps are needed.

  • A score in the Yellow Zone (about 50% to 80% of healthy peak flow) means your child could be heading for an asthma flare-up. They need controller medicines plus quick-relief medications to reduce symptoms.

  • A score in the Red Zone (less than 50% of healthy peak flow) shows your child may be in danger. Follow the emergency steps in the action plan.

Peak flow scores are just one sign of an asthma flare-up

Other signs of an asthma attack include:

  • Fast, shallow breathing

  • Coughing

  • Tightness in the chest

  • Wheezing (a sound like a whistle) when your child breathes

  • Flared nostrils with every breath

  • Skin between the ribs sinks in with each breath

  • Your child can't speak and may not be able to walk

Remember that when asthma flares up, seconds count.

If your child is in the Red Zone, call your pediatrician or asthma specialist right away. If they can't talk, can't walk or seem disoriented, call 911 or go to the closest emergency room.

Make sure your child's school, athletic coaches, camp guides and other caregivers have copies of the asthma action plan and know how to handle an emergency.

Partner with your pediatrician or asthma specialist to control your child's asthma

Managing asthma can be challenging, but with the right support, your child can enjoy an active, healthy life. Whenever you have questions about your child's breathing—or any part of their wellbeing—ask your pediatrician for help.

More information


About Dr. Dunn

Clinton Dunn, MD, FAAPClinton Dunn, MD, FAAP, is a board-certified pediatrician and allergist/immunologist who practices in the Hampton Roads Virginia area. He is a member of the American Academy of Pediatrics (AAP) and the AAP Section on Allergy and Immunology. His clinical interests focus on atopic dermatitis, asthma, food allergy and applying high quality evidence-based medicine for the improvement of pediatric allergic/immunologic diseases.

About Dr. Dodson

Addie Dodson, MD, FAAPAddie Dodson, MD, FAAP, is a board-certified pediatrician and currently completing her fellowship in pediatric pulmonology at Children's Hospital Los Angeles. Dr. Dodson is a member of the AAP its Section on Pediatric Pulmonology and Sleep Medicine. She currently serves as the section's executive committee fellow-in-training liaison. Dr. Dodson's clinical interests within pulmonology are growing while she continues in her fellowship, but she has special interests in asthma, use of technology to improve practice, medical education and advocacy.

Last Updated
3/24/2025
Source
American Academy of Pediatrics Section on Allergy and Immunology (Copyright © 2025)
The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.
Follow Us