A man is using a peak flow meter while a doctor observes
Using a peak flow meter for COPD is a critical part of your treatment. It helps by measuring lung function and how air flows from your lungs.

Why Using a Peak Flow Meter for COPD Is Important

If you have been diagnosed with chronic obstructive pulmonary disease (COPD), it’s important to know what COPD is and how you can control your condition.

Using a peak flow meter for COPD is a critical part of your treatment, and you’re the one responsible for using it correctly – so that you get the correct treatment.

What Is COPD?

COPD is a general term that describes a group of lung diseases including asthma, chronic bronchitis, emphysema, and bronchiectasis. With each one of these conditions, the primary symptom is increasing breathlessness – difficulty breathing.


Signs and symptoms of COPD are:

  • Chest tightness
  • Increased breathlessness
  • Frequent coughing
  • Wheezing

Most cases of COPD occur because of inhaled pollutants – smoking, second-hand smoke, fumes, chemicals, and dust. These may be indoors or outdoors.

Genetics can also play a role in an individual’s development of COPD—even if the person has never smoked or has ever been exposed to strong lung irritants in the workplace.

Controlling COPD

Your doctor will talk to you about changes you will need to make in your everyday life – including small changes that can significantly impact your breathing, and prevent symptoms.

Several medicines can help in the treatment of COPD. Some are taken as pills or capsules, while others are inhaled.

Controller medications meant to work in the long term, keeping your lungs open to improve your breathing while you’re active. Rescue inhalers provide quick relief when your lungs get tight to avoid emergencies.

What is a Peak Expiratory Flow Rate Test?

The peak expiratory flow rate (PEFR) test measures how fast you can exhale and is also referred to as a peak flow test. It is commonly performed at home with a peak flow monitor.

Keeping ongoing records of your flow rate is important. This is the only way to ensure you notice patterns when your flow rate is low or decreasing.

For example, when you notice these patterns you can take steps to prevent your symptoms from worsening into a full-blown asthma attack. You can adjust your medication or change environmental factors that affect your breathing.

When Does a Doctor Recommend a Peak Expiratory Flow Rate Test?

The PEFR test is used to check for lung problems:

  • Asthma
  • COPD
  • Transplanted lung

How to Use a Peak Flow Monitor for COPD

You’ll use a peak expiratory flow monitor to perform the test. This handheld instrument has a mouthpiece on one end and a scale on the other end.

You will blow air into the mouthpiece, which causes a small plastic arrow to move. This measures the airflow speed.

To take the test, you will:

  1. Breathe in as deeply as you can.
  2. Blow into the mouthpiece as quickly and as hard as you can.
  3. Do not put your tongue in front of the mouthpiece.
  4. Do the test three times.
  5. Note the highest speed of the three.

If you cough or sneeze while breathing out, you will need to start again.

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How Often Do You Need to Take This Test?

You should measure your peak flow rate:

  • Twice a day for two to three weeks.
  • When you wake up in the morning and the late afternoon or early evening.
  • 15 to 20 minutes after using an inhaled, quick-acting beta2-agonist.

A beta2-agonist medication is a medication that relaxes the muscles surrounding the airways helping them to expand. Albuterol (Proventil and Ventolin) is a beta2-agonist.

Test results are classified as green, yellow, and red zones:

  • Green zone: 80 to 100 percent of your usual flow rate. This is the ideal zone and considered to be a normal peak flow reading. It means your condition is under control.
  • Yellow zone: 50 to 80 percent of your usual flow rate. Your airways may be starting to narrow. Talk to your doctor about how to handle yellow zone results.
  • Red zone: less than 50 percent of your normal rate. Your airways are severely narrowing. Take your rescue medications and contact emergency services.

You can compare your past COPD peak flow meter readings to determine your category.

When Your Results are Abnormal

When your airways are blocked, your flow rate is weaker.

If you notice a significant fall in your peak flow speed, it may be caused by a flare-up of your lung disease. People with asthma may experience low peak flow rates before they develop breathing symptoms.

If you have any of these symptoms, go to the emergency room immediately:


  • Fast breathing and straining chest muscles to breathe
  • Severe anxiety or panic caused by the inability to breathe
  • Sweating
  • Rapid pulse
  • Shortness of breath
  • Worsening cough
  • Wheezing or raspy breathing
  • Unable to speak more than short phrases
  • Decreased alertness
  • Bluish color to the face or lips

Check with your doctor to get a more accurate reading with a spirometer, a more advanced peak flow monitoring device. This test involves breathing into a mouthpiece which is connected to a machine that measures your breathing rates.

It is critical that you regularly monitor your flow rate to avoid emergencies.

COPD can be life-threatening if not treated properly. Work closely with your doctor to make sure you’re conducting the peak flow test correctly – and that you get treated if you have abnormal results.