Reasons for peak flow measurements


Why you should measure your peak flow if you have asthma or chronic bronchitis

Peak flow is the maximum air flow in a strong exhalation. Taking regular peak flow measurements is helpful in monitoring respiratory diseases such as asthma and chronic bronchitis. This allows doctors and patients to detect possible triggers of asthma attacks – such as allergies or dust – early on and to decide on proper treatment.

Modern plans for monitoring asthma always require a peak flow monitor. This device gives patients better, faster and more objective information about their breathing problems than other methods – even before wheezing and coughing fits occur.

When should measurements be taken?

Taking a regular peak flow measurement is important to monitor your condition. Doctors generally recommend taking daily measurements once in the morning and once in the evening. The measurements should also be taken:

  • When you feel bad
  • When you have shortness of breath
  • Always before taking prescribed medication

What you should pay attention to in a peak flow measurement

Your doctor is only interested in the HIGHEST measured value that you get from a series of measurements. Please repeat the measurements if you think you could get a better result for that session. Please inform you doctor if the values worsen from measurement to measurement. This could be a sign of unstable asthma.

A coughing fit during a measurement can lead to a false reading (too low), so you should always repeat the measurement if this happens. If you want to take several measurements in a row, make sure to rest sufficiently after each reading. This is the only way to get precise measurements.

Please note that a low peak value can indicate an imminent asthma attack - even if you have no other symptoms!


  • Your doctor is only interested in the highest value
  • Repeat measurements to get the best possible result
  • Inform your doctor if your values worsen
  • Coughing fits can give false results – repeat the measurement!
  • Rest sufficiently between taking measurements
  • Low peak flow values are a sign of an upcoming asthma attack (even without other symptoms)