Peak flow meter and asthma: what to know

Your clinician may help you establish a personal best when your asthma is well controlled. Later readings are compared with that baseline and with the zones in your action plan. Technique, effort, posture, time of day, and the meter itself can affect results. Cough, wheeze, chest tightness, or breathlessness can matter even when a single reading seems reassuring. A pattern of falling readings deserves attention.

Stand or sit upright, reset the marker, take a full breath, seal your lips around the mouthpiece, and blow out once as hard and fast as you can. Repeat the blow several times as instructed and record the highest reliable result rather than adding the readings together. Use the same meter and method each time. Keep the mouthpiece clean according to its instructions, and bring the record to appointments.

Follow your written asthma action plan when readings fall into its caution or emergency zone. Seek urgent help if breathing becomes severely difficult, you cannot speak comfortably, your lips look blue or grey, you become unusually drowsy, or reliever treatment is not helping. Do not delay emergency care while repeating measurements. Wheezing, cough, and chest tightness may accompany an asthma flare.

Ask which meter is suitable, how to find your personal best, how often to measure, and which readings should change your treatment. Clarify how to use your reliever and preventer inhalers, when to arrange a review, and whether allergies or a chronic cough could be affecting your breathing.