Measuring your peak flow before and after exposure to a possible asthma trigger, such as something you're allergic to or a substance you're exposed to at work, may also show if anything in particular causes your symptoms. It can also check if your medication is working, and indicate whether you're having an asthma attack. Your score can show whether or not your condition is getting worse.

If you've already been diagnosed with asthma, measuring your peak flow regularly can be a useful way of monitoring your condition. This could be a sign that you have asthma, although other tests such as spirometry will often be needed to confirm the diagnosis. Why peak flow is measuredīy measuring how fast you're able to breathe out, your peak flow score can indicate whether your airways are narrowed. These are available on prescription or can be bought from most pharmacies. Or they may be artificially low due to not enough effort or poor technique.A peak flow test involves blowing as hard as you can into a small handheld device called a peak flow meter. Numbers can be artificially high with tongue thrusts or spitting. Be sure to bring it to your asthma check-ups.Ī peak flow reading will only be as good as your effort.

Your Asthma Action Plan may tell you to take your peak flow reading more often and to adjust your medicines.

A decrease in peak flow of 20 to 30 percent of your personal best may mean the start of an asthma episode.

Write down your peak flow number in your asthma diary every day.

What Are Some Important Things to Remember?

Your Asthma Action Plan should provide clear instructions. If you cannot reach your doctor and your peak flow stays in the red zone, go directly to the emergency room. Call your doctor immediately if your peak flow number does not return to the yellow or green zone and stay in that zone. You must take your quick-relief medicine right away. Red Zone (below 50 percent of your personal best number) signals a medical emergency. Follow your Asthma Action Plan and seek additional medical care as indicated. Your doctor may need to change your Asthma Action Plan. Or your overall asthma may not be under control. You may be having an asthma episode that requires an increase in your medicines or the addition of new medicines. You should take a quick-relief medicine and check to see if your peak flow returns to the green zone. Yellow Zone (50 to 80 percent of your personal best number) signals caution. Take your daily controller medicines (if prescribed), as usual. Green Zone (80 to 100 percent of your personal best number) signals all clear. This will help you know what to do when your peak flow number changes. It is easiest if these target zones are added to your Asthma Action Plan. The peak flow numbers are put into a chart with zones that are set up like a traffic light. Once you know your personal best peak flow number, your doctor will give you a range of numbers that tell you what to do. When you get a new peak flow meter, even if it is the same kind as you have used in the past.Before and after taking quick-relief medicine.When you wake up and between noon and 2 p.m.At least two times a day for two to three weeks.To find out your personal best peak flow number, take peak flow readings: Your Asthma Action Plan needs to be based on your personal best peak flow number. Good control is when you feel good and do not have any asthma symptoms.Įveryone’s asthma is different, so your best peak flow may be different from the average number for someone of your height, weight and gender. Your personal best peak flow number is the highest peak flow number you have over a two- to three-week period when your asthma is under good control. Write down the highest of the three numbers in your asthma diary.Immediately repeat steps 1 through 6 two more times.Blow into the meter again and get a new reading. But if you cough as you use the meter or make a mistake, don’t use that number. Blow out as hard and fast as you can in a single blow.Do not let your tongue block the hole in the mouthpiece. Place the meter in your mouth between your teeth and close your lips around the mouthpiece.Place the indicator at the base of the numbered scale.Remember to always use the same peak flow meter.

You might have to check it more often if you are having more episodes than usual, or if your reading is below 80 percent of your personal best. Measure your peak flow at least once a day, usually in the morning before you take your asthma medicines. Identify triggers (things that cause asthma symptoms)īetter understand and talk about your asthma Decide if your Asthma Action Plan is working wellĭecide when to add, increase or even stop a medicine

Peak flow meter readings