How to Find Your Best Peak Flow Number

Your best number is the highest number you can have over two to three weeks. You should take these numbers only when your asthma is in good control. Good control means you don't now have any signs of asthma.

Each person's asthma is different, and each person's best number is different. Even among people who are the same height, weight and sex, numbers can differ.

Here's how to determine your best peak flow number:

• Use the meter at least two times a day for two to three weeks.
• Use the meter when you wake up. Use it again between noon and 2 p.m.
• If you use medicine to help you breathe, use the meter before and after you use this medicine.

Talk to your doctor before you use the meter. Your doctor may have other instructions.

Once you know your personal best number, you can use this tool. Or you may ask your doctor to help find your Green, Yellow and Red Zones.

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