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Instructions for Determining Your Personal Best Peak Flow Number

Your personal best peak flow number is the highest peak flow number you can measure over two to three weeks. You should take these measurements only when your asthma is in good control. Good control means you don't currently have any symptoms of asthma.

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

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

• Take peak flow readings at least two times a day for two to three weeks.
• Take the readings when you wake up and again between noon and 2 p.m.
• If you use quick-relief medication, take the readings before and after you use this medicine.

Talk to your doctor before measuring your personal best peak flow number. He or she may have other instructions or suggestions, based on your condition.

Once you know your personal best peak flow number, you can use this calculator or ask your doctor to help determine the values for your Green, Yellow and Red Zones.

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