Measuring your peak flow rate

1. Measuring Your Peak Flow Rate
A peak flow meter is a portable, inexpensive, hand-held device used to measure how air
flows from your lungs in one “fast blast.” In other words, the meter measures your ability to
push air out of your lungs.
Peak flow meters may be provided in two ranges to measure the air pushed out of your lungs.
A low range peak flow meter is for small children, and a standard range peak flow meter is
for older children, teenagers and adults. An adult has much larger airways than a child and
needs the larger range.
There are several types of peak flow meters available. Talk to your healthcare provider or
pharmacist about which type to use.
Who Can Benefit From Using A Peak Flow Meter?
Many healthcare providers believe that people who have asthma can benefit from the use of a
peak flow meter. If you need to adjust your daily medication for asthma, a peak flow meter
can be an important part of your asthma management plan.
Patients age 5 and older are usually able to use a peak flow meter to help manage their
asthma. In addition, some people with chronic bronchitis and emphysema may also benefit
from the use of a peak flow meter.
Not all healthcare providers use peak flow meters in their management of children and adults
with asthma. Many healthcare providers believe a peak flow meter may be of most help for
people with moderate and severe asthma. If your asthma is mild or you do not use daily
medication, a peak flow meter may not be useful for asthma management.
Why Should I Measure My Flow Rate?
Your peak flow rates can show you if your asthma is getting worse, even before you feel
symptoms. In addition, measurements with a peak flow meter can help your healthcare
provider make decisions about your treatment and adjust your medicines as necessary.
A peak flow meter can be used as a signal of when your asthma is getting worse. Asthma
sometimes changes gradually. Your peak flow may show changes before you feel them. Peak
flow readings can show you when to start following the steps on your asthma action plan that
you developed with your healthcare provider. It can help you determine the severity of the
episode; decide when to use your rescue medicine; and decide when to seek emergency care.
A peak flow meter may help you and your healthcare provider identify causes of your asthma
at work, home or play. It may help parents to determine what might be triggering their
child’s asthma.
How Do You Use A Peak Flow Meter?
Step 1: Before each use, make sure the sliding marker or arrow on the Peak Flow Meter is at
the bottom of the numbered scale (zero or the lowest number on the scale).

2. Step 2: Stand up straight. Remove gum or any food from your mouth. Take a deep breath (as
deep as you can). Put the mouthpiece of the peak flow meter into your mouth. Close your lips
tightly around the mouthpiece. Be sure to keep your tongue away from the mouthpiece. In
one breath, blow out as hard and as quickly as possible. Blow a “fast hard blast” rather than
“slowly blowing” until you have emptied out nearly all of the air from your lungs.
Step 3: The force of the air coming out of your lungs causes the marker to move along the
numbered scale. Note the number on a piece of paper.
Step 4: Repeat the entire routine three times. (You know you have done the routine correctly
when the numbers from all three tries are very close together.)
Step 5: Record the highest of the three ratings. Do not calculate an average. This is very
important. You can’t breathe out too much when using your peak flow meter but you can
breathe out too little. Record your highest reading.
Step 6: Measure your peak flow rate close to the same time each day. You and your
healthcare provider can determine the best times. One suggestion is to measure your peak
flow rate twice daily between 7 and 9 a.m. and between 6 and 8 p.m. You may want to
measure your peak flow rate before or after using your medicine. Some people measure peak
flow both before and after taking medication. Try to do it the same way each time.
Step 7: Keep a chart of your peak flow rates. Discuss the readings with your
healthcare provider.
How Do I Chart My Peak Flow Rates?
Chart the HIGHEST of the three readings. This is called, “your personal best”. The chart
could include the date at the top of the page with AM and PM listed. The left margin could
list a scale, starting with zero (0) liters per minute (L/min) at the bottom of the page and
ending with 600 L/min at the top.
You could leave room at the bottom of the page for notes to describe how you are feeling or
to list any other thoughts you may have.
What Is A “Normal” Peak Flow Rate?
A “normal” peak flow rate is based on a person’s age, height, sex and race. A standardized
“normal” may be obtained from a chart comparing the patient with a population without
breathing problems.
A patient can figure out what is normal for them, based on their own peak flow rate.
Therefore, it is important for you and your healthcare provider to discuss what is considered
“normal” for you.
Once you have learned your usual and expected peak flow rate, you will be able to better
recognize changes or trends in your asthma.
How Can I Determine A “Normal” Peak Flow Rate For Me?

3. Three zones of measurement are commonly used to interpret peak flow rates. It is easy to
relate the three zones to the traffic light colors: green, yellow, and red. In general, a normal
peak flow rate can vary as much as 20 percent.
Be aware of the following general guidelines. Keep in mind that recognizing changes from
“normal” is important. Your healthcare provider may suggest other zones to follow.
Green Zone:
80 to 100 percent of your usual or “normal” peak flow rate signals all clear. A reading in this
zone means that your asthma is under reasonably good control. It would be advisable to
continue your prescribed program of management.
Yellow Zone:
50 to 80 percent of your usual or “normal” peak flow rate signals caution. It is a time for
decisions. Your airways are narrowing and may require extra treatment. Your symptoms can
get better or worse depending on what you do, or how and when you use your prescribed
medication. You and your healthcare provider should have a plan for yellow zone readings.
Red Zone:
Less than 50 percent of your usual or “normal” peak flow rate signals a Medical Alert.
Immediate decisions and actions need to be taken. Severe airway narrowing may be
occurring. Take your rescue medications right away. Contact your healthcare provider now
and follow the plan he has given you for red zone readings.
Some healthcare providers may suggest zones with a smaller range, such as 90 to 100
percent. Always follow your healthcare provider’s suggestions about your peak flow rate.
Asthma Action Plan Based on Peak Flow Readings
It is important to know your peak flow reading, but it is even more important to know what
you will do based upon that reading. Work with your healthcare provider to develop an
asthma action plan that follows your green-yellow-red zone guidelines.
Record the peak flow readings that your healthcare provider recommends for your green
zone, yellow zone, and red zone. Then work out with your healthcare provider what you plan
to do when your peak flow falls in each of those zones.
When Should I Use My Peak Flow Meter?
Use of the peak flow meter depends on a number of things. Its use should be discussed with
your healthcare provider.
If your asthma is well controlled and you know the “normal” rate for you, you may decide to
measure your peak flow rate only when you sense that your asthma is getting worse. More
severe asthma may require several measurements daily.

4. Don’t forget that your peak flow meter needs care and cleaning. Dirt collected in the meter
may make your peak flow measurements inaccurate. If you have a cold or other respiratory
infection, germs or mucus may also collect in the meter.
Proper cleaning with mild detergent in hot water will keep your peak flow meter working
accurately and may keep you healthier.
American Lung Association
55 W. Wacker Drive, Suite 1150
T: 1-800-LUNGUSA | F: 202-452-1805 | E: [email protected]

5. Tests and Procedures
Peak flow meter
By Mayo Clinic Staff
A peak flow meter is a portable, easy-to-use device that measures how well your lungs are
working. If you have asthma, your doctor may recommend that you use a peak flow meter to
help track your asthma control.
In addition to watching for worsening signs and symptoms, such as wheezing or coughing,
you can use a peak flow meter to help you decide when you need to act to keep your asthma
under control. Regular use of your peak flow meter can give you time to adjust your
medication or take other steps before your symptoms get worse. A peak flow meter can be
useful for adults and children as young as preschool age.
A peak flow meter allows you to measure day-to-day changes in your breathing. Using a peak
flow meter can help you:
 Track the control of your asthma over time
 Show how well your treatment is working
 Recognize signs of a flare-up before symptoms appear
 Know what steps to take when you have signs of an asthma flare-up
 Decide when to call your doctor or get emergency care
Work with your doctor to make sure you get the right type of peak flow meter. Peak flow
meters are available over-the-counter and can be purchased at a pharmacy. There are several
types of peak flow meters available, and all of them work basically the same way: You blow
a fast, hard breath into a mouthpiece and record the resulting score. However, there are a few
differences.
 Meters designed for young children have a lower scale than do those designed for older
children, teens and adults. Some peak flow meters can be adjusted to work for either a
young child or an older child, teen or adult.
 Basic peak flow meters are inexpensive, simple to use and give accurate readings that you
must record in a peak flow diary.
 More expensive electronic peak flow meters record and track peak flow readings
automatically.
Using your peak flow meter
Here's the correct way to use a peak flow meter:
1. Move the marker to the bottom of the numbered scale, and connect the mouthpiece to the
peak flow meter (if it isn't already connected).
2. Stand up if you're able.
3. Take a deep breath, filling your lungs completely.
4. Place your lips tightly around the mouthpiece. Blow as hard and as fast as you can with a
single breath.
5. Note the final position of the marker. This is your peak flow rate.

6. 6. Follow the steps above then blow into the peak flow meter two more times. Record the
highest reading of the three.
To get accurate readings, make sure you know how to use your peak flow meter properly.
Ask your doctor or other health care provider to watch you use it. It's also important to keep
your peak flow meter clean. Follow the manufacturer's instructions — most peak flow meters
require weekly cleaning with warm water and a mild detergent.
To start, your doctor will want to get an idea of your peak flow measurements when you feel
good and have no asthma symptoms.
Measurements from a peak flow meter are called your peak flow rate. You'll record your
daily peak flow rate over a two- to three-week period. Your highest peak flow rate over this
period is known as your "personal best." Your personal best serves as a benchmark in your
daily asthma management plan.
When to check your peak flow
Your doctor will probably recommend using your peak flow meter once a day — typically
before you take your regular asthma medication in the morning.
If your asthma is under control most of the time, your doctor may say it's OK to check your
peak flow every few days instead of every day. If your asthma isn't very well controlled, you
may need to take peak flow readings more than once a day.
In addition to regular peak flow monitoring, you may need to check your peak flow in these
situations:
 You have asthma symptoms that wake you up at night.
 You have increased symptoms during the day.
 You have a cold, flu or other illness that affects your breathing.
 You need to use quick-relief (rescue) medication, such as inhaled albuterol. (Check your peak
flow before you take rescue medication. Then check it again after 20 or 30 minutes.)
Tracking your readings
Record your peak flow rate in an asthma diary. Some people record their peak flow meter
readings by hand. But if you have an electronic personal health record, you may choose to
enter your information into the record using a computer or mobile device. This gives you the
option of sharing your data with your health care providers and family members. Some peak
flow meters upload this data automatically.
Once you and your doctor have established your peak flow zones, you'll use a color-coded
system based on your symptoms and your peak flow. This system tells you what to do when
you are in each zone.
Green, yellow and red: Understanding your peak flow zones

7. Your doctor will use your personal best to set your peak flow zones. Each zone is determined
by your peak flow rate and symptoms. The color code for each zone reflects progressively
more-severe symptoms:
Green zone = stable
 Your peak flow rate is 80 to 100 percent of your personal best, an indication that your
asthma is under control.
 You probably have no asthma signs or symptoms.
 Take your preventive medications as usual.
 If you consistently stay within the green zone, your doctor may recommend reducing your
asthma medication.
Yellow zone = caution
 Your peak flow rate is 50 to 80 percent of your personal best, an indication that your asthma
is getting worse.
 You may have signs and symptoms such as coughing, wheezing or chest tightness - but your
peak flow rates may decrease before symptoms appear.
 You may need to increase or change your asthma medication.
Red zone = danger
 Your peak flow rate is less than 50 percent of your personal best, an indication of a medical
emergency.
 You may have severe coughing, wheezing and shortness of breath. Stop whatever you're
doing and use a bronchodilator or other medication to open your airways.
 Your asthma action plan will help you decide whether to call your doctor, take an oral
corticosteroid or seek emergency care.
Peak flow: Just one tool for asthma control
Using a peak flow meter can be an effective tool for managing your asthma — but there are
other things you need to do:
 Use an asthma action plan. An action plan is a simple but important part of managing your
asthma. It helps you keep track of which medications to take, when to take them and what
doses you need, based on whether you're in your green, yellow or red zone.
 Meet with your doctor. Even if your asthma's under control, meet with your doctor on a
regular basis to review your action plan and revise it as needed. Asthma symptoms change
over time, which means your treatment may need to change, too.
 Avoid your triggers. Pay attention to things that trigger your asthma symptoms or make
them worse and try to avoid them.
 Make healthy choices. Taking steps to stay healthy — for example, maintaining a healthy
weight, getting regular exercise and not smoking — can make a big difference in reducing
your asthma symptoms.
References

8. 1. Measuring your peak flow rate. American Lung Association. http://www.lungusa.org/lung-
disease/asthma/living-with-asthma/take-control-of-your-asthma/measuring-your-peak-
flow-rate.html. Accessed Dec. 22, 2011.
2. Expert panel report 3 (EPR-3): Guidelines for the diagnosis and management of asthma.
Bethesda, Md.: National Institutes of Health.
http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.htm. Accessed Dec. 22, 2011.
3. Tips to remember: Peak flow meter. American Academy of Allergy Asthma & Immunology.
http://www.aaaai.org/patients/publicedmat/tips/whatispeakflowmeter.stm. Accessed Dec
22, 2011.
Mar. 20, 2012
Original article:
http://www.mayoclinic.org/tests-procedures/peak-flow-meter/basics/definition/prc-20013057
.
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9. Peak Expiratory Flow Rates

child and adolescent female: 6 - 20 years of age
Height (in) 42 46 50 54 57 60 64 68 72
Age: 6 134 164 193 223 245 268 297 327 357
8 153 182 212 242 264 287 316 346 376
10 171 201 231 261 283 305 335 365 395
12 190 220 250 280 302 324 354 384 414
14 209 239 269 298 321 343 373 403 432
16 228 258 288 318 340 362 392 421 451
18 247 277 306 336 358 381 411 440 470
20 266 295 325 355 377 400 429 459 489
child and adolescent male: 6 - 25 years of age
Height (in) 44 48 52 56 60 64 68 72 76
Age: 6 99 146 194 241 289 336 384 431 479
8 119 166 214 261 309 356 404 451 499
10 139 186 234 281 329 376 424 471 519
12 159 206 254 301 349 396 444 491 539
14 178 226 274 321 369 416 464 511 559
16 198 246 293 341 389 436 484 531 579
18 218 266 313 361 408 456 503 551 599
20 238 286 333 381 428 476 523 571 618
22 258 306 353 401 448 496 543 591 638
24 278 326 373 421 468 516 563 611 658
25 288 336 383 431 478 526 573 621 668

10. adult female: 20 - 80 years of age
Height (in) 58 60 62 64 66 68 70
Age: 20 357 372 387 402 417 432 446
25 350 365 379 394 409 424 439
30 342 357 372 387 402 417 431
35 335 350 364 379 394 409 424
40 327 342 357 372 387 402 416
45 320 335 349 364 379 394 409
50 312 327 342 357 372 387 401
55 308 320 334 349 364 379 394
60 297 312 327 342 357 372 386
65 290 305 319 334 349 364 379
70 282 297 312 327 342 357 371
75 275 290 304 319 334 349 364
80 267 282 297 312 327 342 356
adult male: 25 - 80 years of age
Height (in) 63 65 67 69 71 73 75 77
Age: 24 492 520 549 578 606 635 664 692
30 481 510 538 567 596 624 653 682
35 471 499 528 557 585 614 643 671
40 460 489 517 546 575 603 632 661
45 450 478 507 536 564 593 622 650
50 439 468 496 525 554 582 611 640
55 429 457 486 515 543 572 601 629
60 418 447 475 504 533 561 590 619
65 408 436 465 494 522 551 580 608
70 397 426 454 483 512 540 569 598
75 387 405 444 473 501 530 559 587
80 376 405 433 462 491 519 548 577


http://www.sh.lsuhsc.edu/fammed/outpatientmanual/PeakFlowTables.htm