This is the 2nd installment of my “ Breathing, the mini series“. This one is more for the non-asthmatics out there, but I think some of our lung challenged friends might learn a thing or two as well.
If you hang around asthmatics or browse as many personal asthma blogs as much as I do, then you’ve undoubtedly stumbled across phrases or symbols like “Green Zone” “ Yellow Zone ” ” Red Zone”… Pfs and the like. To the lay person, these terms might just sound like a flowery way for an asthmatic to describe how they’re breathing at a particular time. In many cases however, these terms are not only used as subjective representations of how an asthmatic might characterize their breathing, but they also represent actual physical measurements from a device used to measure lung function.
Most of us ( if we are wise) use a simple, but accurate tool called a peak flow meter to measure our basic lung function. Peak flow meters work by measuring how fast one can exhale a single full breath. The test result is usually displayed in (lpm) liters per minute and is surprisingly accurate if done correctly. The resulting value, usually a number between 300-600, gives us an accurate reflection of how constricted or obstructed our lungs might be at that moment. The lower the number is, the more obstructed your lungs are and the more difficult it is to breath. The higher the number, the less obstructed and the easier it is to breath.
Because lungs come in difference sizes, shapes and genders, peak flow numbers and ranges will be slightly different for each person. What might be a normal peak flow value for one person, might be an abnormal value for someone else. Normal predicted values are based on age, height , weight and sex, but all this is not important. What is important, is that you determine what your peak flow number is when you’re feeling at your best. This is called your personal best or baseline peak flow . This is the number by which all other peak flow comparisons are made.
Your personal best pf is determined by taking a measurement when you’re breathing at your very best, preferably averaged over several weeks and with no symptoms and /or after taking an inhaler or nebulizer treatment.
The next thing we do is mark our peak flow zones: Peak flow zones are based on your personal best peak flow number. The zones will help you monitor your asthma and take the right actions to keep it under control. The colors used with each zone come from the traffic light ( which btw yours truly made popular).
The result will look something like this:
Here are my personal peak flow zones: (Over the years my personal best pf has dropped from 550 to 350)
Green Zone 300 or greater
Yellow Zone 299-210
Red Zone 209 or less
So why do you need a medical device to tell you if you’re short of breath? Well, believe it or not, there are some asthmatics out there ( myself included), who are not always aware of subtle changes in their breathing. We’re known as poor- perceives or under-perceivers. For us, using a peak flow meter on a regular, and sometimes frequent basis, is crucial for getting a better handle on what’s actually going on with our lungs.
On the opposite end of the spectrum you have what they call over-perceivers. These are folks who are extremely sensitive to even minute changes in breathing pattern. These people should use their peak flow meter to verify whether what they’re feeling is actually being reflected in their peak flow readings. They’re are times when you can feel like and elephant is sitting on your chest, only to find that your peak flow readings are completely normal or just a little off. That’s because our brain and lungs are sometimes not on the same page. This mismatch in sensation vs PF readingx can also occur when the smaller airways are constricted or there is air trapping present, as PF readings are more reflective of large airway function than of the smaller airways.
Most asthmatics fall somewhere in the middle, and for them peak flows are usually done on an as needed basis or when they have symptoms.
Well, there you have it. The next time you hear an asthmatic talk about their breathing zones, hopefully you’ll have a better idea of just what the heck they’re talking about….yellow, green , red.. and all those weird zony things.
If you’d like to learn more about the asthma zones, in particular the yellow zone, check out this post I wrote a few years back.