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  • Lexie

Check Your Breath: Common Chronic Illness Breathing Tests

Understanding breathing tests and why they are preformed is a way to advocate for your chronic illness. Educating yourself on the multiple options helps when managing your chronic illness.

Testing can be overwhelming due to the medical terminology that is not common speech, the fear of the unknown, and understanding the difficult anatomy & physiology.

It can also be confusing to understand what is being measured, why the test is being preformed, and how to interpret the results.

There is no way to shorten the education that those in the medical field obtain, and it would be nearly impossible to include all information needed for every possible outcome.

Simple tests, like measuring the lungs and how they function, is no exception. I can remember sitting through several lectures and still needing more study!

Let’s break down some basics of the respiratory tests that might be preformed in chronic illness.

picture of the respiratory system

Who Tests My Breath?

Pulmonology is the study of the respiratory tract.

It is considered a branch of internal medicine, and is also very closely related to critical care medicine.

We have to breathe to live, so this makes sense.

A Pulmonologist is the doctor that specializes in this area of expertise.

Parts Of The Respiratory System:

  • Lungs

  • Throat (pharynx)

  • Voice Box (Larynx)

  • Windpipe (Trachea)

  • Nose

  • Mouth

There are other specialties that may overlap, such as an ENT (ear, nose, and throat doctor).

Being referred to this speciality is usually because of an issue within the respiratory system or for critical care management.

Pulmonology Definitions:

Over the years with the addition of schooling, I kept notes on every topic I was learning.

Unfortunately, I did not write down every reference for each note that I took.

Please note that this information came from either a lecture, textbook, study group, lab, or online research. Definitions are difficult to put in your own words (it looses the meaning) so know that these are only an interpretation.

Tidal Volume TV: The amount of air inhaled or exhaled during normal breathing

Minute Volume MV: Total amount of air exhaled per minute

Vital Capacity VC: Total volume of air that can be exhaled after inhaling as much as you can

Functional Residual Capacity FRC: This is the amount of air left in the lungs after exhaling normally

Residual Volume: The amount of air left in the lungs when filled with as much air as possible

Forced Vital Capacity FVC: Amount of air exhaled forcefully and quickly after inhaling as much as you can

Forced Expiratory Volume FEV: Amount of air expired during the first second and third seconds of the FVC test

Forced Expiratory flow: The average rate of flow during middle half of FVC test

Peak Expiratory Flow Rate PEFR: The rate that you can force air out of your lungs

These definitions may be helpful when trying to figure out how to understand the results on your printed lab result.

One source to find these is from John Hopkins.

Types Of Breathing Tests:

Like with every other specialty, there are specific tests that measure different parts of our respiratory system.

Most Common Tests:

  • PFT’s Pulmonary Function Tests

  • MIP/MEP Minimum Inspiratory Pressure / Maximum Expiratory Pressure

  • Negative Inspiratory Force Meter

  • Pulse Oximetry

  • Peak Flow Meter

  • Spirometer

  • Single Breath Test Count

  • ABG’s Arterial Blood Gasses

  • X-Ray

This is not an inclusive list, but some of the most common tests I have seen questions about, or have had myself and can speak on personally.

The terminology can be confusing, so this breakdown will be in the most simplest form I can provide.

PFT’s: Pulmonary Function Tests

These tests show how well the lungs are working.

The measurements are lung volume, capacity, rates of flow, and gas exchange.

The machine or “box” used to do the test is called a Plethysmography.

They are performed by sitting (or standing) in an air tight box and using the instruments inside. The box I sat it was clear and had an elevator type feel to it.

Once you sit in the box, you will be instructed on what to do next. There is a mouthpiece that you will blow into or inhale from.

This test is not painful, but can cause some exhaustion if you have issues breathing already.

Your height, weight, age, sex, and previous tests are all a part of finding your normal values for your results.

There is not a set number that really works for everyone because we are all so different. Ranges are used based on this information.

You may have had to do this set of testing before surgery at some point.

Things you can do to prepare for this test are pretty basic.

You do want to make sure you speak with your doctor about what medications you are taking, and ask if you should take them prior to the test being completed so your results are more accurate.


This test measures the maximum strength of the respiratory muscles specifically.

MIP: Measures the strength of the muscles used during inspiration during normal and forced BREATHING IN

MEP: Measures the strength of the muscles that are used during normal and forced BREATHING OUT

The muscles used in breathing are the diagram, the abdominal muscles, and the intercostal (rib area) muscles.

Each muscle works on helping us breathe in or breathe out. This mechanism can be pretty complex.

The pressure when you breathe out as hard as you possible can is what defines the chest muscle strength.

This test is usually done a few times and does not take a lot of time.

When I had the test done, it was very similar to the PFT with a special attachment to the machine.

This attachment was not available at every office, so it may be something to mention when scheduling this appointment to ensure they have this special attachment.

I had difficulties making the seal around the mouthpiece due to wearing dentures and my muscle weakness.

Once I removed the dentures, I placed my fingers around my mouth and forced the seal to get a more accurate reading.

This test is what determined (after comparing to other normal values from the other tests) that I was experiencing issues with my breathing muscles versus my lungs and other respiratory structures.

NIF: Negative Inspiratory Force Meter

The NIF meter is a tool used for measuring the maximal inspiratory effort in the form of pressure that is generated against an occluded airway.

Basically, it feels like you are trying to suck a frozen milkshake out of a straw.

This is similar to the above MIP test.

Although this can be done at hospitals for critical care situations (like when to stop ventilation), you can have a version for your home. HERE is the link to purchase one. I am not affiliated with this company.

I have been to two different hospitals that do not carry this device. I carry mine with me in my hospital bag now because of this.

How To Use The NIF Meter:

Make sure nose is pinched! The seal is very important!

  1. Set Gauge to zero. Turn center knob counter clockwise so the orange indicator is below 60

  2. Use thumb to press down on occlusion knob and hold it here until end of test

  3. Exhale completely and then form a tight seal around mouthpiece ; then inhale deep as possible (it will feel like you are doing nothing… this is normal)

  4. Let go of occlusion knob and remove NIF from mouth

I struggled with the use of this meter and actually learned how to use mine from a nurse in a support group.

It was the most helpful information!

Pulse Oximetry

The pulse ox is probably one of the most common tools that those in the chronic illness community have heard of or used.

This is a painless meter that is applied to the finger. The test is less than a minute to preform.

It measures the oxygen saturation in a person’s blood. When the lungs cannot transport the oxygen to the blood the Oxygen saturation goes down.

pulse ox or pulse oximeter used for measuring heart rate and breathing in chronic illness

This test does not measure the carbon dioxide levels.

The normal values are around 95-100 in people who have no medical conditions. It is best to find your personal normal level with your doctor and then begin monitoring yourself.

Reasons A Pulse Oximeter May Be Less Accurate:

  • people with darker skin

  • skin temperature (cold hands)

  • nail polish or fake nails (it blocks the infrared light)

  • moving around too much

  • higher elevations

Most people are comfortable using this device as it is pretty straight forward.

These also include a heart rate reading on the top of the device.

These are fairly inexpensive.


My least favorite test to occur when visiting the pulmonologist is this one.

This is a blood test that measures the acidity or pH, and levels of oxygen and carbon dioxide from an artery instead of the vein.

Basically, it determines how well the person is moving oxygen into the blood, and how well the carbon dioxide is moving out of the blood.

These tests hurt. It is in an artery not a vein, so it doesn’t feel like a blood draw.

The pain is brief and is a stinging feeling. A needle is used to get a very small amount of blood from the artery.

Measurements need to be read by a medical professional!

The calculations are commonly interpreted wrong even amongst professionals and I won’t even attempt explaining them here.

This is a test that is more accurate than the pulse ox because it can measure the carbon dioxide.

There are conditions this test can help determine, including medical emergencies.

It is also used to see if therapies are working, like CPAP or BiPAP.

Peak Flow Meter

The Peak expiratory flow is the ability for someone to breathe the air out.

This test is portable and can be used at home. I just recently was given one when misdiagnosed with asthma.

The test is simple and causes no pain, only exhaustion for some. You use a mouthpiece and blow air into it.

The meter measures the force of air in liters per minute and has a scale inside of the meter.

How To Use A Peak Flow Meter:

This information came from a print out

  1. Move marker to the bottom of the numbered scale and connect the mouthpiece to the peak flow meter.

  2. Stand up

  3. Take a deep breath and fill the lungs

  4. Place lips around the mouthpiece and seal as good as possible

  5. Blow hard and fast

  6. See where the marker reads - this is your peak flow rate

  7. Do this three times and record highest of three readings

These are the zones listed on my specific meter.

Green zone = stable 80 - 100 percent

Yellow = caution 50 - 80 percent

Red = danger <50 percent

The meter was a little difficult to understand how to use and I had to follow the instructions given to me.


This imaging can be used like in other specialities to look at the body.

It may be helpful for your doctor to look and see if there is something “out of place” or to look for an abnormal growth or fluid.

These images can help direct the doctor to the next test, or because of their clinical experience, signal them to consider a diagnosis to evaluate.

I have had A LOT of these images done over the past nine years. They do not hurt and are fairly quick.


A spirometer measures the volume of air inspired and expired by the lungs. It measures ventilation (movement of air in and out of lungs)

Simply put, how much air you inhale and how much air you exhale is measured.

spirometer used for measuring breathing difficulties in chronic illness

Steps To Use A Spirometer:

  1. Sit down

  2. Put on your nose clip

  3. Take a Deep breath in and deep breath out for several seconds into the tube

  4. Test three times (you may become very tired)

  5. The test is usually less than fifteen minutes for test

  6. It measures FVC and FEV

You will be able to see the ball or floater move while you are preforming this test. This will “float” to the number on the device, or signal a reading (like seen below).

The spirometer can also keep lungs active and free of fluid and may be used for therapies like after surgery.

When you breathe slowly, the lungs inflate fully, so this may be something your doctor prescribes for you.

I was given one to bring home, but they are also located at the pulmonologist’s office and hospital. The picture below is one I have at home.

Single Breath Count

This test is very simple but very useful!

Count out loud after deeply inhaling (maximum inspiration). You want to reach 50 (this is considered a normal).

It is that simple!

You want to see how far you can count or if you can reach the number 50.

If it is less than 15, this indicates a very low FVC. This may warrant an emergency room visit and should be taken seriously. (I am instructed to seek care at a higher value, and your medical condition can effect when you need to be seen).

When I was diagnosed with my rare neuromuscular disease, this test became a helpful measurement for me to know, “when I need to go” to the hospital for my breathing difficulties.

What Test Do I Need?

The type of testing you need is determined by your medical condition, your symptoms, and your medical provider’s recommendation.

Keep in mind, all of these tests can be preformed in one visit and some combined. Other than the Peak Flow Meter, I preformed every test in one visit for my evaluation.

This was completely necessary after my shortness of breath had remained undetermined and unresponsive to medications.

There are other ways to check for breathing difficulties, but these tests seem to be the most commonly asked about amongst support groups or people in I have spoken with in the chronic illness community.

A perspective on testing I have developed, is that this creates my baseline.

Sometimes it is annoying that we have so many doctor visits and testing appointments to keep track of... I get it.

But, the more information we can gather, the better equipped the next physician viewing our cases will be.

This perspective comes from the many years of remaining undiagnosed.

MAKE SURE that ANY test you do, you ask for the copy of the results to store in your personal medical chart that you have created.

I like for my personal medical chart to tell my story in a medical and informational style that everyone can understand.

Amongst all of the issues that creep up on us with chronic illness, breathing is always going to be an important issue to address.

We have to breathe to live. Period.

Breathing Tools I have Found To Be Beneficial:

Mucous Removal Device:

This is a device used to clear mucous from the lungs. A friend of mine with COPD suggested this to me (it helped her tremendously).

It loosens the mucous so you can cough it up. It does not need a prescription, but I would still run it by my doctor.

It reminds me of the vibrations from singing when you are sick, and the mucous becoming irritating. It is helpful for me when my muscles are NOT weakened, but causes some difficulties for me personally when they are.

Neti Pot:

When my allergies flare, I use a Neti pot. It is a container that helps remove debris and mucous from the nasal cavity.

To me, this is uncomfortable and I always try to just lean forward in steamy shower first, but it is very effective when I need more assistance clearing my nasal cavity.

There is a saltwater solution to use. Several people swear by this product that I have spoken to.

I do find it helpful when my strength is up, but do question the risk for infection.

I like how this is an alternative to taking a medication for some people (because I have plenty of those on my list already).

Mindful Breathing:

Learning to be aware of my breathing was absolutely beneficial to minimizing my symptoms of shortness of breath.

Athletes use this in training. Growing up on a military base, I can remember running with cadence. This is the same concept.

I am obviously not out here running miles with my muscles, but I do incorporate this in my meditations as much as possible.


If you are ever struggling with a breathing issue, please seek care.

This is not something you should ever put off!

I hope these explanations were helpful and will be a good resource when attempting to understand the conversation you have previously had with your doctor, or the one you plan to have.

Remember to dress in loose fitting clothes and be comfortable when going to these tests.

Keep in mind that your normal may be different that someone else's normal.

Each breathing test has its own purpose.

If you have any helpful tips on these, please comment them below!

If you haven't already, check out the ADVOCATE page on the website for more resources!

Disclaimer: This is not medical advice. If you are experiencing a medical emergency, please seek the appropriate care. Links in this article are affiliate links. For more information please see the terms and conditions.

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