How to Measure Lung Capacity

Whether you have an existing respiratory condition, or have noticed difficulty or changes in your breathing, it is a good idea to take some tests to measure your lung capacity. Your lungs mature around your mid-20s, and as you grow older it is normal to experience changes in your breathing. However, it is important to monitor these changes in case they are a sign of something more serious. If you have an existing condition like asthma, there are home tests you can perform to monitor your condition and assist in your treatment. If you are experiencing new symptoms or have a very serious respiratory condition it is best to get checked at a doctor’s office by medical professionals.

Method 1 - Testing at Home with a Peak Flow Meter

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→ Ask your doctor if a home peak flow meter is right for you. If you have asthma or other respiratory problems, using a PFM at home can help you track your condition to prevent it from getting worse.

→ A peak flow meter is a handheld device that measures how well air moves out of your lungs when you blow into it forcefully.

→ If you only have mild asthma symptoms a PFM may not be necessary, but can very useful for more serious cases of asthma or if you have emphysema or chronic bronchitis.

→ Using a PFM will help you judge how well your treatment and medication are functioning.

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→ Buy a peak flow meter over-the-counter at a drugstore. There are several different types of these hand-held meters that are available over-the-counter, but they all work in a similar way. Your doctor will be able to recommend a meter that will work for you.

→ There are two ranges of peak flow meters available. Low-range meters are used only for small children, while mid-range meters are for older children to adults.

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→ Get your personal best reading by blowing into the PFM with no symptoms. Test yourself with the meter every day for 2-3 weeks and record your highest score each day. After 2-3 weeks, your highest number out of all the readings will be your personal best.

→ Good times to use your peak flow meter to get your personal best reading are between noon-2:00 p.m. and after you take any type of quick-relief medication you may be on.

→ If you are experiencing severe asthma symptoms right now and do not already have a personal best score from a PFM, you should call your doctor immediately.

→ Doctors can use your personal best reading to develop a treatment plan for your condition.

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→ Blow into the meter whenever your symptoms act up. If you don’t have symptoms you may not need to use the meter, but whenever you are having difficulties breathing you should take a reading and record the score. Provide this information to your doctor to help with your treatment.

→ If your peak flow reading is at 50-79 percent of your personal best your asthma is getting worse and you should use quick relief medication. If your reading is below 50 percent of your personal best, you are in your peak flow red zone and should take medicine and call your doctor right away.

→ Using a peak flow meter at home can also help you adjust your medication daily.

Method 2 - Getting Tested by a Doctor Using Spirometry

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→ Consult your doctor to determine if spirometry is necessary. Spirometry is the most common doctor’s office test used to diagnose respiratory diseases. Doctors also use the test to monitor the effectiveness of treatments for conditions such as asthma and other lung diseases.

→ Smokers or ex-smokers older than 40 should also use the test to screen for chronic obstructive pulmonary disease.

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→ Inform your doctor of any breathing medications you may be taking. Doctors may ask you to stop taking any medication you are on before a spirometry test to measure its effect on your breathing.

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→ Schedule an appointment with your doctor for the test. Most doctors will perform a spirometry test at least 3 times and take the highest score from the samples. The test may take from 30-90 minutes.

→ Spirometry tests are very simple to perform. A medical professional will instruct you to take the deepest breath you can and blow as hard into the spirometer machine as hard as possible for as long as possible. Other variations of breathing may be performed during the tests.

→ If you are already on medication such as an inhaler, the doctor may ask you to perform the test a second time after using your inhaler or medication to see how it affects your breathing.

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→ Avoid smoking, drinking alcohol, and strenuous exercise before the test. All of these activities cause stress to your lungs and should be avoided so as to not affect your test results. Ask your doctor for specific information about how long before your test these activities should be avoided.

→ You should also wear loose clothing that allows you to take deep breaths.

→ Avoid eating a large meal before the test as this can also restrict breathing.

Warnings

→ Always consult your doctor first before beginning any treatment or medication.

→ If you are experiencing a medical emergency call 911 immediately.