What is Spirometry? Purpose, Procedure & Results

Spirometry is a simple breathing test that measures how much air you can breathe in and out, and how quickly you can do it. Think of it as a fitness test for your lungs - it helps doctors understand how well your respiratory system is working and whether there might be any issues affecting your breathing.

What is spirometry?

Spirometry is a painless lung function test that measures your breathing capacity and airflow. During the test, you'll breathe into a device called a spirometer, which records detailed information about your lung performance.

The test focuses on two main measurements: how much air your lungs can hold and how fast you can push that air out. These numbers help doctors spot breathing problems early and track how well treatments are working over time.

Most people find spirometry straightforward and comfortable. The entire process usually takes about 15-30 minutes, and you'll be able to go about your normal day immediately afterward.

Why is spirometry done?

Doctors recommend spirometry to diagnose breathing conditions, monitor existing lung problems, and check how well treatments are working. It's one of the most reliable ways to get a clear picture of your lung health.

If you've been experiencing symptoms like shortness of breath, persistent coughing, or chest tightness, spirometry can help identify the underlying cause. The test is particularly useful for detecting conditions like asthma, chronic obstructive pulmonary disease (COPD), and other respiratory disorders.

Your doctor might also order spirometry as part of a routine health checkup, especially if you have risk factors for lung disease. These could include a history of smoking, exposure to workplace chemicals, or a family history of respiratory conditions.

Sometimes spirometry is done before surgery to make sure your lungs are healthy enough for anesthesia. It's also helpful for monitoring how well medications are controlling conditions like asthma or COPD.

What is the procedure for spirometry?

The spirometry procedure is straightforward and takes place in your doctor's office or a specialized testing facility. You'll sit comfortably in a chair while a trained technician guides you through the entire process.

First, the technician will place a soft clip on your nose to make sure all the air goes through your mouth during the test. Then you'll place your lips around a sterile mouthpiece that's connected to the spirometer machine.

Here's what happens during the actual breathing tests:

1. You'll take the deepest breath possible, filling your lungs completely
2. Then you'll blow out as hard and fast as you can for as long as possible
3. The technician will coach you through each breath, giving clear instructions
4. You'll repeat this process several times to ensure accurate results
5. Sometimes you'll also do slow, steady breathing tests for additional measurements

The technician will encourage you throughout the test and may ask you to try a few times to get your best effort. Don't worry if you feel a bit lightheaded - this is normal and will pass quickly.

In some cases, your doctor might want to see how your lungs respond to medication. If so, you'll use an inhaler and then repeat the spirometry test about 15 minutes later to compare the results.

How to prepare for your spirometry test?

Preparing for spirometry is simple, but following a few guidelines will help ensure the most accurate results. Your doctor's office will give you specific instructions, but here are the general preparation steps.

On the day of your test, wear loose, comfortable clothing that won't restrict your breathing. Avoid tight belts, restrictive shirts, or anything that might make it harder to take deep breaths.

Your doctor may ask you to temporarily stop certain medications before the test. These preparations help ensure your results reflect your lungs' natural function:

• Avoid using rescue inhalers for 4-6 hours before the test
• Don't use long-acting bronchodilators for 12-24 hours beforehand
• Skip caffeine and avoid smoking for at least 4 hours prior
• Eat only a light meal before your appointment
• Continue taking your regular medications unless specifically told otherwise

Make sure to tell your healthcare provider about all medications and supplements you're taking. They'll help you create a safe plan for your specific situation.

Try to arrive at your appointment feeling relaxed and well-rested. If you have a cold, fever, or respiratory infection, it's better to reschedule the test for when you're feeling completely well.

How to read your spirometry results?

Understanding your spirometry results becomes easier when you know what the key numbers mean. Your doctor will explain your specific results, but here's what the main measurements tell us about your lung function.

The two most important measurements are FEV1 and FVC. FEV1 stands for "Forced Expiratory Volume in 1 second" - this measures how much air you can blow out in the first second of your hardest breath.

FVC means "Forced Vital Capacity" and represents the total amount of air you can exhale after taking your deepest possible breath. Think of FVC as the size of your lung's air tank, while FEV1 shows how quickly you can empty it.

Your results are compared to predicted normal values based on your age, height, sex, and ethnicity. Here's how doctors typically interpret the percentages:

• 80% or higher of predicted values: Normal lung function
• 70-79% of predicted values: Mild reduction in lung function
• 60-69% of predicted values: Moderate reduction
• 50-59% of predicted values: Moderately severe reduction
• Below 50% of predicted values: Severe reduction in lung function

The ratio between FEV1 and FVC is also important. A normal ratio is usually 0.75 or higher, meaning you can blow out at least 75% of your total lung capacity in the first second.

Your doctor will look at all these numbers together, along with your symptoms and medical history, to get a complete picture of your lung health. Remember that one test is just a snapshot - your doctor might recommend repeat testing to track changes over time.

How to improve your spirometry results?

While you can't change your natural lung capacity, there are several ways to optimize your lung function and potentially improve your spirometry results over time. The key is focusing on overall respiratory health and following your doctor's treatment plan.

If you smoke, quitting is the single most important step you can take for your lung health. Even if you've been smoking for years, your lungs begin to heal and function better within weeks of stopping.

Regular exercise can significantly improve your lung function and breathing efficiency. These activities can be particularly beneficial for your respiratory health:

• Walking, swimming, or cycling for cardiovascular fitness
• Breathing exercises and techniques like diaphragmatic breathing
• Yoga or tai chi for breath control and relaxation
• Singing or playing wind instruments to strengthen respiratory muscles
• Pulmonary rehabilitation programs if recommended by your doctor

Taking your prescribed medications exactly as directed is crucial for managing conditions like asthma or COPD. Don't skip doses or stop medications without talking to your healthcare provider first.

Avoiding respiratory irritants can also help protect your lung function. This includes staying away from secondhand smoke, strong chemical fumes, and air pollution when possible.

If you have allergies, managing them effectively can reduce inflammation in your airways and improve your breathing. Your doctor might recommend allergy medications or suggest ways to avoid your specific triggers.

What are the risk factors for abnormal spirometry results?

Several factors can increase your likelihood of having abnormal spirometry results, and understanding these can help you take steps to protect your lung health. Some risk factors you can control, while others are part of your natural makeup.

Smoking is by far the biggest controllable risk factor for poor lung function. This includes cigarettes, cigars, pipes, and even secondhand smoke exposure over many years.

Environmental and occupational exposures can also significantly impact your lung health over time. These risk factors deserve special attention:

• Long-term exposure to dust, chemicals, or fumes at work
• Living in areas with high air pollution levels
• Exposure to asbestos, silica, or other harmful particles
• Indoor air pollution from wood-burning stoves or poor ventilation
• Frequent respiratory infections during childhood

Some risk factors are beyond your control but still important to be aware of. A family history of lung diseases like asthma, COPD, or pulmonary fibrosis can increase your risk.

Age naturally affects lung function - after about age 25, lung capacity gradually decreases by small amounts each year. This is completely normal, but conditions like COPD can accelerate this decline.

Certain medical conditions can also affect your spirometry results. These include heart disease, chest wall deformities, neuromuscular disorders, and previous lung infections or injuries.

What are the possible complications of low spirometry results?

Low spirometry results often indicate underlying lung conditions that, if left untreated, can lead to various complications. Understanding these potential issues can help motivate you to work closely with your healthcare team on treatment and management.

Reduced lung function can make everyday activities more challenging over time. You might find yourself getting short of breath more easily when climbing stairs, walking long distances, or even during normal daily tasks.

When lung function is significantly impaired, your body may not get enough oxygen during physical activity or even at rest. This can lead to several concerning complications:

• Increased risk of respiratory infections like pneumonia
• Heart strain from working harder to pump blood through damaged lungs
• Reduced exercise tolerance and physical fitness
• Sleep disturbances due to breathing difficulties
• Anxiety or depression related to breathing limitations

In severe cases, low lung function can progress to respiratory failure, where the lungs can't provide enough oxygen or remove enough carbon dioxide from the blood. This is a serious condition that requires immediate medical attention.

Some people with significantly reduced lung function may eventually need supplemental oxygen therapy to maintain adequate oxygen levels in their blood. While this might sound scary, oxygen therapy can actually help you feel more energetic and comfortable.

The good news is that with proper treatment and management, many of these complications can be prevented or significantly delayed. Early detection through spirometry testing allows for timely intervention and better long-term outcomes.

When should I see a doctor for spirometry?

You should consider asking your doctor about spirometry if you're experiencing persistent breathing symptoms or have risk factors for lung disease. Early testing can catch problems before they become more serious.

If you're having trouble breathing, it's important not to ignore these symptoms. Persistent shortness of breath, especially during activities you used to do easily, warrants evaluation with spirometry.

These symptoms suggest it might be time to discuss spirometry testing with your healthcare provider:

• Chronic cough that lasts more than a few weeks
• Shortness of breath during normal activities
• Wheezing or whistling sounds when you breathe
• Chest tightness or feeling like you can't get enough air
• Frequent respiratory infections
• Fatigue that might be related to breathing problems

Even if you don't have symptoms, your doctor might recommend spirometry if you have significant risk factors. This is especially true if you're a current or former smoker, work in an environment with lung irritants, or have a family history of lung disease.

If you've already been diagnosed with a lung condition like asthma or COPD, regular spirometry testing helps your doctor monitor your condition and adjust treatments as needed. Don't wait for symptoms to worsen - preventive monitoring is key.

Trust your instincts about your breathing. If something feels different or concerning, it's always better to have it checked out. Your doctor can help determine if spirometry is right for your situation.