Lung function tests, which are also referred to as pulmonary function tests, are used to check how well your lungs work. These tests are used for finding the cause of breathing problems and measuring the effectiveness of treatments for lung disease. Lung function tests are recommended for people who have breathing problems and do not know the cause. They are also recommended for people with a diagnosed respiratory disorder, such as asthma, chronic obstructive pulmonary disorder (COPD), or reactive airway disease. If you are trying a new medication for asthma or COPD, you may need lung function tests to see if the treatment has improved your breathing. Some individuals may be advised to take lung function tests as a preventive measure, such as people who work with chemicals or who might be exposed to fibers or pollutants that could cause lung diseases.
There are several types of lung tests, including exercise stress tests and inhalation tests. Before you have one of these tests, you should wear loose clothing, avoid smoking and avoid eating a heavy meal. Your doctor will let you know if you should take your medication before the tests. You should also avoid caffeinated drinks before the test. This is because caffeine relaxes your airways. Lung function tests require that you make a tight seal with your lips around a tube. The respiratory therapist or doctor will put a nose clip on you during the test in order to prevent any air from leaking out through your nostrils. You will take deep breaths through your mouth and exhale through your mouth. If you are having an exercise stress test, you may be instructed to walk or run on a treadmill for a certain amount of time and then breathe through the tube. You might be given an inhaled or sprayed medication during the testing. After lung function tests, you might feel tired. You should return to your usual daily activities.