In most cases, enough information can be obtained from lung function tests done while setting at rest. It is occasionally important to measure lung and heart function under the stress of exercise because some problems only show up during exercise. Exercise is usually performed on a bicycle or a treadmill. During the test the pedal pressure or the treadmill speed are increased. Measurements are made including the amount of oxygen used, carbon dioxide produced by the body, the total amount of air breathed in and out, together with the heart and breathing rate.
Breathing is measured through a mouthpiece.
Most people are able to pedal for 10 to 15 minutes whilst others can last for half an hour. There is a wide range of values for different people. Another type of exercise test is the 12-minute walk test. It is a very simple procedure where measurements are made of how far you can walk in 12-minute periods. When you have an exercise test, be sure to bring comfortable clothing suitable for exercising, such as a tracksuit, and avoid having a heavy meal for 2-3 hours beforehand.