Patient’s oxygen levels are obviously very important. Pulse oximetry is routinely done in our office to help measure patient’s oxygen levels. This gives us a good idea of not only how severe a patient’s disease is, but also if a patient is sick, how sick they really are. Generally pulse oximetry is done at rest, but being pulmonary specialists, we also worry about how the lungs are functioning during activity. We are able to measure a patient’s oxygen levels while the patient is exerting by a test called a 6 minute walk. Generally the patient will walk on a treadmill while the oxygen levels are measured in real time. This enables us to determine whether or not a patient may need oxygen when walking or performing everyday activities.