About exercise tests
There are different types of exercise tests that may be performed, depending on the questions that need to be answered. Exercise tests usually are performed on a stationary bicycle or a treadmill. The equipment is selected and adjusted to meet the individual needs of each patient. During the exercise test, the resistance pedaling or the speed and elevation of the treadmill are gradually increased until the patient can no longer comfortably keep up with the machine. Patients usually exercise for about 10-15 minutes, and are monitored for about 10 minutes before and after exercise.
Components of an exercise test:
- EKG monitoring —All subjects are hooked up to a special exercise-EKG, system to monitor the heart rhythm during exercise and to assess other exercise-related EKG abnormalities that may indicate the presence of a heart problem.
- Metabolic measurements —By having the patient breathe through a snorkel-like mouthpiece that is connected to a special computer, the air that a patient breathes in and out during exercise can be measured, and a great deal of information can be gathered about response of the heart and lungs to exercise.
- Blood pressure measurements —Blood pressure cuffs are used to monitor a patient's blood pressure before, during and after exercise.
- Pulse oximetry —A pulse oximeter may be attached to a patient's finger to non-invasively measure his/her oxygen saturation before, during and after exercise.
- Spirometry —Simple measurements of a patient's lung function may be performed before and/or after exercise. These measurements are performed simply by having the subject blow through a special mouthpiece that is connected to a computer. The results are used to identify lung problems that might affect a patient's ability to exercise and to see whether exercise has an adverse effect on a patient's lung function, which may occur in patients with conditions such as exercise induced asthma.
- Echocardiographic measurements —Sometimes it is helpful to perform echocardiographic measurements during, or immediately after, exercise to further assess the effect of exercise on a patient's cardiovascular system.Myocardial perfusion imaging —Patients who are suspected to have, or are at increased risk for, coronary artery problems may have a special dye injected through an IV before and after exercise. Pictures of the heart may then be obtained to help determine whether the blood flow to any part of the heart is impaired at rest and/or during exercise
Questions addressed during an exercise test:
What causes a patient to stop exercising?
- A cardiovascular problem
- A pulmonary problem
- Being "out of shape" or overweight
- A neuromuscular problem
- An orthopedic problem
- Emotional issues
- Metabolic, hematologic or other medical problems
- How does the patient's exercise capacity compare to others of the same age and size?
- How does the patient's current status compare to one or more years ago?
- What might improve his/her status?
- How might the effectiveness of these interventions be assessed?
- Does exercise pose any risks for the patient?
- Can anything be done to minimize those risks?
- Can the effectiveness of the risk lowering strategies be assessed?
- If the patient is having symptoms during exercise, what might the cause of the symptoms be?
- What is the patient's prognosis?