Exercise Stress Testing

Why do we need exercise stress tests?
Most patients experience difficulty breathing with exertion, e.g. carrying bundles, walking, climbing stairs, exercising. In order to determine the cause of the breathing problem, one needs to examine the patient while he/she is subjected to some form of physical stress.

What is involved in a stress test?
The patient exercises for a certain amount of time (3-15 minutes) on the bicycle or treadmill. The workload is gradually increased (speed and grade of the treadmill, or tension on the bicycle) depending on what the patient can tolerate. There are many types of stress tests. Cardiologists do stress tests primarily to determine if there is coronary artery disease. Often they will inject nuclear material to image the heart during and after exercise in addition to the usual evaluation of EKG and blood pressure. Pulmonary stress tests are concerned with the assessment of the combined cardiac and respiratory systems to the challenge of exercise to isolate the limiting factor to one is endurance. While the patient exercises during a pulmonary stress test, the following are monitored:

• EKG, heart rate
• Oxygen saturation
• Blood pressure
• Symptoms
• Respiratory pattern
• At the conclusion of the study the patient has spirometry to determine if there is exercise induced bronchospasm.

What will the stress test show?

• Differentiate cardiac from respiratory induced causes of chest pain or difficulty breathing.
• Establish limits of exercise endurance.
• Diagnose reactive airways and/or exercise induced bronchospasm.
• Determine any real disability as opposed to perceived difficulty with breathing.

Are stress tests safe?
Stress tests are generally safe and the patient should not be afraid to have a stress test because:

• The patient is monitored carefully.
• Patient safety and comfort are most important. At any time if there is the slightest problem, the study is terminated.
• The patient is screened before the study to determine the indications for the study and the goals.
• The speed or workload is adjusted to what the patient can practically tolerate.

Is it a good idea to have a stress test prior to embarking on an exercise program?
This is often suggested to certain high risk patients who suddenly decide to become healthy and start to exercise. It is far better to find out if there is some underlying respiratory or cardiac problem in the office under observation, then along the side of the road or in the middle of an athletic field. The physician can advise as to whether a cardiac or pulmonary stress test would be more appropriate in each case, depending on the particular patientís clinical history and needs. People who should seriously consider an exercise study include:

• Asthmatics who may precipitate an acute attack if not properly prepared.
• Sedentary middle aged people.
• Patients with chronic bronchitis and emphysema.
• Patients with a family history of respiratory or cardiac disease
• Patients with unexplained chest pain, chest tightness, or difficulty breathing.
• Patients with nocturnal difficulty breathing or chest pain.

Once the test is completed, what happens next?
The test needs to be scored and interpreted by the physician. Often we have the patient return one or two weeks later to review the results and make plans for any additional interventions. These may include:

• Adjustment of asthma or bronchitis medications.
• Prescribing oxygen for certain patients with chronic lung disease.
• Referral to a cardiologist for additional testing, possibly a stress thallium test to look at the coronary blood flow.
• Discussion of proper eating habits and caloric intake.
• Establishing exercise goals for pulmonary rehabilitation, or a personal exercise program.
  • Frequency and duration of exercise.
  • Optimal workload or type of exercise.
  • Target heart rate
  • Borg scale of work and breathing.

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© 2010 Tricia Lukowski