Submaximal Treadmill Walking Test

Submaximal treadmill walking tests are also called submaximal graded exercise tests or an exercise stress test. These tests check the limits of the cardiovascular system and your heart's capabilities. A submaximal test will end one of two ways. An ending point will be predetermined, but if you reach exertion before the preset end, the test will stop. A symptom-limited treadmill test will have no preset finish. The exercise intensity continues to increase until your cardiovascular system has reached its limit.

Who Should Have One

Submaximal treadmill walking tests are recommended for people who are already at risk for coronary irregularities and who might be looking to start an exercise program. According to "Fitness: The Complete Guide" by Frederick C. Hatfield, "Those 40 years of age or older with an abnormal physical examination (murmur, etc.) or two or more coronary risk factors, he/she should have a GXT before embarking on a vigorous exercise program."

Preparation

Before the test, taking your blood pressure, resting heart rate and an electrocardiogram is standard. This will check for cardiac issues while there is no stress on the cardiovascular system and provides a baseline for the test. The sensors placed on the chest for the ECG will remain throughout the test. Assessment of the blood pressure and heart rate is continuous as well. The results can indicate coronary problems and risk for cardiac diseases.

Administering the Test

Medical and fitness professionals should oversee treadmill stress tests, be knowledgeable of the equipment being used and capable of handling an emergency should one occur. According to the American Heart Association, "... exercise stress testing can be performed safely by properly trained nurses, exercise physiologists, physician assistants, physical therapists, or medical technicians working directly under the supervision of a physician, who should be in the immediate vicinity and available for emergencies."

Results

The results of the submaximal treadmill walking test can show indicators of coronary artery disease, though these results are not completely reliable. "Approximately 10 percent to 20 percent of GXT's result in false positives (i.e. the test erroneously indicates that an individual has heart disease)," according to "Fitness: The Complete Guide." Unfortunately, a higher proportion (20 percent to 40 percent) of false negative (i.e. the test incorrectly indicated that an individual is free of heart disease) GXT results occur."