There is not a standard normal result for stress tests, as there are multiple types, and results are based on many factors including age, reason for the test and medical history, explains MedlinePlus. Some types of stress tests include nuclear, treadmill, dobutamine and echocardiogram testing, notes WebMD.
Generally an exercise stress test is done until a person reaches a target heart rate, a change in ECG suggests the heart is not getting adequate oxygen, chest pain occurs, or a concerning change in blood pressure develops, states MedlinePlus.
People who cannot exercise are given a drug that causes the heart to react as if exercise is taking place, according to WebMD. A nuclear stress test involves a radioactive material being injected into the patient, which produces clear pictures of heart tissue.