The test ends after maintaining your target heart rate long enough to capture readings about heart function, usually about 10 to 15 minutes. Your target heart rate is higher than when at rest and based on your age and fitness level. Technicians may end the test early if you experience severe symptoms or ask to stop.
During your cardiac exercise stress test, you'll walk on a treadmill or cycle on an exercise bike until you reach your “target heart rate”- which is 85% of the maximum heart rate predicted for your age. Every 3 minutes, the speed, incline and resistance of your treadmill or bike will increase, up to 15 minutes maximum.
“Generally a test should last 8 to 12 minutes, unless it is prematurely stopped due to fatigue or abnormal signs/symptoms. Patients who remain on the treadmill for 7 minutes or longer are in good to excellent physical condition.”
Patients are categorized as low-, intermediate- or high-risk. Low risk (score > 5) indicates a 5-year survival of 97%. Intermediate risk (score between 4 and -11) indicates 5-year survival of 90%. High risk (score < -11) indicates 5-year survival of 65%.
The FAA does accept a minimum of 85% of maximum predicted rate, but stay on the treadmill as long as possible, up to nine minutes to demonstrate maximum effort. "The FAA allows for applicants over age 70 to exercise for at least six minutes, but must still attain 85% of predicted maximum heart rate."
A cardiac stress test can reveal blockages in your arteries through the various types of information it collects. If your blood oxygen level is below normal, the test reveals that your blood flow is partially blocked.
Normal systolic and diastolic responses to exercise stress testing should not exceed 220 and 100 mm Hg, respectively. Systolic blood pressure of >230 mm Hg is generally considered hazardous.
Stress test results
An exercise stress test is designed to find out if one or more of the coronary arteries feeding the heart contain fatty deposits (plaques) that block a blood vessel 70% or more. Additional testing is often required to confirm the test result.
The goal is to have your heart work hard for about eight to 12 minutes to thoroughly monitor its function. You continue exercising until you develop symptoms that do not allow you to continue. Occasionally your doctor may stop the test sooner for other reasons.
In the most widely used test, called the Bruce protocol, there are seven stages, each one lasting for three minutes. If you get to the last stage, you'll be walking at 5.5 mph up a 20% grade. The goal is to get your heart working up to at least 85% of its maximum capacity.
A chemical stress test for elderly people is important as it can help diagnose problems like heart disease, coronary artery disease, heart valve disease, and arrhythmias.
Exercise. Lastly, consider exercising before your stress test. A daily gym routine is not required. You should be able to achieve target heart rate during the stress test.
Interpreting the results of a stress test
Normal results from a stress test mean the patient has less than 70% artery blockage. Further testing might be recommended if the patient has risk factors for CAD. An abnormal result means the patient has more than 70% blockage in their coronary artery.
The sensitivity of exercise stress testing ranges from 23 to 100 percent, and the specificity ranges from 17 to 100 percent.
Minor symptoms of heart blockage include irregular or skipped heartbeats, shortness of breath and chest tightness. Other symptoms may include pain or numbness in the legs or arms, as well as neck or throat pain.
"When we exercise, the heart needs to pump more blood in each beat and in every minute, which causes systolic blood pressure to increase. The men who were measured with high blood pressure while exercising were in general achieving a higher workload -- they were more fit."
State and trait anxiety are more common in younger women compared to men, and high anxiety levels could affect hemodynamic reactivity during cardiac stress testing.
But what happens after you fail a stress test? Oftentimes, the next step for people who fail a stress test, and who have risk factors for or symptoms of cardiovascular disease, is an imaging test called a coronary angiography. Your doctor may call it a cardiac catheterization, or “cath” for short.
Do not smoke OR drink any caffeine (coffee, tea, decaf, chocolate, soda) for 24 hours before the test. For morning appointments, do not have anything to eat or drink after midnight. For morning appointments, please do not take your diabetic medication. Sips of water are okay.
Your throat is sprayed and will be numb. A mild sedative is given and you may sleep through this test. Your doctor will gently put a small, flexible, lubricated tube into your mouth and down your esophagus (swallowing pipe). You'll be able to breathe normally.
People usually can go back to normal activities immediately. You may want to drink plenty of fluids to help flush the tracer out of your body. After the test, you may feel tired or dizzy or have a headache. Those symptoms should go away with time and rest.