Patients with coronary artery blockages may have minimal symptoms and an unremarkable or unchanged EKG while at rest. However, symptoms and signs of heart disease may become unmasked by exposing the heart to the stress of exercise. During exercise(heavy or light physical exertions) , healthy coronary arteries dilate (develop a more open channel) than an artery that has a blockage. This unequal dilation causes more blood to be delivered to heart muscle supplied by the normal artery. In contrast, narrowed arteries end up supplying reduced flow to it's area of distribution. This reduced flow causes the involved muscle to "starve" during exercise. The "starvation" may produce symptoms (like chest discomfort or inappropriate shortness of breath), and the EKG may produce characteristic abnormalities. Most commonly, a motorized treadmill is used for exercise, while a stationary bicycle is used in some exercise laboratories. When is a Regular Stress Test ordered? A regular stress test is considered in the following circumstances:

Patients with symptoms or signs that are suggestive of coronary artery diseases (CAD). Patients with significant risk factors for CAD.

To evaluate exercise tolerance when patients have unexplained fatigue and shortness of breath.

To evaluate blood pressure response to exercise in patients with borderline hypertension.

To look for exercise-induced serious irregular heart beats. Please remember that the regular stress test is heavily dependent upon interpretation of EKG changes produced by exercise.

The patient is brought to the exercise laboratory where the heart rate and blood pressure are recorded at rest. Sticky electrodes are attached to the chest, shoulders and hips and connected to the EKG portion of the Stress test machine. A 12-lead EKG is recorded on paper. Each lead of the EKG represents a different portion of the heart, with adjacent leads representing a single wall. For example:

Leads 2, 3, and aVF = bottom or inferior portion of the heart.

Leads V1 and V2 = septum or partition of the heart.

Leads V3, V4, V5 and V6 = anterior or front portion of the heart. Leads 1 and aVL = superior or top and outer left portion of the heart.

Lead aVR looks at the cavity of the heart and has almost no clinical value in identifying coronary disease.

Three of the EKG leads are also constantly displayed on the treadmill monitor. Each lead representing a different wall. The physician has the option of selecting different combinations of three.

The treadmill is then started at a relatively slow "warm-up" speed. The treadmill speed and it's slope or inclination are increased every three minutes according to a preprogrammed protocol (Bruce is the commonest protocol in the USA, but several other protocols are perfectly acceptable). The protocol dictates the precise speed and slope. Each three minute interval is known as a Stage (Stage 1, Stage 2, Stage 3, etc. Thus a patient completing Stage 3 has exercised for 3 x 3 = 9 minutes). The patient's blood pressure is usually recorded during the second minute of each Stage. However, it may be recorded more frequently if the readings are too high or too low. As noted earlier, the EKG is constantly displayed on the monitor. It is also recorded on paper at one minute intervals. The physician pays particular attention to the heart rate, blood pressure, changes in the EKG pattern, irregular heart rhythm, and the patient's appearance and symptoms. The treadmill is stopped when the patient achieves a target heart rate (this is 85% of the maximal heart rate predicted for the patient's age).

However, if the patient is doing extremely well at peak exercise, the treadmill test may be continued further. The test may be stopped prior to achievement of the target heart rate if the patient develops significant chest discomfort, shortness of breath, dizziness, unsteady gait, etc., or if the EKG shows alarming changes or serious irregular heart beats. It may also be stopped if the blood pressure (BP) rises or falls beyond acceptable limits. Please note that the systolic BP (upper number) may normally rise to 200 at peak exercise. At the same time, the diastolic BP (lower number) remains unchanged or falls to a slight degree. In contrast, the BP of patients with hypertension or high BP will show a rise of both systolic and diastolic readings. The latter may rise above 90 - 100.

Preparing for the Regular Stress Test:

The following recommendations are "generic" for all types of cardiac stress tests: Do not eat or drink for three hours prior to the procedure. This reduces the likelihood of nausea that may accompany strenuous exercise after a heavy meal. Diabetics, particularly those who use insulin, will need special instructions from the physician's office. Specific heart medicines may need to be stopped one or two days prior to the test. Such instructions are generally provided when the test is scheduled. Wear comfortable clothing and shoes that are suitable for exercise. An explanation of the test is provided and the patient is asked to sign a consent form. How long does the entire test take? A patient should allow approximately one hour for the entire test, including the preparation.

This is a type of nuclear scanning test or myocardial perfusion (mi"o-KAR'de-al per-FU'zhun) imaging test. It shows how well blood flows to the heart muscle. It's usually done along with an exercise stress test on a treadmill or bicycle.

The thallium stress test is useful to determine:

- Extent of a coronary artery blockage

- Prognosis of patients who've suffered a heart attack

- Effectiveness of cardiac procedures done to improve circulation in coronary arteries

- Cause(s) of chest pain

- Level of exercise that a patient can safely perform

- If the test is normal during both exercise and rest, then blood flow through the coronary arteries is normal. The coronary arteries supply blood to the heart muscle.

- If the test shows that perfusion (blood flow) is normal during rest but not during exercise (a perfusion defect), then the heart isn't getting enough blood when it must work harder than normal. This may be due to a blockage in one or more coronary arteries.

- If the test is abnormal during both exercise and rest, there's limited blood flow to that part of the heart at all times.

- If no thallium is seen in some part of the heart muscle, the cells in this part of the heart are dead from a prior heart attack. (They have become scar tissue.)

The first pictures are made shortly after the exercise test and show blood flow to the heart during exercise. The heart is "stressed" during the exercise test -- thus the name "stress test." The patient then lies quietly for 2-3 hours and another series of pictures is made. These show blood flow to the heart muscle during rest.

Sometimes you can't do an exercise test because you're too sick or have physical problems. In this case, a drug such as dipyridamole (di-pi-RID'ah-mol) or adenosine is given. This drug increases blood flow to the heart and thus "mimics" an exercise test. Then the thallium test is given.

Most people can raise their HDL (good cholesterol) levels by exercising, not smoking and staying at a healthy weight.

No matter what the reason, successful weight loss and healthy weight management depend on sensible goals and expectations. If you set sensible goals for yourself, chances are you'll be more likely to meet them and have a better chance of keeping the weight off. In fact, losing even five to 10 percent of your weight is the kind of goal that can help improve your health.

Most overweight people should lose weight gradually. For safe and healthy weight loss, try not to exceed a rate of two pounds per week. Sometimes, people with serious health problems associated with obesity may have legitimate reasons for losing weight rapidly. If so, a physician's supervision is required.

Fad diets that maybe ignore the principles of the Dietary Guidelines may result in short term weight loss, but may do so at the risk of your health. How you go about managing your weight has a lot to do with your long-term success. Unless your health is seriously at risk due to complications from being overweight or obese, gradual weight loss should be your rule — and your goal.

• Check with your doctor (or physician/medical professional) . Make sure that your health status allows lowering your caloric intake and increasing your physical activity.
• Follow a calorie-reduced, but balanced diet that provides for as little as one or two pounds of weight loss a week. Be sure to include at least five servings a day of fruits and vegetables, along with whole grains, lean meat and low fat dairy products. It may not produce headlines, but it can reduce waistlines. It's not "miracle" science — just common sense. Most important, it's prudent and healthy.
• Make time in your day for some form of physical activity. Start by taking the stairs at work, walking up or down an escalator, parking at the far end of a lot instead of cruising around for the closest spot. Then, assuming your physician gives the okay, gradually add some form of regular physical activity that you enjoy. Walking is an excellent form of physical activity that almost everyone can do.
• Consider the benefits of moderate weight loss. There's scientific evidence that like losing five to 10 percent of your weight and keeping it off can benefit your health — lower your blood pressure, for example. If you are 5 feet 6 inches tall and weigh 180 pounds, and your goal weight is 150, losing five to 10 percent (nine to 18 pounds) is beneficial. When it comes to successful weight loss and weight management, steady and slow can be the way to go.

• how much and what kinds of food you eat
• whether your lifestyle includes regular physical activity
• whether you use food to respond to stress and other situations in your life
• your physiologic and genetic make-up
• your age and health status.

Successful weight loss and weight management should address all of these factors. And that's the reason to ignore products and programs that promise quick and easy results, or that promise permanent results without permanent changes in your lifestyle. Any ad that says you can lose weight without lowering the calories you take in and/or increasing your physical activity is selling fantasy and false hope. In fact, some people would call it fraud. Furthermore, the use of some products may not be safe.

Several other factors, including your medical history, can increase your health risk.

See your doctor for advice about your overall health risk and the weight loss options that are best for you. Together, decide whether you should go on a moderate diet (1200 calories daily for women, 1400 calories daily for men), or whether other options might be appropriate.

Once you and your doctor have determined the type of diet that makes the most sense for you, you may want to choose a product or a plan to help you reach your goal. Consider: b If your doctor prescribes a medication, ask about complications or side effects, and tell the doctor what other medications, including over-the-counter drug products, and dietary supplements you take and other conditions you're being treated for. After you start taking the medication, tell the doctor about changes you experience, if any.