Exercising with Angina and Silent Ischemia
The heart requires an uninterrupted, stable supply of oxygen to survive, since oxygen is virtually its only fuel. During our daily activities and exercise, the demand for myocardial oxygen varies. The heart adjusts the coronary blood flow to meet the changing demand for oxygen. However when there is an obstruction in the coronary arteries, due to atherosclerosis, myocardial ischemia, or restriction in the blood flow, develops. When this condition causes pain in the chest, it is called angina.
Stable angina is usually associated with crossing the threshold of a certain level of physical exertion, or other stresses, such as emotional distress or cold temperatures. And is usually treated with rest and/or nitroglycerin.
Unstable angina is much riskier to deal with than the stable variety. There are three main hallmarks of UA:
- Angina experienced while at rest, or upon wakening, which lasts 20 minutes or more
- The first occurrence of anginal pain
- Increase in severity, frequency, length or change in the level of activity that brings on the pain, with already documented angina
UA is often a warning sign of myocardial infarction – “heart attack”, and should be treated immediately with appropriate medical intervention. The severity of the coronary artery obstruction largely determines how much exercise a person can tolerate.
Exercise is generally helpful for people with stable angina. Exercise and changes in lifestyle choice, such as an improved diet, will help reduce cardiac risk. The goal of exercise and angina sufferers is to raise their ischemic threshold, or the point during exercise at which the symptoms of angina occur. Proper medication will also help exercise performance. Most people with stable angina who exercise will realize most, if not all, of the same benefits as seemingly healthy people. These benefits include improvements in blood pressure and heart rate, and better flow of oxygenated blood to the heart both at rest and during exertion.
Before starting on an exercise program, the person needs to determine the ischemic threshold, or the heart rate above which the symptoms of angina appear. The recommendations for exercise include:
- Aerobic: large muscle activities, such as walking briskly. Increase daily activities such as gardening, housework, errands, etc. Aerobic work should be done 3-7 days per week, around 20-60 minutes per session, with 5-10 minutes of a warm-up and also a cool-down. It’s important to keep the heart rate 10-15 contractions/ minute below the ischemic threshold.
- Circuit training is recommended for strength, to improve functional capacity. Do this 2-3 days/week, for 15-20 minutes per session, and your effort should be light resistance.
- Flexibility: stretching. Do upper and lower Range of Motion (ROM) activities, 2-3 days per week. This will improve your flexibility and reduce the chance of injury during exercise and activities of daily life.