Written by Michael Shipe, M.S., RCEP
What is coronary heart disease?
The American Heart Association (AHA) reports that 16 million adult Americans have been diagnosed with coronary heart disease (CHD), and it is responsible for 500,000 fatalities annually. CHD is characterized by a significant build-up of plaque (comprised of cholesterol and calcium deposits) in the coronary arteries of the heart. Coronary arteries provide the blood and oxygen supply to the heart, and blockage of these arteries via plaque build-up reduces the delivery of both. Although regular aerobic exercise requires the heart to work harder, a remarkable amount of scientific evidence indicates that an appropriate amount of exercise is a viable means to effectively manage the primary risk factors associated with CHD. Individuals with CHD who observe some simple precautions can exercise independently in a safe manner.
Safety of moderate-intensity exercise
Individuals who have been diagnosed with CHD are recommended by the American Heart Association (AHA) and the American College of Sports Medicine (ACSM) to obtain their physician’s consent before exercising on their own. Understandably, the prospect of exercising in an unsupervised capacity may be unnerving for someone who has previously suffered a heart attack. Yet research regarding individuals with CHD who exercise appropriately indicates there is only one heart attack and one death for every 294,000 and 784,000 hours of exercise, respectively. Although the risks of exercise are minimal, the benefits are substantial.
How exercise helps:
Primary and secondary risk factors
Primary risk factors increase the chances of developing CHD. They are commonly classified as either modifiable (e.g., smoking, high blood pressure, etc.) or non-modifiable (e.g., having immediate relatives with CHD). Regular physical inactivity has a positive impact on every modifiable risk factor for CHD, such as:
- High blood pressure: Regular aerobic activities can lower systolic and diastolic blood pressure 5-10 mmHg, which translates into a 10- to 20-percent reduction in heart attack risk.
- Cigarette smoking: Smokers who become physically active are more likely to stop smoking or at least reduce the amount they smoke.
- Diabetes: Regular aerobic activity has a profound effect on improving resting blood sugar levels and reducing the complications associated with diabetes.
- High cholesterol: Individuals who perform regular aerobic activity lower their bad cholesterol (e.g., LDL cholesterol) levels while simultaneously significantly increasing their good cholesterol (e.g., HDL cholesterol) levels.
- Obesity: Although regular aerobic physical is associated with moderate weight loss (e.g., a reduction of approximately 5 percent in body weight), this amount of weight loss is associated with positive changes in blood pressure, cholesterol and blood sugar.
The appropriate amount of exercise required to positively impact the risk factors can be readily demonstrated by the FIT principle: the frequency, intensity and time individuals with CHD are recommended to exercise.
Physical activity recommendations
AHA and ACSM recommend the accumulation of a minimum of 30 to 60 minutes of moderate physical activity four to five times per week, coupled with an increase in daily lifestyle activities, in order to prevent heart attack and death among patients with CHD. It is important to note that exercise can be accumulated in 10- or 15-minute bouts. Thus, individuals can perform three 10-minute or two 15-minute bouts on the days they exercise. In addition, exercise does not have to be vigorous in order to be beneficial regarding its ability to effectively manage CHD. Moderate-intensity exercise examples include brisk walking and light cycling. One manner in which to determine if a given activity is moderate or vigorous intensity is the talk test. If an individual can maintain a conversation while they are talking, they are likely exercising at a moderate intensity; if they cannot, they may be exercising vigorously.
Exercise guidelines for individuals with CHD
In addition to following the FIT principle recommendations, individuals with CHD should take the following precautions to ensure the safety of exercise and to reduce the chances of experiencing heart complications while exercising:
- Contact their primary physician to obtain approval before exercising independently.
- Always perform a proper warm-up and cool-down activity, such as walking slowly (e.g., two miles per hour) five to seven minutes before and after you exercise.
- Never exercise to the point of chest pain or angina. If chest pain occurs during exercise, call 911 immediately.
- Exercise with a friend and/or always carry a cell phone to ensure emergency personnel can be contacted quickly if necessary.
- If prescribed, always carry nitroglycerin, especially when exercising.
- Exercise should be stopped immediately if dizziness, nausea, unusual shortness of breath or irregular heart beats occur during or immediately after exercise. A physician should be contacted immediately, although you may simply need to slow down a bit.
- Do not exercise outdoors when it is too cold, hot, or humid, as this weather may increase the likelihood of the aforementioned conditions.
Individuals who perform the recommended frequency, intensity and duration of exercise will likely experience minimal heart-related risks while reaping the benefits of a positive impact on their primary risk factors for CHD. These changes lead to a significant reduction in future heart attacks and fatalities associated with CHD.
View the full summer 2008 issue of the ACSM Fit Society® Page online.