Exercise for cardiovascular disease: prevention and underlying physiology
Cardiovascular disease (CVD) is the world’s leading cause of mortality. An estimated 17.5 million people died from CVD in 2012, representing 31% of all global deaths. Of these deaths, an estimated 7.4 million were due to coronary heart disease and 6.7 million were due to stroke (WHO, 2015).
CVD is an umbrella term covering a number of diseases that affect the heart and blood vessels. These include:
- Coronary heart disease: This is a disease of the blood vessels which supply the heart that greatly increases the risk of heart attack.
- Peripheral arterial disease: This is a disease of the blood vessels that supply the limbs.
- Cerebrovascular disease: This is a disease of the blood vessels supplying the brain that can result in a stroke.
- Hypertension, or chronically elevated blood pressure: This is a major risk factor for development of all of the conditions mentioned above.
Along with genetic risk factors, diet, tobacco and alcohol consumption, physical inactivity is a major risk factor for development of CVD and hypertension.
Exercise and CVD
The evidence that physically active people have decreased incidence of heart attacks when compared with sedentary peers has been known for over 50 years. In that time, the physiological mechanisms underlying exercise-induced protection against CVD have been comprehensively investigated.
It has been discovered that exercise:
- Reduces blood pressure in hypertensive patients
- Decreases plasma triglyceride (fat) levels
- Raises plasma HDL-cholesterol (so-called “good” cholesterol)
- Decreases plasma LDL-cholesterol (so-called “bad” cholesterol)
- Protects against atherosclerosis (hardening of the arteries).
We saw in Week 1 of this course how the heart responds to both acute and chronic exercise. Regularly increasing heart rate via exercise helps to maintain the efficiency of the heart muscle and maintain its health through the lifespan.
Regular exercise also helps to prevent arterial stiffness, maintaining blood vessel health and aiding delivery of blood to all tissues, including the heart muscle, skeletal muscle and the brain. These benefits maintain and, depending on effort, improve aerobic capacity or fitness, resulting in better quality of life throughout life and decreased risk of preventable disease.
Prevention of CVD
Everyone should make efforts to follow the fundamental physical activity guidelines for health (30 minutes moderate activity on at least 5 days per week) as we have discussed in Step 1.16. This alone can reduce the risk of coronary heart disease by approximately 30%.
When it comes to cardiovascular health, any exercise is better than none, and in healthy people, the more exercise you engage in, the better.
In the next step, we go into more detail into how exercise can be prescribed for those with CVD.
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