Why is exercise important for heart health?

Physical activity is good for the heart.
Physical activity lowers blood pressure and triglyceride levels. See more heart health pictures.
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At any given time, 13 million Americans are suffering from coronary artery disease­ (CAD), the most common cause of heart attacks [source: WebMD]. In people with CAD, a combination of high cholesterol levels and other fats in the blood collects on the inner lining of the heart's arteries, eventually forming a thick plaque that attracts clotting agents in the blood. Once a clot forms, it's very difficult for blood to get to the heart. That's when a heart attack occurs -- cells in the oxygen-depleted heart start to die, and the heart falters.

For some people, heart disease is out of their control, a result of genetics or diabetes; but more often than not, it could have been prevented. Even after coronary artery disease has taken hold, preventive measures can still curtail its progression to heart attack or debilitating illness. Some of the best preventive measures include eating a low-fat, high-fiber diet and getting regular exercise.


It's obvious why eating less fat would decrease the chances of developing clogged arteries. At its simplest, if there's less fat in the body, there's less fat available to build up on artery walls. The heart-healthy effects of exercise are perhaps less intuitive, but they're just as pronounced. Physical activity has a tremendous effect on the heart: Research has shown that overweight people who exercise have a lower risk of heart disease than thin people who don't [source: Health]. Thirty minutes of moderate-to-high exertion activities -- such as running or playing basketball -- at least three times a week can decrease your risk of developing heart disease by at least 20 percent [source: WebMD].

In this article, we'll look at the effects exercise have on the heart and how that relates to the risk for heart disease. The connection is more direct than you may think.


Health Effects of Exercise

Aerobic exercise lowers your risk of getting heart disease.
Aerobic exercise lowers your risk of getting heart disease.
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Physical activity is crucial to general health. It helps people maintain a healthy weight and reduces stress levels; people who exercise regularly are less likely to smoke cigarettes or overeat. But more than that, exercise directly targets primary aspects of heart health: cholesterol, triglycerides and blood pressure.

The form of exercise most often connected with decreasing heart disease is aerobic exercise. That's exercise that raises your heart rate, like jogging, swimming, jumping rope or bike riding. Aerobic exercise can decrease the risk of heart disease by 20 to 60 percent, depending on the exertion level, duration and frequency [source: Health].


Part of the benefit has to do with the fact that aerobic exercise lowers blood pressure, a major component in determining the risk of heart disease. The more pressure blood exerts on artery walls, the harder it is for your heart to pump efficiently. Any time you get your heart pumping harder, like when you go for a run or even a fast walk, your heart muscle gets exercise. It needs to pump up to 10 times more blood to a muscle group that's exercising than to one at rest [source: MSNBC]. And like your biceps, the heart muscle gets stronger from repeated exertions. A stronger heart has an easier time pumping blood, so it can relax more. With relaxation, arteries expand, creating more room for blood to flow.

­Exercise also affects both blood pressure and coronary artery disease because it affects triglyceride levels and cholesterol levels. Triglycerides, like cholesterol, are fatty substances that travel through our blood to our cells. High triglyceride and LDL cholesterol levels make it more likely that fats will build up on artery walls, raising blood pressure and restricting blood flow. HDL cholesterol, or "good cholesterol," has the opposite effect: It prevents fatty buildup on artery walls. Studies show conclusively that exercise lowers triglyceride levels and raises levels of HDL (good) cholesterol. Exercise also seems to decrease the amount of LDL (bad) cholesterol in the body, although those results are more mixed.

Just how much exercise you need in order to help your heart varies. Overall, a good guideline is 30 minutes of aerobic exercise every day, although three days a week will also provide significant benefits. Research has shown that resistance exercise (like weight training) also improves heart health, although somewhat less than aerobic activity.

While in most cases, more exercise is better, it also increases the risk of injury, so overdoing it is a bad idea. People with medical conditions, people on medication and senior citizens should always consult a doctor before starting an exercise program to make sure they're healthy enough to handle the heart and body strain.

But perhaps the most important thing to keep in mind is that any exercise is better than no exercise. Although moderate-to-vigorous aerobic exercise is best, low-strain activities like yard work and playing golf regularly will also help your heart. You needn't run marathons to reduce your risk of heart attack. If you just get up and move around more, your heart will be better off.

For more information on heart health and related topics, look over the links on the next page.


Lots More Information

Related HowStuffWorks Articles

More Great Links

  • The Exercise and Cholesterol Controversy. University of New Mexico. http://www.unm.edu/~lkravitz/Article%20folder/cholesterol.html
  • Exercise can help a bad heart repair itself. MSNBC.com. Sept. 5, 2007. http://www.msnbc.msn.com/id/20606123/
  • Heart Disease Prevention and Exercise. WebMD. http://www.webmd.com/heart-disease/heart-disease-prevention-exercise
  • How Much Exercise Do You Need to Prevent Heart Disease? Health.com. http://www.health.com/health/condition-article/0,,20188246,00.html
  • Physical Activity. American Heart Association. http://www.americanheart.org/presenter.jhtml?identifier=4563