Why is exercise important for heart health?

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.