Here’s news straight from the heart: The American Heart Association (AHA), which for years singled out only smoking, high blood pressure, and high blood cholesterol as major risk factors for coronary disease, has added a fourth factor—physical inactivity—to those that can be controlled with changes in lifestyle.

For the 70 million Americans afflicted with coronary disease, and the 1.5 million who suffer a heart attack each year, this is definitely good news. Not only can exercise help prevent heart attacks, it can improve the chances of survival for people who have already suffered an attack. It also decreases the occurrence of second attacks. On the other hand, people who avoid all physical activity run a 30 percent higher than normal risk of heart disease, says the AHA.

In addition to increasing the strength of the heart, exercise aids in weight control, increases the benefits of a low-fat diet, and improves the “good” to “bad” cholesterol ratio. It has also been shown to deter diabetes (a disease linked to heart disease), and it sometimes lowers high blood pressure.

By exercise, the AHA is not talking about training for a marathon. Simply doing things that require a little extra exertion—taking the stairs rather than the elevator, pumping your own gas, enjoying a nice walk—can improve your cardiovascular health. To achieve optimal benefits, the AHA recommends 30 to 60 minutes of either vigorous or casual exercise, three to four times a week.