When most Americans think about someone with heart disease, they don’t envision Braxton. “You think it’s some older guy, retired,” says the R&B singer and songwriter, who is now serving as a spokeswoman for Campbell Soup Co.’s GoRedWithCampbells.com. (The company is donating $1 to the American Heart Association’s Go Red for Women campaign for every person who votes for his or her favorite red dress before Jan. 30.) “You can be in your 30s, less than 115 pounds, exercise—and have heart disease.”

Indeed, cardiovascular disease kills more than 460,000 American women a year—more than any other cause of death. “It’s an equal opportunity killer,” says New York University cardiologist Jennifer Mieres, a national spokesman for the American Heart Association’s Go Red for Women campaign and author of the new book “Heart Smart for Black Women and Latinas” (St. Martin’s Press). “My whole message is to tell women, yes, they’re vulnerable.” In a 2006 American Heart Association survey, 77 percent of Caucasian women knew that heart disease was the biggest killer of women, but only 38 percent of black women and 34 percent of Latina women were aware of it. Yet African-American women are at greater risk for a heart attack, partly because of earlier exposure to risk factors such as high blood pressure and diabetes.

The most common type of heart disease is coronary artery disease: blockages of the arteries that supply the blood to the heart. As a result, women can suffer from heart attacks, or their hearts can fail to pump properly. Some women suffer from irregular beating of the heart, others from valves that don’t work properly, others—like Braxton—from pericarditis. Typically, postmenopausal women are at greater risk of heart problems, but younger women who smoke also suffer from a higher incidence of trouble. Heart attack warning signs include chest discomfort that feels like squeezing or uncomfortable pressure, discomfort in the arms, back, neck, jaw or stomach, shortness of breath, nausea or lightheadedness. Call 911 to get to the hospital as fast as possible.

Women can take steps to help prevent coronary disease, including not smoking, exercising at least 30 minutes a day, losing weight if necessary and eating a diet rich in fruit and vegetables. They may want to talk to their doctors about taking a daily dose of aspirin.

See the National Institutes of Health Web site to plug in your cholesterol, blood pressure and other information and estimate your 10-year risk of suffering a heart attack or coronary death. Or check out the American Heart Association Web site for the Go Red for Women heart checkup. After all, no one is immune. “We are all at risk for heart disease,” says New York University cardiologist Nieca Goldberg, author of “Dr. Nieca Goldberg’s Complete Guide to Women’s Health” (out this month from Ballantine Books). “You need to take care of your heart.”