George and his little sister Gayle remember last year, when their grandmother went to the hospital in an ambulance after she had a heart attack. And this spring, their father had to have an operation on his heart to help it work better. Those were scary times, although their grandmother is feeling better now, and their father's operation made him so much stronger that now he can go bicycling with them again.

"If Grandma and Dad both got sick, will that happen to us too?" George wonders.

Doctors know that often heart problems run in families and that children whose relatives are at risk for a heart attack must be especially careful. But the good news is that at your age, it is easier to learn how to stay healthy.

At the Medical College of Virginia Hospitals in Richmond, a group of families is learning how to live so that their hearts stay healthy. In the "Happy Hearts" program, kids who are likely to develop heart disease when they get older and their parents are learning preventive care for their bodies.

The children have high levels of "bad" cholesterol in their blood. This kind of cholesterol clogs up arteries by forming fatty deposits inside them. The tendency to have bad cholesterol is inherited. That means it runs in families. A child whose grandparents or parents had heart disease -- especially early heart disease -- are considered "at risk" for developing it, too. Doctors check these kids for high cholesterol levels early. Kids in the "Happy Hearts" program come from families with a history of heart trouble, and they have elevated cholesterol levels themselves.

Very young children can have high cholesterol, although symptoms don't show up until later in life. High cholesterol is one of those things you can't see. People with it are not more likely to be overweight, for example. But inside their bodies, cholesterol can build up fat deposits that can cause trouble later on.

Doctors all over the country are worried about kids' hearts. They say that if kids keep eating high-fat foods and avoiding exercise, one out of three children born this year is likely to have a serious heart attack before age 60.

The kids in "Happy Hearts" aren't ill, though, says Monica Goble, a pediatrician who directs the Happy Hearts risk-reduction program. "We don't label a child with high cholesterol as a sick child, but as a child who is healthy and whom we're trying to keep healthy," she says.

In the program, families learn to plan menus, to shop for healthy groceries and to order healthy meals in restaurants. They learn the importance of exercise and why smoking cigarettes causes problems in people susceptible to heart disease. After they complete the program, they will come back to the hospital at regular intervals to see how the changes they make affect their health.

What's different about the "Happy Hearts" program? It concentrates on changing the way a whole family eats and acts. So although kids are the focus of the program, everyone benefits.

Children ages 6 to 13 are the major concern of doctors who designed the "Happy Hearts" program. "We try to reach them in pre-puberty or early puberty," says Richard Schieken, a pediatric cardiologist (or kids' heart doctor) at the Medical College of Virginia. He explains that during puberty -- the time between ages 11 and 14 when physical changes happen to boys and girls as they become adults -- the fat deposits that can clog arteries begin to change. They develop into plaques -- deposits that can block arteries and keep enough blood from getting through the heart.

The idea is to prevent the fatty deposits from getting inside the arteries in the first place.

The program allows no more than 30 percent of its calories from saturated fat. (That's the kind in meats, including beef, veal, lamb, pork and ham. It is also in dairy products, like butter, whole milk, cream cheese made from whole milk or cream, and sour cream. Saturated fat also turns up in unexpected places like cereals and processed foods, because some vegetable oils -- including coconut oil, cocoa butter and palm oil -- used in preparing them contain saturated fat.) Doctors know too much saturated fat raises cholesterol.

The National Cholesterol Education Program recommends that all Americans over age 2 -- not just those with a risk of developing heart disease -- should follow a sensible diet that contains less fat, more fruits, vegetables and grains and more skim milk. One way to cut fat is to eat more grains like corn, wheat, oats and rice; breads; cereals and pasta; dried beans and peas; potatoes and all vegetables and fruits.

As the kids in the program are finding out, keeping your heart happy isn't difficult. In fact, it's fun -- and it pays off in the long run.Tips for Parents

Scientists have thought for decades that heart disease can begin in childhood, and several recent studies have confirmed this. However, there is still debate in the medical community over whether to test young children for high cholesterol levels. Some physicians urge that all kids be tested as early as kindergarten; others, including the American Academy of Pediatrics, are more conservative. The academy recommends that only children over age 2 who come from families with a clear history of cardiovascular disease be tested. If a finger-stick test gives a high reading for total cholesterol, then the child should undergo more detailed tests.

Catherine O'Neill is a children's writer.