Research into the causes and cures of America's No. 1 killer, heart disease, is turning up some happy, helpful and hopeful news.

Better Homes and Gardens magazine offers the following current examples:

-Those heart attack victims who bounce back the quickest seem to have a relatively low risk of suffering another attack. Researchers working at Stanford University studied male patients from the Kaiser Permanente medical centers in San Francisco.

Each of the patients had suffered a so-called "uncomplicated" heart attack. These were people with no signs of angina (pain upon exertion) or congestive heart failure (when the heart pumps poorly) three days after their heart attacks. Half of all heart attack victims at Kaiser Permanente fell into this category.

The patients' own doctors predicted 20 percent of them would have another heart attack within six months. In fact, only 3.5 percent had second heart attacks within that period. The report's author, Dr. Charles Dennis of Stanford, pointed out this risk isn't much greater than the risk for the average man in the same age range, about 1 percent.

-A study of "professional walkers" (letter carriers) may hold the key to lowering the risk of heart disease. Dr. Timothy C. Cook of the University of Pittsburgh found positive results in carriers who walked an average of 5 miles a day.

These carriers had higher levels of the "good" (HDL) cholesterol than nonwalkers. HDL cholesterol helps keep fatty deposits from choking off arteries and thereby lowers the risk of having a heart attack. Studies have shown that vigorous aerobic exercise, heart-pounding workouts, also raise HDL cholesterol levels. Milder forms of exercise, including walking, can produce similar results.

For those interested in starting a walking program, experts suggest starting slowly, 20 minutes a day is fine. Gradually work up to about an hour a day, then slowly build up the speed until 4 miles can be covered in an hour.

-Millions of Americans are aiming for a blood cholesterol number of less than 200 milligrams per deciliter of blood. According to the American Heart Association, these efforts offer a 2-to-1 payoff.

For every 1 percent a person's cholesterol number is reduced, the odds of getting heart disease is reduced by 2 percent. A simple and painless test will yield one's cholesterol number.

-Reducing cholesterol numbers is a bit more complicated than doctors originally believed. Cutting down on foods high in cholesterol (egg yolks and liver, for instance) isn't as important as scaling back on saturated fat.

Animal fat is relatively high in saturated fat as are palm and coconut oil. But don't banish any foods from a diet. Instead, emphasize grains, nonfat dairy products, vegetables, fruits, fish and poultry.