Cardiovascular fitness may predict the odds of a future heart attack in men and women with no apparent signs of heart disease, a large study suggests.

Researchers found that of more than 26,000 adults with no symptoms of heart disease, those who showed the greatest endurance on exercise tests had the lowest risk of suffering a heart attack or stroke over the next 10 years.

Men with the highest fitness levels were 31 percent less likely than their least-fit counterparts to have a non-fatal heart attack or stroke, or to require an invasive procedure for heart artery blockages. The risk for men with moderate fitness levels fell between the highest and lowest fitness groups.

A similar pattern emerged among women, the study authors report in the American Journal of Epidemiology.

By now, most people may have heard the familiar advice to get 30 minutes of moderate exercise each day for the sake of their health. The new findings underscore how important fitness -- and, therefore, regular exercise -- is in heart health, according to Dr. Xuemei Sui, the study's lead author.

Other findings in this same study group, she told Reuters Health, have shown "again and again" the benefits of boosting fitness through exercise.

This includes not only a lower risk of death from cardiovascular disease, but also a lower likelihood of premature death from a range of causes, noted Sui, a research associate at the University of South Carolina in Columbia.

The current findings are based on 20,728 men and 5,909 women who had no symptoms of heart disease when they entered the study, somewhere between 1971 and 2001. At that time, they underwent a treadmill test to gauge their fitness levels, had physical exams and completed questionnaires on their lifestyle habits.

They were then followed for an average of 10 years, during which time 1,512 men and 159 women had a non-fatal heart attack or stroke, or underwent an artery-clearing procedure.

Sui's team found that, even when several other factors were accounted for -- such as age, smoking and weight -- higher fitness levels seemed to protect against heart problems.

The findings, according to the researchers, argue for the value of more routine exercise testing of people with no symptoms of heart disease. Those test results, they say, could be used along with traditional risk factor assessment - like measuring blood pressure and cholesterol -- to help predict a person's odds of heart trouble down the road.

Right now, however, it's not standard practice for people without heart disease symptoms to undergo exercise testing. The test is generally reserved for people who have symptoms, such as chest pain, or a high risk of heart disease, Sui noted.