Carrying extra fat ups your risk of heart disease, even if you're fit.

Some experts have said that Americans should focus more on improving fitness than conquering fatness. But this current study suggests this may not be the best strategy.

The finding comes from a study of 135 healthy men with an average age of 48. Some of the men were couch potatoes, some were active, and some were amateur endurance runners who got vigorous exercise more than five times a week.

For all the men, fatness -- in terms of actual body fat, waist size, and body mass index -- was consistently linked to signs of heart disease risk. University of Colorado researcher Phillip E. Gates, PhD, and colleagues report the findings in the April 19 issue of Circulation.

"We had men with high body fat among those who were endurance trained," Gates said at an American Heart Association news conference. "Did we have fit people who also were fat -- and did they have risk factors for heart disease? The answer is yes, because fatness predicted risk better than fitness in the entire group of men."

Stay Fit, But Lose Excess Weight, Too

None of the men in the study had any sign of actual heart disease. And Gates' team didn't just take their word for how fit they were. Each man worked out on a treadmill until exhausted, while the researchers measured their heart rates and oxygen consumption.

The researchers also gave the men tests for 18 different blood and metabolic factors linked to future risk of heart disease.

The men with the most fat had the most heart risk factors, regardless of how fit they were.

"People with fatness are likely to increase their [heart disease] risk even if they are aerobically fit," Gates says. "We think it is important to prevent weight gain and promote weight loss. Weight management and weight loss is important for reducing heart disease risk. Exercise should not be seen as a separate thing, but as part of this strategy."

By Daniel J. DeNoon, reviewed by Michael W. Smith, MD

SOURCES: Christou, D. Circulation, April 19, 2005; vol 111: pp 1904-1914. News conference, American Heart Association. Phillip E. Gates, PhD, University of Colorado Health Sciences Center.