It's known as silent ischemia: No chest pain; in fact there are no symptoms at all before a heart attack. For people with type 2 diabetes, this is a common condition -- one that doctors should test for, new research shows.

. , writes researcher Frans J. Wackers, MD, a professor of cardiovascular medicine with Yale University School of Medicine in New Haven, Conn.

People with diabetes who are at high risk for heart disease -- men who are smokers or have high blood pressure for example -- should get a treadmill stress test for heart disease, he says.

According to the American Diabetes Association (ADA) guidelines, doctors should perform stress tests to check for coronary artery disease in people with diabetes who have two or more risks factors.

Doctors have had difficulty detecting early-stage heart disease in diabetes patients because there is nerve damage throughout the body. Therefore, chest pain -- which is the heart's signal that it's not getting sufficient blood and oxygen -- is dampened considerably.

This is the first study to examine how common asymptomatic heart disease is in people with type 2 diabetes and how effective the screening guideline set by the ADA is.

Wacker's study involved more than 1,000 volunteers in 14 centers throughout the U.S. and Canada -- all about 60 years old, with type 2 diabetes, and with no known or suspected heart disease.

Some had a stress test (like a treadmill test) to determine how well the heart can handle exercise. In this case, the test determines whether people with type 2 diabetes experienced signs of heart problems because of a lack of oxygen being delivered to the muscles. The test shows if blood supply is reduced, which should cause chest pain.