RALEIGH, N.C. — In most gyms, you will hear the chant of instructors, the whirr of treadmills and the clang of weights, but what do those activities do for the beat of the heart?

Mike Hauser used to be a couch potato with borderline high cholesterol. A couple years ago, he joined a study at Duke University to see how aerobic training might improve his health. The completed study helped define the effects of walking on body fat.

In study participants, walking just 30 minutes a day prevented weight gain. More intense workouts led to weight loss.

"[It] just made me feel better. It gave me a lot more energy. I sleep better at night," Hauser said.

Now, researchers at Duke University and East Carolina University are enrolling study participants to measure the benefits of resistance training. They know straining against opposing weights builds muscle cells.

"We think by increasing the numbers and the size of those cells, one then can handle cholestrol and handle glucose better and therefore improve health," Duke cardiologist Dr. Bill Krause said.

The 4½-year study will compare aerobics to resistance training. Researchers will also study a group that combines both. For more information about participating in the study trial, you can call Duke University at

(919) 681-9000

or East Carolina at

(252) 328-5490

.