Senior author Dr. Sandor J. Kovacs studied a group of healthy, overweight but not obese, middle-aged men and women. Kovacs found that a yearlong regimen of either calorie restriction or exercise had positive effects on heart function.

The study found the loss of weight resulted in heart function being restored to a more youthful state so during the heart's filling phase it took less time for participants' hearts to relax and fill with blood.

"As we get older, our tissues become more fibrotic as collagen fibers accumulate," study co-author Dr. John O. Holloszy said in a statement. "So the arteries and heart muscle stiffen, and the heart doesn't relax as well after contracting."

By the end of the yearlong study, both the calorie restriction and exercise groups of volunteers lost 12 percent of their weight and 12 percent of their body mass index. In both groups, participants' hearts responded to the weight loss by gaining the ability to relax more quickly, recovering some of the elasticity characteristic of younger heart tissue.

The findings are published in the American Journal of Physiology.