Pumping iron could help protect young people at risk of type 2 diabetes from developing the disease, a study hints.

Overweight Latino 15-year-olds who worked out with weights twice a week for 16 weeks showed a significant improvement in their ability to respond to the key blood sugar regulating hormone insulin.

A reduction in insulin sensitivity can signal the early stages of diabetes, and is associated with obesity.

Resistance training has been shown to increase insulin sensitivity in adults, but it is not clear how weight lifting may affect insulin response in young people, Dr. Michael A. Goran of the University of Southern California in Los Angeles and colleagues note in a report.

To investigate, they assigned 22 overweight teenage boys to twice-weekly weight lifting workouts for 16 weeks or no exercise.

After the program, the boys who lifted weights showed gains in upper and lower body strength. Their insulin sensitivity increased by 45 percent, while insulin sensitivity among their sedentary counterparts actually fell about 1 percent.

The effects on insulin sensitivity remained even after the researchers accounted for the increase in muscle mass caused by exercise, suggesting that the workouts boosted insulin sensitivity by other means, the researchers note. And a longer intervention, they add, could produce additional benefits.

“Given the relatively limited success in terms of fat loss and health improvements following even the most intensive endurance exercise interventions in overweight children, the increases in insulin sensitivity, coupled with our high attendance and compliance rates, suggest that resistance training may be a viable and efficacious exercise modality to improve metabolic health in overweight youth,” the researchers conclude.

SOURCE: Medicine & Science in Sports & Exercise, 2006.