Running may help burn calories, but when it comes to preventing diabetes and obesity, pumping iron might have the edge, according to preclinical findings from Virginia Tech scientists at the Fralin Biomedical Research Institute at VTC.

The research, published Oct. 30 in the Journal of Sport and Health Science, compared the effects of endurance and resistance exercise in mice fed a high-fat diet, a widely used model of obesity, hyperglycemia, and Type 2 diabetes.

A team led by exercise medicine researcher Zhen Yan found that while both running and weightlifting helped the body clear excess sugar from the blood, resistance training was more effective in reducing subcutaneous and visceral fat, improving glucose tolerance, and lowering insulin resistance — key factors in preventing and managing diabetes.

“We all want to live a long, healthy life,” said Yan, professor and director of the institute’s Center for Exercise Medicine Research. “We all know the benefits of regular exercise. There is plenty of evidence in humans that both endurance exercise, such as running, and resistance exercise, such as weightlifting, are effective in promoting insulin sensitivity.” 

But while both support metabolic function, a rigorous side-by-side comparison was lacking. Is one type of exercise better than the other? 

What they did

To conduct the first direct, controlled comparison, members of the research team built something that had not previously existed: a mouse model of weightlifting.

In this model, mice lived in specially designed cages where food was accessed through a hinged, weighted lid. To eat, the mice had to lift the lid while wearing a small shoulder collar, causing a squat-like movement that engaged the muscle contractions people use during resistance exercise. The load was gradually increased over several days, mimicking progressive strength training.

For the endurance group, mice were given open access to a running wheel, an established model of aerobic exercise. Control groups included sedentary mice on either a normal or high-fat diet.

Over eight weeks, the researchers monitored weight gain, body composition, and fat distribution. They tested exercise capacity with treadmill runs, assessed heart and muscle function, and measured how well the mice regulated blood sugar. They also analyzed skeletal muscle tissue to study insulin signaling at the molecular level.

Using their novel model of resistance exercise, team members were able to directly compare how the two training styles affect obesity, blood glucose, and insulin sensitivity in a way that closely mirrors human exercise.

“Our data showed that both running and weightlifting reduce fat in the abdomen and under the skin and improve blood glucose maintenance with better insulin signaling in skeletal muscle,” Yan said. “Importantly, weightlifting outperforms running in these health benefits.”

Why this matters

Diabetes and obesity are major public health challenges, fueled by sedentary lifestyles and high-fat diets. The findings underscore decades of clinical trials that show endurance, resistance, and high-intensity interval training all reduce HbA1c—a key measure of long-term blood sugar control — while also lowering body mass index, blood pressure, and improving quality of life.

The new Virginia Tech study, which also involves collaborators from the University of Virginia, helps fill a critical gap by directly comparing voluntary running and weightlifting in a controlled, preclinical model of diet-induced obesity.

“The findings also bring good news for people who, for any number of reasons, cannot engage in endurance-type exercise,” Yan said. “Weight training has equal, if not better, anti-diabetes benefits.”

The researchers also saw changes in skeletal muscle signaling pathways that could inform new drug therapies for Type 2 diabetes.

Interestingly, the benefits of resistance training were not explained by changes in muscle mass or exercise performance, suggesting unique metabolic mechanisms at play.

Yan said the study underscores the idea that, while popular drug interventions like GLP-1 agonists can help with diabetes management and weight loss, they do not replace the unique, accessible, and comprehensive benefits of a well-balanced exercise program. 

“The take-home message is that you should do both endurance and resistance exercise, if possible, to get the most health benefit,” said Yan, who is also a professor in the Department of Human Nutrition, Foods, and Exercise in the College of Agriculture and Life Sciences at Virginia Tech. 

This research was supported by the grants from the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health and the Red Gates Foundation.

Original study: doi.org/10.1016/j.jshs.2025.101100