Study Reveals Metformin May Hinder Diabetes Patients’ Exercise Benefits

Research from Rutgers University indicates that the widely prescribed diabetes medication, metformin, may undermine the health benefits associated with exercise for patients with type 2 diabetes. A study involving 72 adults at elevated risk for metabolic syndrome found that metformin inhibits improvements in cardiovascular health typically gained through physical activity.

According to the study, published in The Journal of Clinical Endocrinology & Metabolism, participants taking metformin showed no significant enhancements in blood vessel function and aerobic fitness after a 16-week exercise regimen compared to those not on the medication. This raises concerns for the more than 20 million Americans currently using metformin to manage their diabetes.

The double-blind, placebo-controlled trial divided participants into four groups: those engaging in high- and low-intensity exercise while taking either a placebo or metformin. The findings revealed that individuals in the placebo groups experienced meaningful improvements in aerobic fitness levels, while the metformin groups saw no such progress.

Impacts on Vascular Health and Insulin Sensitivity

The study aimed to assess how exercise impacts vascular insulin sensitivity, an important factor in glucose regulation and cardiovascular health. Participants’ blood vessel function was evaluated by examining how well their blood vessels responded to insulin stimulation, which helps with nutrient and oxygen uptake after meals.

Lead author Steven Malin, a professor in the Department of Kinesiology and Health at Rutgers, noted that the assumption underlying diabetes treatment has been that medication combined with lifestyle changes would yield better health outcomes. Yet, he emphasized that evidence suggests metformin significantly blunts the expected benefits from exercise.

“Most health care providers assume one plus one equals two,” Malin stated. “The problem is that most evidence shows metformin blunts exercise benefits.”

Participants who were not on metformin showed improvements in body fat levels and vascular insulin sensitivity, while those taking the drug did not exhibit similar enhancements. Those on metformin also experienced worse inflammatory markers and fasting glucose levels, indicating a lack of improvement in overall health.

Rethinking Diabetes Management Strategies

Since the introduction of metformin in diabetes treatment, exercise has been recommended as a vital part of managing the condition. Regular physical activity is known to enhance insulin sensitivity, lower blood glucose levels, and reduce the risks associated with obesity, heart disease, and stroke.

Despite the study’s small scale, it raises significant questions about the effectiveness of combining metformin with exercise for diabetes management. “If you exercise and take metformin and your blood glucose does not go down, that’s a problem,” Malin warned. He also highlighted the potential long-term health risks that could arise if patients do not gain fitness from their exercise efforts.

While the exact mechanism by which metformin interferes with exercise benefits remains unclear, researchers speculate it may relate to how the drug suppresses mitochondrial function, thereby reducing oxidative stress and impacting overall exercise outcomes.

The study’s findings do not suggest patients should discontinue metformin or exercise. Instead, they underscore the need for healthcare providers to closely monitor individuals who are not achieving expected health improvements through exercise.

Malin concluded, “We need to figure out how to best recommend exercise with metformin. We also need to consider how other medications interact with exercise to develop better guidelines for doctors to help people lower chronic disease risk.”

Further research is essential to explore this interaction and develop strategies that maximize the health benefits for those with diabetes, ensuring their hard work in managing their condition is rewarded.