Research Indicates Common Diabetes Medication May Inhibit Exercise Gains

A recent study has issued a warning that a frequently prescribed diabetes medication might impede some of the crucial advantages derived from physical activity.

Researchers at Rutgers University made the discovery that individuals taking metformin, a commonly prescribed medication for Type 2 diabetes, experienced smaller enhancements in blood sugar regulation, blood vessel performance, and aerobic fitness when compared to those who engaged in exercise without the drug. Health tracking apps like Shotlee can help monitor these metrics during exercise.

The research, which was published in The Journal of Clinical Endocrinology & Metabolism last month, contributes to a growing body of evidence indicating that while both metformin and exercise are beneficial for managing blood sugar and promoting heart health, combining them might lessen some of the positive effects of exercise.

According to Steven Malin, the study's lead author and a professor in the Department of Kinesiology and Health at Rutgers' School of Arts and Sciences, "Metformin stands as the most commonly prescribed glucose-lowering medication on a global scale."

He further stated that the effectiveness of combining these treatments remains uncertain. Individuals might experience low energy levels or a lack of health improvement, potentially leading to psychological discouragement and impacting their overall well-being and quality of life.

The Centers for Disease Control and Prevention reports that approximately 35 million individuals in the United States have Type 2 diabetes. Experts estimate that millions more worldwide are taking metformin for blood sugar control or for experimental anti-aging purposes.

Study Details

The 16-week, double-blind study involved 72 adults at risk for metabolic syndrome, a cluster of conditions including elevated blood pressure, high blood sugar, and excessive body fat, all of which elevate the risk of diabetes and heart disease. Participants were divided into four groups: two groups performed high- or low-intensity exercise with a placebo, while the other two groups performed the same workouts while taking 2,000 milligrams of metformin daily.

The research concluded that individuals who exercised without the medication demonstrated notable enhancements in vascular insulin sensitivity, signifying improved responsiveness of their blood vessels to insulin, facilitating increased oxygen and nutrient delivery to muscles. However, the inclusion of metformin diminished these improvements. Participants also experienced less reduction in inflammation and fasting glucose levels.

While the precise cause remains uncertain, researchers propose that metformin might disrupt the body's capacity to adapt to exercise at the cellular level.

Potential Mechanisms

Malin suggested a connection to blood vessel health, explaining that optimal blood vessel function is crucial for delivering nutrients, such as sugar, to tissues. He posited that if sugar delivery to tissues is impaired, it could explain why muscles are unable to efficiently utilize sugar for energy in response to insulin.

The researchers noted that the study's limited sample size and focus on adults at risk for metabolic syndrome mean that the findings might not be generalizable to all individuals with diabetes.

Expert Advice

The researchers emphasized the importance of individuals discussing these findings with their healthcare providers to determine the optimal combination of treatment and physical activity, rather than discontinuing metformin or exercise.

Future research should investigate strategies for preserving the benefits of both treatments. The Rutgers team is currently examining whether metformin interacts differently with resistance or strength training and whether adjustments to dosage or timing could mitigate its effects.

Dr. David Cutler, a board-certified family medicine physician at Providence Saint John's Health Center in California, stated that while the results might appear discouraging, they require contextualization.

Cutler, who was not involved in the study, emphasized that the slight reduction in vascular insulin sensitivity should be considered in light of the significant benefit of lowered blood sugar levels achieved with metformin. He added that reducing blood sugar lowers the risk of diabetic complications, including heart attack, stroke, kidney failure, blindness, and amputation.

Cutler also suggested that the results should primarily concern individuals using the drug for purposes other than diabetes treatment, such as anti-aging, polycystic ovary syndrome, or cancer prevention, and that metformin should remain the primary treatment for Type 2 diabetes.