New research indicates that metformin, which is one of the most used drugs against diabetes, can negate the benefits of physical exercise.
A metforminone of the most prescribed medications for type 2 diabetes, may be compromising the very health benefits that patients hope to achieve from exercise.
In a controlled clinical trial, scientists found that metformin appears significantly reduce cardiovascular benefits and metabolic levels normally obtained with regular physical activity.
The , published in the Journal of Clinical Endocrinology & Metabolism, involved 72 adults at high risk of metabolic syndrome. Participants were divided into four groups: high-intensity exercise with metformin, high-intensity exercise with placebo, low-intensity exercise with metformin, and low-intensity exercise with placebo.
Over the course of 16 weeks, researchers assessed blood vessel function, insulin sensitivity, markers of inflammation, blood glucose levels, aerobic fitness and body composition.
Lead author Steven Malin, professor of kinesiology and health, said the findings challenge the long-held belief in diabetes treatment that combining medications and exercise yields cumulative benefits. “Most healthcare professionals assume that one plus one equals two,” Malin said. “The problem is that most evidence shows that metformin attenuates the benefits of exercise”.
Participants who exercised while taking a placebo showed significant improvements in aerobic fitness, vascular insulin sensitivity, and fasting glucose levels. In contrast, those taking metformin did not show any improvement in physical fitness despite completing the same exercise regimen. Most surprisingly, your blood vessels did not respond to insulin in a beneficial way normally triggered by physical activity, a key factor in cardiovascular protection. Measures of inflammation and blood glucose control were also worse among metformin users.
The researchers used benchmark metabolic tests, including euglycemic-hyperinsulinemic clamps and imaging techniques to assess blood vessel dilation and microvascular insulin sensitivity. They found that although exercise alone improved vascular function “regardless of intensity,” adding metformin eliminated these gains.
The study suggests that the mechanism of action of metformin, which suppresses certain mitochondrial functions to reduce oxidative stress, may inadvertently interfere with the mitochondrial adaptations that cause exercise to improve physical fitness and cardiovascular health, explains the .
Malin warned that the findings are not a reason to interrupt medication or physical activity, but rather a sign that some patients may require more rigorous monitoring if the expected improvements do not occur.
“We need to figure out the best way to recommend exercise in conjunction with metformin,” he said. “And we need to understand how others medications interact with exercise to create better guidelines for reducing the risk of chronic diseases.”
