Metformin-exercise combination may be ineffective for type 2 diabetics

Both exercise and the common type 2 diabetes medication metformin are known to dramatically reduce blood sugar levels in diabetics. So starting patients on therapies that involve the use of the drug and frequent physical activity has long been supposed to be a valuable tool in fighting high blood sugar.

However, new research published in the journal Diabetes Care indicates that the effects of metformin and exercise may actually cancel each other, potentially leading to even worse blood sugar control in patients with type 2 diabetes.

It is widely believe that metformin lowers glucose levels by activating exercise-like pathways in the metabolic system. The researchers said that when a person on the medication is physically active, this may result in counter-regulatory reactions that cancel each other out.

Normand Boule, who led the investigation, explained the reaction this way: Both metformin and exercise lower blood sugar levels independently. However, when a person on the medication is physically active, it may trigger a process in the body that is intended to prevent glucose levels from dropping too far, which could be dangerous.

For the study, researchers from the University of Alberta tracked the glucose levels of 10 men and women over a period of 28 days. During this time, participants were given either metformin or a placebo. On the last day of the study, individuals were asked to participate in 40 minutes of exercise.

As expected, the results showed that those taking the metformin experienced significant blood sugar reductions. However, when these participants exercised, their glucose levels were much higher.

This was a surprising result for the researchers. They said they were expecting to see the beneficial effects of metformin and exercise multiply. The fact that they actually nullify each other was not the outcome the team was looking for.

"What we've learned is that the relationship between exercise and metformin is complex, and this opens the door for more research to examine how different treatments work together," Boule said.