Research has shown that exercise has great benefits for people with type 2 diabetes.
But when a University of Alberta researcher looked at the dual impacts of exercise and metformin - two of the most commonly prescribed modalities for glucose control -the outcome was less beneficial.
"The study had three objectives: we wanted to look at the effect of metformin on exercise in people with type 2 diabetes, examine the effect of exercise on metformin concentrations in the body, and finally to look at the effects of metformin and exercise on glucose control, which is essential for people with diabetes," said Dr. Normand Boule, an Associate Professor in the Faculty of Physical Education and Recreation at the University of Alberta.
Ten men and women between 30 and 65 with type 2 diabetes, but not taking glucose-lowering medication or insulin for their condition, were recruited into the study.
Participants were randomly assigned to take metformin or a placebo for the first 28 days of the study, then crossed over so those taking the placebo received metformin and vice versa for a second 28-day period.
On days 27 and 28, participants spent six hours in the exercise physiology lab and performed different tests, including approximately 40 minutes of exercise on day 28.
"As expected, in our study metformin lowered the blood glucose concentrations measured during a two-hour period after lunch. But we found that on the non-exercise day metformin led to better glucose control after lunch than on the day our participants took metformin and exercised," said Boule.
Boule thinks that because both metformin and exercise act to lower glucose levels, the combination may have triggered a counter regulatory response by the body to prevent glucose levels dipping too much.
This study was recently published in the journal Diabetes Care.