Medwire News: Exercise training increases insulin sensitivity in individuals with prediabetes, report researchers.
Surprisingly, the addition of metformin to exercise doesn't accentuate this improvement and may even blunt the full effects of exercise training, they say.
"The American Diabetes Association (ADA) strongly recommends exercise as a cornerstone therapy for diabetes prevention and, recently, suggested that some individuals with prediabetes be considered for metformin treatment," write Barry Braun (University of Massachusetts, Amherst, USA) and team.
However, "the efficacy of combining lifestyle modification with metformin has been tested only a few times," they add.
As reported in the journal Diabetes Care, the researchers randomly assigned 32 otherwise healthy individuals with impaired glucose tolerance to receive placebo (P), 2000 mg per day of metformin (M), exercise training with placebo (EP), or exercise training with metformin (EM), for a period of 12 weeks.
The exercise training comprised three 60-75-minute sessions per week of aerobic and/or resistance work.
Insulin sensitivity was measured by euglycemic-hyperinsulinemic clamp at baseline and at the end of the intervention.
Relative to baseline, M, EP, and EM all significantly enhanced insulin sensitivity among the participants, compared with P.
However, the increase in insulin sensitivity was 25% to 30% higher with EP than it was with EM or M, although this difference was not significant.
Nevertheless, the blunting effect of adding metformin to training "has potential clinical relevance and is worth considering," write Braun et al.
They say that despite the lack of additive effects on insulin sensitivity, combining metformin with training, as recently recommended by the ADA, may be a potentially useful strategy to prevent the transition from prediabetes to diabetes.
"Further work is required to understand the utility of combining metformin with training in regard to its impact on insulin sensitivity and other aspects of cardiometabolic health," they conclude.
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