Independent and combined effects of exercise training and metformin on insulin sensitivity in individuals with prediabetes

Steven K. Malin, Robert Gerber, Stuart R. Chipkin, Barry Braun

Research output: Contribution to journalArticlepeer-review

124 Scopus citations


OBJECTIVE - Physical activity or metformin enhances insulin sensitivity and opposes the progression from prediabetes to type 2 diabetes. The combinationmay bemore effective because each treatment stimulates AMP-activated protein kinase activity in skeletal muscle. We evaluated the effects of exercise training plus metformin on insulin sensitivity in men and women with prediabetes, compared with each treatment alone. RESEARCH DESIGN AND METHODS - For 12 weeks, men and women with prediabetes were assigned to the following groups: placebo (P), 2,000 mg/day metformin (M), exercise training with placebo (EP), or exercise training with metformin (EM) (n = 8 per group). Before and after the intervention, insulin sensitivity was measured by euglycemic hyperinsulinemic (80 mU/m 2/min) clamp enriched with [6,6- 2H]glucose. Changes due to intervention were compared across groups by repeated-measures ANOVA. RESULTS - All three interventions increased insulin sensitivity (P < 0.05) relative to the control group. The mean rise was 25-30% higher after EP than after either EM or M, but this difference was not significant. CONCLUSIONS - Insulin sensitivity was considerably higher after 12 weeks of exercise training and/or metformin in men and women with prediabetes. Subtle differences among condition means suggest that adding metformin blunted the full effect of exercise training.

Original languageEnglish (US)
Pages (from-to)131-136
Number of pages6
JournalDiabetes care
Issue number1
StatePublished - Jan 2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism
  • Advanced and Specialized Nursing


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