This is a randomized, placebo controlled, double blind study. 60 men and women over the age of 55 with indications of pre-diabetes will be recruited for participation and randomly assigned to one of four 12 week exercise training programs: 1)Supervised aerobic exercise 3 days per week followed by a carbohydrate drink along with daily oral administration of Metformin. 2) Supervised aerobic exercise 3 days per week followed by a protein drink along with daily oral administration of Metformin. 3) Supervised aerobic exercise 3 days per week followed by a carbohydrate drink along with daily oral administration of matching placebo. 4) Supervised aerobic exercise 3 days per week followed by a protein drink along with daily oral administration of placebo.
Daily administration of Metformin will begin as one 500 mg tablet for the first week and will increase by 500 mg/day/week until reaching 2000 mg/day by week 4 during a 12 week exercise training program. The titration dosing scheme and taking metformin/placebo with meals will help reduce the most common side effects (i.e.,gastrointestinal discomfort). If participants experience gastrointestinal discomfort, the dose will be lowered to 1500 mg/day.
