Our aim is to investigate the effects of a 12-week structured aerobic exercise on fasting and 2 h glucose, insulin and lipid concentrations in sedentary overweight subjects in whom impaired fasting glucose and/or impaired glucose tolerance was observed for the first time.

Study type: Interventional

Study design: Randomized

Endpoint classification: Changes in fasting and 2 h glucose, insulin and lipid concentrations

Intervention model: Parallel assignment

Masking: Open label

Primary purpose: Prevention and dose response assessment of exercise on glucose and lipid metabolism

Condition: Prediabetes

Intervention: Supervised exercise - The training sessions of the intervention group are carried out indoors 3 times a week for 3 months and supervised by an exercise instructor and physician. Each session last for 60 min and include a 5-min warm-up and stretching, a 20-min walking at speeds 2-4 km/h depending of the participant's physical condition, a 5-min stretching and balance training, a 20-min walking, and a 10-min stretching and balance training. After 1.5 months the 5-min stretching and balance training between the two 20-min walkings is excluded, and the walking time become 45 min.

No intervention: control group; couseling at baseline. Participants of the control group are advised to continue their usual physical and dietary habits.

Experimental: 1 -supervised exercise intervention. No intervention: 2 - standard counseling at baseline.

Inclusion Criteria:

• prediabetes determined by 2 hr oGTT

Exclusion Criteria:

• any functional limitation or chronic disease that might have limited the physical exercise and testing
• vigorous physical activity/exercise as revealed by questionnaire and physician exam