Exercise, Chronotype, and Prediabetes

Inclusion Criteria: 1. Able to provide signed and dated written informed consent prior to any study specific procedures 2. Adult men and women aged between more than 18 and ≤ 75 years 3. Body mass index (BMI) of 25 - 35 kg/m2 4. Stable weight (no weight loss or gain \> 3 kg in the past 3 months) 5. Pre-diabetes defined as an isolated impaired glucose tolerance or a combination of impaired glucose tolerance and impaired fasting glucose (values are based on the American Diabetes Association (ADA): 1. impaired glucose tolerance (plasma glucose 140 mg/dL to 199 mg/dL, 120 minutes after consumption of 75g of glucose) 2. impaired fasting glucose (fasting plasma glucose 100 mg/dL to 125 mg/dL) 6. Morning (Morningness-Eveningness Questionnaire \[MEQ\] score ≥ 59) or evening (MEQ score ≤ 41) chronotype Exclusion Criteria: 1. Previously diagnosed with type 2 diabetes 2. Moderate to severe anemia (hemoglobin \< 10 g/L) 3. Uncontrolled hypertension 4. Abnormal electrocardiogram (ECG) at rest judged by the study physician 5. Pregnancy or breastfeeding 6. HIV, hepatitis B, or C infection 7. Disorders of blood clotting or wound healing 8. Positive history of venous thrombosis (contraindication for clamp) 9. Hypersensitivity to local anesthetics (contraindication for fat/muscle biopsies) 10. Night shift work in the last 3 months 11. Travel across \> 1 time zone in the last 3 months 12. Participation in another clinical trials that may possibly hamper the study results 13. Engagement in structured exercise activities \> 2 hours a week 14. Any acute condition, exacerbation of chronic condition, or medical history that in the investigator's opinion would interfere with the study 15. Any contraindication for MRI scanning 16. Medication use known to hamper safety during the study procedures 17. Non-German speaking