Do patients with type 2 diabetes need to exercise in fasting condition to improve glucose regulation?

Exercise training in the fasted state might be a more effective strategy to maximize glycemic control in T2DM patients, as opposed to exercise training in postprandial state.

Entry of program and 3 months later.

Subjects are randomly assigned, by envelope, to three months of exercise training in the fasted state (before breakfast) (n=20) or postprandial state (after breakfast) (n=20). At entry of intervention, and after three months of intervention, following measurements will be executed: fasting blood sample for assessment of glycemic control and lipid profile, euglycemic hyperinsulinemic test, maximal and submaximal cardiopulmonary exercise test, body composition assessment, skeletal muscle biopsy.
All participants perform three individually supervised, endurance exercise sessions per week during a 3-month intervention period. During each training session, walking and cycling exercise is performed, for a total duration of 45 min, at exactly 65% of baseline VO2peak. The exercise training intensity is standardized by continuous heart rate monitoring (Polar, Oy, Finland).
Subjects which are randomized to the exercise intervention in the fasted state will exercise between 07.30-10.00 AM, followed by breakfast within 60 min after exercise. Subjects which are randomized to the exercise intervention in the postprandial state will exercise between 08.30-11.00 AM, after having consumed a breakfast <60 min ago. To standardize breakfast throughout intervention, subjects need to define this breakfast for the training days ahead of intervention, and maintain this breakfast during the entire intervention. Caffeine- and/or carbohydrate-containing beverages are not allowed during this breakfast. The caloric intake and macronutrient content of this breakfast will be calculated for all subjects, and compared between groups. During the exercises session, it is only allowed to drink water. Administration of monosaccharides will only be allowed in case of hypoglycemic symptoms.