CIRcadian Rhythms and CortisoL. Effects on Substrate Metabolism and Clock Gene Expression and Functioning

Inclusion Criteria: * Male sex * BMI 20-30 kg/m2 * Written informed consent Exclusion Criteria: * Any chronic disease requiring daily medication excluding atopic skin or hay fever * Alcohol consumption \>21 units per week * Strong CYP3A4 inhibitors or inducers * Use of glucocorticoid (GC) formulations: Inhaled corticosteroids, intra-articular or intramuscular injections, steroid creams European steroid group IV-V used in the genital area * Permitted glucocorticoid formulations: eye-drops, nasal spray, GC creams European steroid group I-III, and European steroid group IV-V used in the non-genital area only * Shift work * Severe claustrophobia * Use of melatonin * Previous diagnosis of a sleep disorder * Known severe sleep apnea (\>30 respiration breaks/hour over 10 seconds) * Deemed unable to complete the study safely by investigator