Inclusion Criteria:  Signed informed consent Western European origin or of Siberian origin BMI between 18.5 and 35 kg/m2 Generally healthy (determined by dependent physician)  Exclusion Criteria:  Smoking Active, uncontrolled cardiovascular disease or cancer Raynaud's disease Participation in another biomedical study within 1 month before the first study Cold-acclimated (Western European group), such as takes daily extended cold baths, works in a refrigerated environment, or regular cold-water swimming within 1 month of starting the study Medication use known to hamper subject's safety during study procedures Abuse of alcohol or drugs