SNS activity measurements (multiunit and single-unit microneurographic recordings of MSNA, whole-body norepinephrine spillover, and abdominal adipose tissue and skeletal muscle interstitial noradrenaline concentration determined by microdialysis) will be made before and during an oral glucose tolerance test, together with haemodynamic (calf blood flow measured by venous occlusion plethysmography) measurements. Changes in fat mass will be quantitated by DEXA scan. Metabolic measurements will include resting metabolic rate, insulin sensitivity, lipid profile, non-esterified fatty acids, plasma and interstitial adipokines/cytokines.