In the present study, we performed a comprehensive investigation of fatty acid metabolism, insulin and incretin response to OGTT, glucose tolerance, insulin sensitivity, and autonomic nervous system activity (heart rate variability, HRV) in men found to have severe OSA compared with men without sleep apnea, and this was done under normal daytime conditions regardless of recent OSA episodes. The gene discussed is INS; the disease is obstructive sleep apnea syndrome.