Cardiovascular and metabolic disorders represent today one of the main causes of morbidity and mortality in the world. We analysed different physiologic and metabolic disorders associated to metabolic syndrome, defined by NCEP criteria, within one thousand healthy aged subjects recruited from the electoral list of the town of Saint Etienne. Our main results are that 1) waist circumference presents the strongest relationship between metabolic syndrome and C-reactive protein (CRP), an inflammatory indicator; 2) nocturnal oxyhemoglobin desaturation index is the main marker of the relationship between metabolic syndrome and obstructive sleep apnoea ; 3) baroreflex sensibility is largely altered by the metabolic syndrome, in relation with its severity ; 4) the indices of heart rate variability evaluated by 24-hour ECG monitoring, constitute the best marker of autonomic activity decrease with metabolic syndrome ; 5) obesity, evaluated by Body Fat index, a new rnarker created in our laboratory, presents the best association with autonomic activity decrease. Metabolic syndrome is a cluster of interacting factors responsible of, or consecutive to muItiple metabolic dysfunctions. In that view, the combination of these factors worsens the autonomic nervous system deactivation, particularly in women. Our work demonstrates, globally, a strong degree of implication
