Hemodynamics of the male fat distribution pattern.

A male fat distribution pattern with abdominal obesity increases the risk for hypertension and cardiovascular disease, and is closely linked to a number of metabolic aberrations including insulin resistance. Recent observations suggest that changes in the peripheral vasculature may be of pathophysiological importance for the development of hypertension and its associated metabolic disturbances. We therefore investigated the hemodynamic correlates of abdominal obesity. A central fat distribution was found to be associated with a specific hemodynamic profile, characterized by elevated total peripheral resistance and lower cardiac output. In response to sympathoadrenal activation during mental stress, the normal cardiac output-dependent pressor response was reversed into a systemic vasoconstrictor response. There was a direct relationship between degree of abdominal obesity (expressed as waist-hip ratio) and fasting serum insulin. Furthermore, the stress-induced increase in total peripheral resistance correlated positively with fasting serum insulin concentration, whereas there was an inverse relation between serum insulin and cardiac output and heart rate. In a second study, the circulatory responses to stress during physiological hyperinsulinemia were investigated. During hyperglycemic hyperinsulinemia the central hemodynamic response to stress was changed into a systemic vasoconstrictor response. In the forearm the physiological vasodilation during stress was markedly attenuated, suggesting that insulin may have peripheral vascular effects. In conclusion, central obesity is associated with a specific hemodynamic pattern characterized by higher total peripheral resistance and lower cardiac output, and a vasoconstrictor response to psychosocial stress. This hemodynamic response pattern may be related to insulin metabolism.