Effects of acute psychological stress on serum lipid levels, hemoconcentration, and blood viscosity

Background: While there is substantial evidence that psychological stress enhances risk for coronary artery disease, the mechanisms underlying such an influence remain unclear. We examined the effects of short-term psychological stress on serum lipid levels, hemoconcentration, fibrinogen level, and plasma viscosity. Methods: Forty-four healthy young adults were randomly assigned to perform a distinctly frustrating cognitive task for 20 minutes (stress condition) or to rest quietly for the same period (control condition). Results: Relative to controls, stressed subjects showed significant increases in blood pressure and heart rate; total, low-density, and high-density lipoprotein cholesterol levels; hematocrit; hemoglobin level; and total protein concentration. Stressed subjects also showed significant reductions in plasma volume and increased plasma viscosity and estimated whole-blood viscosity compared with controls. A similar trend in fibrinogen level was not statistically significant. Individual differences in blood pressure and heart rate response to stress correlated highly with changes in total cholesterol levels and hematocrit. Conclusions: Our investigation provides further evidence that exposure to short-term mental stress elicits hemoconcentration with associated increases in serum lipid concentrations, hemostatic factors, and blood viscosity. (Arch Intern Med. 1995;155:615-620)