Plaisance EP et al. - Aerobic exercise lowers the postprandial triglyceride response to a high-fat meal. Niacin lowers fasting but not postprandial triglycerides and appears to influence the triglyceride-lowering effect of aerobic exercise when combined. However, exercise decreases postprandial insulin concentrations after niacin administration, which illustrates the potential metabolic benefits of exercise in persons taking niacin.