Aim 1: determine whether acute exposure to stress (increasing sympathetic nervous system activation) increases plasma amyloid-beta-40 and amyloid-beta-42 in the five hours following exposure.
Research has shown that activation of the sympathetic nervous system for extended periods or during certain times in life can increase the risk for Alzheimer's disease. Some research in animal models show that acute activation of the sympathetic nervous system through stress exposure can increase certain Alzheimer's disease-related biomarkers, such as amyloid-beta, within hours of exposure. However, how acute sympathetic nervous system activation via stress exposure affects amyloid-beta levels in humans has yet to be examined.~In this study, the investigators will examine whether brief increases in sympathetic activation result in immediate changes in plasma amyloid-beta levels in the five hours after exposure.