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.

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.

Inclusion Criteria:

• Healthy adult weighing at least 110 pounds
• No chronic conditions or illness
• Taking no medications or drugs that might alter the stress response (e.g., corticosteroids, beta-blockers, and others)
• Not using any hormone-containing medication (e.g., hormonal contraceptives, hormone replacement, etc.)
• No contraindications for cold pressor test exposure (high blood pressure, heart disease, dysrhythmia, peripheral vascular disease, any other cardiovascular disorder, diabetes, vasculitis, lupus, tingling or numbness in the hands and/or feet, cryoglobulinemia, and Reynaud's phenomenon)
• No history of fainting during blood draws
• No phobia of having their blood drawn
• No general history of fainting or seizures
• Not currently diagnosed with a mood disorder (e.g., major depressive disorder)
• Not pregnant in the past 12 months
• Not lactating in the past 12 months
• Not trying to become pregnant if premenopausal
• Experienced natural menopause if postmenopausal
• Be non-smokers
• Be fluent in English

Exclusion Criteria:

- Unwilling to be filmed during the stress task OR unwilling to sign the waiver allowing their filmed responses to be used in scientific presentations

Anonymized data (values of outcome measures and associated experimental conditions) will be shared publicly on Open Science Framework.

Data will be made available by publication of the paper reporting on the results.

Publicly available.