The inner lining of blood vessels, called the endothelium, controls blood flow, clot prevention, and vessel flexibility. Chronic stress exposes this lining to repeated surges of stress hormones and inflammatory signals. These chemicals were designed for short emergencies, not constant exposure. Over time, stress hormones increase oxidative damage and reduce nitric oxide production, a substance essential for vessel relaxation. The endothelial surface becomes less smooth and less responsive. This