Cardiovascular System
One of the first symptoms of stress is an increased heart rate and constricting of blood vessels--which together make a higher blood pressure. For an acute amount of stress, this temporary state is not harmful. However, a chronic amount of stress is detrimental to the cardiovascular system.
The first effect on the heart from chronic stress is hypertension. This increased blood pressure can then wear and tear blood vessels and create lesions in the walls of the arteries, especially where they branch, leading to an inflamatory response in the tears where plaque--immune cells, clumped platelets, and fatty substances like cholesterol-- builds. These changes are known as atherosclerosis, and it makes the blood vessels narrower.
At the narrowed branches of the arteries or where plaque has broken from the artery walls, blood clots can form. Epinephrine increases fibrinogen that makes platelets more likely to stick todgether. This response is designed, in times of acute stress, to reduce the flow of blood from wounds. In chronic stress, this increases the risk of clot formation.
If one of these clots travels to the heart, a heart attack can occur. If one of these clots travels to the brain, it can cut off blood and oxygen supply to certain areas of the brain, causing the neurons in that area to be injured or die (ischemic stroke). Hypertension can cause blood vessels in the brain to weaken over time and rupture causing a hemorrhagic stroke.
These factors together make up the symptoms of metabolic syndrome (syndrome X) that 1 in 4 to 5 Americans have. People with this syndrome are more likely to have coronary artery disease, stroke, or type 2 diabetes.