This response can be unhealthy when it occurs frequently and continuously in long term stressful situations. However, if we alter our perception, we can change the experience of stress and moderate our reaction. Many medical conditions are caused by or made worse by stress. These include hypertension and coronary artery disease. The fight or flight response stimulates the nervous system to release stress hormones, which affect the heart and blood vessels directly by making the heart beat faster, increasing the breathing rate, and increasing blood pressure.
Stress causes the blood vessels, including the coronary arteries, to constrict, or tighten.
Stress also causes the blood to clot more easily. With chronic stress, the blood vessels can become injured then become thickened and damaged, making them more vulnerable to atherosclerotic plaque formation. Stress Hardiness Researchers have shown that some individuals are less vulnerable to stress or seem to have a resistance to stress. They are stress hardy. It is our daily hassles that are the primary underlying sources of stress.