REDUCING YOUR RISK OF CORONARY ARTERY DISEASE: HIGH BLOOD PRESSURE – WHAT CAUSES HIGH BLOOD PRESSURE?
Although increased output from the heart, such as occurs normally with exercise, may elevate blood pressure, the usual cause of abnormally high blood pressure is a persistent increase in resistance to blood flow through the small arterioles (the smaller branches in arteries). The arterioles can be compared to a hose.It takes less pressure to push water through a hose with a large diameter than through a narrower hose.The cause of the abnormal increase in resistance in the arterioles remains unknown in 95 percent of people, and they are said to have primary, or essential, hypertension. Hypertension runs in some families, although the problem may never develop in many relatives. Men and women are equallyaffected. For women who take birth control pills and smoke cigarettes, the risk of developing high blood pressure increases. High blood pressure is more common in blacks than in whites. Everyone’s risk increases with age. Additional factors that promote the development of high blood pressure include lack of exercise, excess weight, and alcohol use. A high intake of sodium in the diet increases blood pressure in some people.About 5 percent of people have high blood pressure caused by some other problem in the body (secondary hypertension). Blockage of the arteries leading to the kidneys or excess production of hormones normally involved in blood pressure control are uncommon causes of high blood pressure. Your doctor may want to determine whether one of these unusual disorders is the cause of your high blood pressure so that it can be corrected.*257\252\8*