2 BLOOD PRESSURE 2 BLOOD PRESSURE CHAPTER ONE We can’t see it, touch it, hear it, smell it, or taste it. That makes blood pressure easy to ignore. But we can measure blood pressure, and it’s not looking good. The Centers for Disease Control and Prevention estimate that 90 percent of middle-aged American adults will eventually suffer from hypertension. And because blood pressure is so easy to ignore, almost 30 percent of people with hypertension are blissfully unaware of their own condition. High blood pressure—measured at 140 mmHg over 80 mmHg or higher—is aptly called “the silent killer.” It can lead to stroke, enlarged heart, congestive heart failure, kidney and eye damage, atherosclerosis (hardening of the arteries), mental decline, and early death. In fact, in 2002, hypertension was cited as a leading or contributing factor in 277,000 American deaths. RISK FACTORS FOR HYPERTENSION There are some risk factors we can’t do anything about like our age, race, or gender. But we can control many of the other risk factors for hypertension, such as obesity, poor diet and lifestyle choices, and lack of proper medical care. DEFINING BLOOD PRESSURE Blood pressure is the force of the bloodstream against the walls of the arteries as they send blood from the heart to the rest of the body. At the end of each artery, tiny blood vessels called arterioles deliver blood to all the tissues. When the walls of the arterioles tighten, blood pressure goes up. When those walls relax, blood pressure goes down. What do those blood pressure numbers mean? The higher number refers to systolic blood pressure, which is the pressure exerted when the heart contracts. The lower number, the diastolic pressure, measures the rests between heartbeats. Most hypertensive Americans have “essential hypertension,” a form of high blood pressure with no clear cause. Rarely, high blood pressure is caused by underlying health issues such as kidney disease or congenital problems.We call this “secondary hypertension.”“Gestational hypertension” may occur during pregnancy, and is implicated in low birth weight and early delivery.