High Blood Pressure
Everybody has — and needs — blood pressure. Without it, blood can't circulate through the body. And without circulating blood, vital organs can't get the oxygen and food that they need to work. So it's important to know about blood pressure and how to keep it within a healthy level. Normal blood pressure falls within a range; it's not one set of numbers.
When the heart beats, it pumps blood to the arteries and creates pressure in them. This pressure (blood pressure) results from two forces. The first force is created as blood pumps into the arteries and through the circulatory system. The second is created as the arteries resist the blood flow.
If you're healthy, your arteries are muscular and elastic. They stretch when your heart pumps blood through them. How much they stretch depends on how much force the blood exerts.
Your heart beats about 60 to 80 times a minute under normal conditions. Your blood pressure rises with each heartbeat and falls when your heart relaxes between beats. Your blood pressure can change from minute to minute, with changes in posture, exercise or sleeping, but it should normally be less than 120/80 mm Hg (millimeters of mercury) for an adult. Blood pressure that stays between 120–139/80–89 is considered prehypertension and above this level (140/90 mm Hg or higher) is considered high (hypertension). Your doctor may take several readings over time before deciding whether your blood pressure is high.
What do blood pressure numbers indicate?
The higher (systolic) number represents the pressure when the heart is beating.
The lower (diastolic) number represents the pressure when the heart is resting between beats.
The systolic pressure is always stated first and the diastolic pressure second. For example: 118/76 (118 over 76); systolic = 118, diastolic = 76.
Controllable risk factors
Obesity — People with a body mass index (BMI) of 30.0 or higher are more likely to develop high blood pressure.
Eating too much salt — A high sodium intake increases blood pressure in some people.
Drinking too much alcohol — Heavy and regular use of alcohol can increase blood pressure dramatically.
Lack of physical activity — An inactive lifestyle makes it easier to become overweight and increases the chance of high blood pressure.
Stress — This is often mentioned as a risk factor, but stress levels are hard to measure, and responses to stress vary from person to person.
Uncontrollable risk factors
Race — Blacks develop high blood pressure more often than whites, and it tends to occur earlier and be more severe.
Heredity — If your parents or other close blood relatives have high blood pressure, you're more likely to develop it.
Age — In general, the older you get, the greater your chance of developing high blood pressure. It occurs most often in people over age 35. Men seem to develop it most often between age 35 and 55. Women are more likely to develop it after menopause.
High blood pressure can hurt your body in many ways. It adds to the workload of your heart and arteries. Because your heart works harder than normal for a long time, it tends to get bigger. A slightly bigger heart may work well, but if it's enlarged very much, it may have a hard time meeting your body's demands.
High blood pressure is the No. 1 modifiable risk factor for stroke. It also contributes to heart attacks, heart failure, kidney failure and atherosclerosis (fatty buildups in arteries). In some cases, it can cause blindness. The relationship of blood pressure levels to the risk of cardiovascular disease is continuous, consistent and independent of other risk factors. That means the higher your blood pressure, the greater your risk of heart attack, heart failure, stroke and kidney disease.
Arteries and arterioles (small arteries) also suffer the effects of higher blood pressure. As you grow older, your arteries will harden and become less elastic. This occurs gradually in all people, even if they don't have high blood pressure. But having high blood pressure tends to speed up this process.
Arterial damage is bad because hardened or narrowed arteries may not be able to supply the amount of blood the body’s organs need. And if the body's organs don't get enough blood (and the oxygen and nutrients it delivers), they can't work properly. Another risk is that a blood clot may lodge in an artery narrowed by fatty deposits, depriving part of the body of its normal blood supply.
The good news is, blood pressure is easily controllable through lifestyle changes — eating heart-healthy diet, limiting alcohol, avoiding tobacco smoke, controlling your weight and getting regular physical activity — and medication, if your doctor recommends. If you have high blood pressure, follow your doctor's advice. Most high blood pressure can't be cured, but it usually can be controlled. And its effects can be prevented or reduced — if it's treated and controlled early, and kept under control.