The Arterial System
The Arterial System consists of the heart and the body's arteries. Arteries are blood vessels that take blood away from the heart. Veins are blood vessels that return blood to the heart. Capillaries are smaller blood vessels that assist the arteries in transporting the oxygen rich blood to the outer areas of the body. The heart functions as the pump that pushes the blood through the blood vessels. In order for the human body to function properly, it must receive a constant supply of blood.
Normally, the artery walls expand to allow blood to flow through easily. This helps to maintain normal blood pressure.
Measuring Blood Pressure
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. Your doctor may take several readings over a period of time before making a judgment about whether or not your blood pressure is considered to be in a high level range.
As blood is pumped through your body it exerts a force against the blood vessels. The amount of blood the heart pumps and the resistance of the arteries determines your blood pressure. Blood pressure is recorded as two numbers, a top number and a bottom number. The top number is your systolic number. This represents the pressure while the heart is beating. The bottom number is your diastolic pressure, or the blood pressure when the heart is at rest between beats.
The systolic pressure is always stated first and the diastolic pressure second. For example: 122/76 (122 over 76); systolic = 122, diastolic = 76.
Normal vs. High Blood Pressure
Normal blood pressure is below 120/80. To get an accurate reading, blood pressure should be taken several times during the day to find an average blood pressure. Blood pressure readings 120-139/80-89 are considered "prehypertensive" and are considered at increased risk for high blood pressure. High blood pressure is any reading that is equal to or over 140/90. If your blood pressure is above that reading, you may have high blood pressure, or hypertension.
Many people have high blood pressure for years without knowing it. Uncontrolled high blood pressure can lead to stroke, heart attack, heart failure or kidney damage. According to recent statistics, one in three U.S. adults has high blood pressure, but because there are no symptoms, nearly one-third of these people don't even know that they have it.
High blood pressure can hurt your body in many ways especially by increasing to the workload of your heart and arteries. Because your heart must work harder than normal for a long time, it tends to get bigger. A slightly bigger heart may work well, but if it's enlarged too much, it may have a hard time meeting your body's demands.
High blood pressure is the No. 1 modifiable risk factor for a stroke. It may also contribute to heart attacks, kidney failure and atherosclerosis. In some cases, it can cause blindness. Compared to people with controlled high blood pressure, people with uncontrolled high blood pressure are:
- Three times more likely to develop coronary heart disease
- Six times more likely to develop congestive heart failure
- Seven times more likely to have a stroke
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, medically known as atherosclerosis.
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 of the oxygen and nutrients the blood delivers, they can't work properly. Another risk is that a blood clot may lodge in an artery narrowed by atherosclerosis, depriving part of the body of its normal blood supply.
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 through physician prescribed lifestyle modifications, drug therapies and routine physician follow up. And, its effects can be prevented or reduced - if it's treated and controlled early, and kept under control.
Blood Vessels and High Blood Pressure
Blood flows through easily in a normal artery. The white arrows represent blood pressure.
When you have high blood pressure, the blood vessels become tight and constricted, forcing the heart to pump harder to move blood through. These changes cause the blood to press on the vessel walls with great force.
Over time, fatty deposits may build up along the walls and cause hardening of the arteries. The heart must work even harder to pump blood through these hardened arteries.
Risk Factors that Affect Blood Pressure
If you are an adult and your normal blood pressure level is 140/90 mm Hg or above, you could be at risk for heart disease, stroke and other medical problems. See a doctor and get recommendations on how to manage your blood pressure and how often to have it checked. Remember, high blood pressure has no symptoms, so if you haven't had it checked in a while, make an appointment now. One in four adult Americans has high blood pressure, and nearly one-third of them don't know they have it.
Factors that contribute to high blood pressure
Because medical science doesn't understand why most cases of high blood pressure occur, it's hard to say how to prevent it. However, we do know of several factors that may contribute to high blood pressure and put you at risk for a heart attack and/or stroke.
Controllable risk factors
- Obesity - People with a body mass index (BMI) of 30.0 or higher are more likely to develop high blood pressure.
- Smoking - If you smoke, ask your healthcare professional or doctor about a program to help you quit.
- Eating too much salt - This increases blood pressure in some people.
- Alcohol - Heavy and regular use of alcohol can increase blood pressure dramatically.
- Lack of exercise - 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. However, stress levels are hard to measure, and responses to stress vary from person to person. However, it is always best to try to eliminate as much stress from your life as possible.
Uncontrollable risk factors
- Race - African Americans have a higher occurrence of high blood pressure than other ethnicities. High blood pressure also tends to occur earlier and be more severe in African Americans.
- Heredity - A tendency to have high blood pressure runs in families. If your parents or other close blood relatives have it, 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 50. Women are more likely to develop it after menopause.
- Sex - In general, males have a greater chance of developing high blood pressure.
Controlling Blood Pressure
High blood pressure is a lifelong disease. It can be controlled but not cured. Once you begin to manage it and start a treatment program, maintaining a lower blood pressure is easier. By controlling your high blood pressure, you'll lower your risk for diseases and conditions such as kidney disease, stroke, heart attack, or heart failure.
- High blood pressure can be controlled through a variety of healthy lifestyle changes. A lot can be done to reduce high blood pressure.
- Maintain a healthy weight for your age.
- Reduce your salt intake and cut down on products high in sodium.
- Exercise regularly. Check with your doctor before starting any exercise program.
- Learn to manage your stress. Check with your doctor about stress management techniques that can work for you.
- Take your blood pressure medication according to your doctor's instructions.
- Have your blood pressure checked regularly.