What does blood pressure really mean?

People hear so much about blood pressure and how keeping it in check is vital for their health, but how many really know what the numbers mean?

A survey completed by the National Institutes of Health revealed that a significant number of people don’t have a complete understanding of their blood pressure reading and its critical impact on their health.

Here are some facts from the the American Heart Association:

What does it mean?
Essentially blood pressure is a ratio describing the force of blood pushing against the walls of the arteries as the heart pumps blood.

The top number: Represents the Systolic measurement, or the pressure in the arteries when the heart beats (when the heart muscle contracts). This should be the higher number. This measurement typically receives more attention as a major risk factor for cardiovascular disease for people 50 years old and older. In most people, systolic blood pressure rises steadily with age due to increasing stiffness of large arteries, long-term build-up of plaque, and increased incidence of cardiac and vascular disease.

The bottom number: Represents the Diastolic measurement, or pressure in the arteries between heartbeats (when the heart muscle is resting between beats and refilling with blood). This is the lower of the two numbers.

To understand the negative impacts of high blood pressure (HPB), people must first understand how blood pressure allows the body to function. It starts with oxygen, which is needed by organs to survive. Blood carries and distributes oxygen throughout the body. As the heart beats, it creates a pressure to pump blood through a network of arteries.

“As blood pressure rises, the strain on the arteries increases and causes them over stretch,” says Dr. Irina Staicu, cardiologist with Advocate Heart Institute at Advocate Good Shepherd Hospital in Barrington, Ill. “Over time, this constant force damages the walls of the arteries and creates several problems.”

A few of these problems include:

• Vascular weaknesses: Overstretching that creates weak places in the blood vessels, making them more prone to rupture. This can lead to hemorrhagic strokes and aneurysms.
• Vascular scarring: Overstretching that can cause tiny tears in the blood vessels that leave scar tissue on the walls of arteries and veins. These tears and the scar tissue act as nets and can catch cholesterol blood cells traveling in the bloodstream causing build-up.
• Blockage: This can occur when trapped blood forms clots or cholesterol and plaque create a buildup. As this happens, pressure is increased on the rest of the system, forcing the heart to work harder to deliver blood to your body. Additionally, if pieces of plaque break off and travel to other parts of the body, or if the build-up completely blocks the vessel, then heart attacks and strokes occur.

“The most difficult thing about treating high blood pressure is that many times the patient has no idea it is occurring,” says Dr. Staicu. “There are no confirmed symptoms to warn you until it becomes deadly. Without symptoms, regularly measuring and understanding your blood pressure can save your life.”

What exactly causes blood pressure to rise? Even the experts don’t have a confident answer.

The American Heart Association claims that an estimated 90 percent of HPB cases have unknown causes. However, several factors that can increase your risk of developing HPB have been identified:

• Family History of HBP
• Advanced age
• Lack of physical activity
• Poor diet, especially one that includes too much salt
• Overweight and obesity
• Drinking too much alcohol

In addition, secondary hypertension can occur when blood pressure rises due to a pre-existing problem. Common problems include kidney abnormalities, structural abnormality, and narrowing of certain arteries. Fortunately, such problems can normally be fixed before HBP becomes serious.

“The keys to avoiding the long term effects of high blood pressure are maintaining a healthy lifestyle and having it regularly checked,” says Dr. Staicu.

Do you know your risk for heart disease? Take our heart risk assessment here. If you are at high risk, see one of Advocate Heart Institute’s cardiologists within 24 hours.