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Blood does not travel in a steady flow through the body. Instead it is propelled through the blood vessels with the force of every heartbeat. Here’s a brief overview of blood pressure.

Every organ and tissue in your body requires a constant supply of blood. This blood supply provides the oxygen and nutrients your body needs to perform its normal functions and to dispose of the waste products that result from these functions.

To meet these needs, the heart has to pump blood through about 60,000 miles of blood vessels that wind their way to and from even the most distant tissues from the heart. This blood-vessel maze is more than twice the earth’s circumference. To navigate it, a certain amount of force is required to propel blood through the body and return it to the heart. Blood pressure is that force.

Your body generates blood pressure in two main ways:

  1. Blood flowing through the arteries (vessels that carry blood from the heart to the tissues) creates pressure. The more blood the heart pumps with each heartbeat, the greater the amount of blood flowing through the arteries, and thus the greater the pressure against the artery walls.
  2.  

  3. The arteries themselves create pressure by resisting blood flow. Small arteries contain smooth muscle cells, which contract and expand like any other muscle in your body. When these muscles contract, the opening in the artery becomes smaller, and the pressure inside the artery increases as blood flows through.

The amount of pressure required to circulate blood varies according to your body’s needs. For example, your body requires less blood when you’re sitting still or sleeping than when you’re exercising or doing strenuous work. A complex mix of hormones and nerves regulates blood flow in response to your body’s changing needs.

In many people, this regulatory system goes awry and blood pressure remains persistently high, even at rest, resulting in a condition called high blood pressure, or hypertension. High blood pressure is one of the most important risk factors for stroke and heart attack.

Cardiac Risk From Chronic Stress

By Rick Nauert PhD Senior News Editor
Reviewed by John M. Grohol, Psy.D. on January 25, 2010

Tulane University researchers believe chronic stress following Hurricane Katrina contributed to a three-fold increase in heart attacks in New Orleans more than two years after the event.

Those suffering heart attacks post-Katrina also were significantly more likely to receive coronary interventions, particularly angioplasty to reopen clogged coronary arteries, which suggests these patients may have more severe disease.

The analysis is one of the first to look at the long-term impact on public health resulting from major disasters such as Hurricane Katrina.

Previous studies have found short-term increases in heart attacks and other cardiac events occurring in the immediate hours to weeks after major disasters such as earthquakes or volcano eruptions.

“Our data show that the effects of an acute major disaster are not limited to its immediate aftermath, but can linger on for a prolonged duration,” said lead researcher Dr. Anand Irimpen, associate professor of clinical medicine at Tulane University School of Medicine.

The study analyzed the number of heart attack patients admitted to Tulane Medical Center in downtown New Orleans two years before the storm and two years after the hospital reopened in February 2006.

Researchers compared the two groups (pre- and post-Katrina) based on specific demographic and clinical data such as lab test results, health insurance, first-time hospitalization, smoking status, substance abuse and employment.

There were 246 admissions for heart attacks, out of a total census of 11,282 patients, post-Katrina compared with 150 admissions out of a total 21,229 patients in the two years before the storm.

In addition to a three-fold increase in heart attacks and a 120 percent increase in coronary interventions, the post-Katrina group had significantly higher prevalence of unemployment, lack of medical insurance, medication noncompliance, smoking, substance abuse, first-time hospitalization and people living in temporary housing.

There were no significant differences in the racial, gender or age distribution of the two groups.

Based on these data, the authors believe reduced access to preventive health services and chronic stress due to prolonged loss of employment, insurance coverage and housing played an important role in the development of heart attacks.

In addition, it appears chronic stress following Katrina may have fostered bad health practices, such as smoking and failure or refusal to adhere to treatment plans. “After a major disaster, people generally tend to neglect their health because they have other priorities,” Irimpen said.

“That can lead to serious consequences.”

Irimpen said that further study is needed into the long-term affects of chronic stress and his team will track the rates of heart attacks for another two years. They also will include other area hospitals in the study.

Source: Tulane University

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