Attention, chocolate lovers: You may not be able to help yourselves. Swiss and British scientists have linked the widespread love of chocolate to a chemical "signature" that may be programmed into our metabolic systems.
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High Blood Pressure
- Overview, Causes, & Risk Factors
- Symptoms & Signs
- Diagnosis & Tests
- Prevention & Expectations
- Treatment & Monitoring
- Attribution
- View All
Overview, Causes, & Risk Factors
Blood pressure is expressed in millimeters of mercury, or mm Hg. High blood pressure is defined as a systolic blood pressure reading greater than 140 mm Hg or a diastolic blood pressure reading greater than 90 mm Hg. The systolic blood pressure is the top number of a blood pressure reading. This shows the maximum pressure in the blood vessels. Pressure is highest as the heart contracts and circulates blood throughout the body. The diastolic blood pressure is the bottom number of a blood pressure reading. It shows the lowest pressure in the blood vessels. Pressure is lowest between heartbeats, when the heart is at rest.
The National Institutes of Health has further defined high blood pressure. These categories are for people 18 years and older who do not take medication for high blood pressure and do not have a short-term serious illness. These categories are as follows.
What is going on in the body?
The heart, blood vessels, brain, and kidneys control blood pressure. Blood pressure is also controlled by the amount of fluid and salt in the body. Certain hormones in the body can affect both blood vessels and body fluids. The force of the contraction of the heart can also affect blood pressure.
In most people who have high blood pressure, the cause is unknown. In this case, high blood pressure is called primary, or essential, hypertension.
What are the causes and risks of the condition?
Ninety to 95% of the time, high blood pressure is labeled as essential hypertension. This means that the cause is unknown. The American Heart Association has identified both controllable and noncontrollable risk factors for high blood pressure.
Uncontrollable risk factors for high blood pressure include age, heredity, and race. In men, high blood pressure occurs most often between 35 and 50 years of age. In women, it generally starts after menopause. An individual is more likely to develop high blood pressure if his or her parents or close relatives have it. Certain races have a higher incidence of high blood pressure. For example, African Americans develop high blood pressure earlier and more often than Caucasians.
Controllable risk factors for high blood pressure include the following:
Secondary high blood pressure is caused by one of the following conditions: