Blood pressure describes the force of the blood against the walls of the blood vessels. Doctors measure blood pressure as a combination of two numbers; the systolic pressure measures the pressure inside the blood vessels as the heart beats, and the diastolic pressure, measures the pressure as the heart relaxes between beats. The two numbers are written like a fraction: the systolic on top and the diastolic on the bottom. Although many factors affect blood pressure, including activity, temperature, emotional state, posture and medications, it helps to indicate the overall health of the body.
High Blood Pressure Readings
In normal healthy individuals, blood pressure remains below a systolic reading of 120 mm Hg and a diastolic reading of less than 80 mm Hg. As blood pressure rises overall health can be affected. Doctors classify a systolic pressure between 120 and 139 mm Hg with a diastolic pressure ranging from 80 to 89 mm Hg as prehypertension, a condition that requires careful monitoring in order to avoid additional health complications. High blood pressure, a condition known as hypertension, occurs when the blood pressure readings rise above 140 mm Hg over 90 mm Hg, according to the American Heart Association.
Effects on the Blood Vessels
High blood pressure affects the blood vessels throughout the body. Healthy blood vessels are flexible and elastic. The increased pressure against the walls of the vessels causes the vessels to become thick and stiff, therefore, restricting the flow of blood, a condition known as arteriosclerosis. Damage to the walls of blood vessels attracts platelets and other substances in the blood such as fats, cholesterol and calcium. The accumulation of these substances, known as atherosclerosis, restricts blood flow and contributes to the development of heart disease.
Effects on the Heart
High blood pressure causes the heart to work harder in order to pump blood. The heart is a muscle, and as it works harder, it thickens and enlarges. And as the walls of the heart thicken, it becomes increasingly difficult for it to pump, which can lead to congestive heart failure---a condition in which the heart fails to pump enough blood to meet the needs of the body. This can result in the common symptoms of shortness of breath and fatigue.
Effects on the Kidneys
The kidneys filter waste products and excess fluid from the blood and expel it as urine. Each kidney contains millions of tiny blood vessels. When high blood pressure damages the blood vessels in the kidneys, they fail to filter blood effectively. This allows excess fluid and salts to remain in the blood, therefore, increasing blood volume. The increased volume of blood increases blood pressure further, and increases the workload of both the heart and kidneys, contributing to heart disease and kidney damage.
Physical Symptoms
High blood pressure affects approximately one in three American adults, according to the University of Maryland Medical Center. Even though high blood pressure affects the blood vessels and internal organs, most patients fail to exhibit any physical symptoms. Therefore, many refer to high blood pressure as the "silent killer". High blood pressure can, however, cause frequent dull headaches, dizzy spells and nosebleeds.
