Why Is the Systolic on Your Blood Pressure High?
by Diane Ursu
Blood pressure is taken during every doctor's appointment, emergency-room visit and health screening. It is an indicator of cardiovascular health. Elevated blood pressure can be a sign of something wrong. Stressful situations, exercise and other physically demanding situations can temporarily elevate blood pressure. Chronically high blood pressure is known as hypertension, and can be a sign of a more serious problem. Blood pressure readings consist of two measurements: systolic and diastolic. The systolic reading is always the highest. One must have a basic understanding of the heart and circulation to understand why.
The heart consists of four chambers: two atria and two ventricles. The atria are the top chambers of the heart that receive blood. The ventricles are the bottom chambers and pump blood out of the heart. The right atrium receives blood from the venae cavae. The blood flows into the right ventricle, which pushes the blood out of the heart to the lungs for oxygenation. The left atrium receives the oxygenated blood from the lungs. The blood then flows to the left ventricle, which pushes the blood into the aorta for distribution throughout the body.
The arteries carry oxygenated blood from the heart to the rest of the body. Arteries consist of three layers, with the middle layer consisting of muscle. This muscular middle layer is responsible for helping the heart push blood throughout the body. When the heart contracts, the arterial muscle relaxes to receive blood. When the heart relaxes, the arterial muscle contracts to continue pushing blood throughout the body. It is this contraction and relaxation of the arterial muscle that creates a pulse.
Blood pressure is the amount of pressure exerted on the arterial walls by the circulating blood. It is measured in millimeters of mercury (mmHg). The device used to obtain blood pressure readings is called a sphygmomanometer, which consists of a pressure gauge and a blood pressure cuff. The blood pressure cuff is placed on the arm, just above the elbow and at the level of the heart. The brachial artery is the artery that is measured.
Systolic and Diastolic Pressure
The heart's ventricles contract at the same time. When they contract, the heart pushes blood through the arteries. This is known as systole. Since the blood is actively pushed through the arteries, there is more force on the arterial walls. This creates a higher number for the systolic pressure. Diastole occurs when the ventricles relax and the heart is not pushing blood through the arteries.
Hypertension and Systolic Pressure
Hypertension is chronically high blood pressure. The systolic number is the key indicator of hypertension. Normal blood pressure is 120 and hypertension is 140 and greater. The systolic number is the maximum amount of pressure placed on the arterial walls. This number is important because chronically high blood pressure can lead to other cardiovascular problems, such as plaque buildup and heart failure.