The terms diastole and systole refer to when the heart muscles relax and contract. The balance between diastole and systole determines a person’s blood pressure. The heart is a pump that supplies all tissues and organs of the body with oxygen-rich blood. The heartbeat is caused by the heart muscles relaxing and contracting. During this cycle, the period of relaxation is called diastole and the period of contraction is called systole. In this article, we will explain how diastole and systole relate to blood pressure. We also discuss what is normal blood pressure, along with risk factors and complications linked to high blood pressure (hypertension) and low blood pressure (hypotension). Share on PinterestDiastole is when the heart muscle relaxes and systole is when the heart muscle contracts. Diastole is defined by the following characteristics:
Systole is defined by the following characteristics:
The heart is a pump composed of four chambers. It is divided in the middle into a right and left side, and each side is divided further into two chambers — the upper and lower chambers. The two upper chambers of the heart called the atria receive the blood that is entering the heart. The two lower chambers are called the ventricles. They pump the blood out of the heart to the rest of the body. To pump the blood around the body, the heart contracts and then relaxes over and over again in a cycle called the cardiac cycle. The cycle begins when the two atria contract, which pushes blood into the ventricles. Then, the ventricles contract, which forces the blood out of the heart. The deoxygenated blood that comes back from the body to the right side of the heart is then pumped through the lungs where it picks up oxygen. The oxygenated blood then travels to the left side of the heart and is pumped to the rest of the body. Diastole and systole affect a person’s blood pressure differently, as follows:
When a person receives their blood pressure results, they will see two numbers that represent the diastole and systole measurements. These measurements are given as millimeters of mercury (mm Hg). The first number is the systolic pressure and the second is the diastolic pressure. According to the American College of Cardiology’s (ACC) updated 2017 guidelines, the current blood pressure categories are:
These updated guidelines are likely to place 46 percent of Americans in the category of having high blood pressure. Blood pressure is always measured when the person is at rest and over several days. Its measurements are also called blood pressure readings. A person’s blood pressure can become too high or too low for many reasons. Both high and low blood pressure can cause serious health consequences if left untreated. High blood pressureShare on PinterestGender and age may increase a person’s risk of high blood pressure.High blood pressure or hypertension is when a person has abnormally high pressure against the walls of their blood vessels. This condition develops gradually over many years and may go unnoticed for a long time, as there are often no symptoms. The following risk factors increase a person’s risk of high blood pressure:
When left untreated, high blood pressure can cause complications and, eventually, serious health problems, such as:
Low blood pressureLow blood pressure or hypotension occurs when a person has abnormally low blood pressure against the walls of their blood vessels. Risk factors that increase a person’s chance of developing the condition include:
A person with mild low blood pressure may experience fatigue, fainting, or dizziness. More severe forms of low blood pressure can compromise oxygen-rich blood flow to the body’s major organs, including the brain. If this happens, a person may feel sleepy, confused, or light-headed. In serious cases, this can evolve to heart or brain damage. Diastole and systole are two phases of the cardiac cycle. They occur as the heart beats, pumping blood through a system of blood vessels that carry blood to every part of the body. Systole occurs when the heart contracts to pump blood out, and diastole occurs when the heart relaxes after contraction. A person who suspects that they have high or low blood pressure should consult their doctor to find out the best treatments, which may include medications or lifestyle changes. Even if a person is taking medication for problematic blood pressure, they should still measure their blood pressure levels regularly, since the condition may not have any apparent symptoms. |