Blood pressure measures the force of blood against artery walls as it circulates. This reading includes two numbers: systolic blood pressure (SBP) and diastolic blood pressure (DBP). Understanding both values provides insight into cardiovascular health.
Defining Systolic and Diastolic Blood Pressure
Systolic blood pressure, the upper number, measures the pressure in your arteries when your heart beats. This phase, known as systole, occurs as the heart’s ventricles contract, pushing blood into the aorta and major arteries.
Diastolic blood pressure, the lower number, measures the pressure in your arteries when your heart rests between beats. During this relaxation phase, called diastole, the heart fills with blood in preparation for the next contraction. Both numbers provide distinct information about the forces within your circulatory system during different phases of the cardiac cycle.
Interpreting Blood Pressure Readings
Blood pressure readings are categorized to assess cardiovascular health. A normal blood pressure reading is less than 120 millimeters of mercury (mmHg) systolic and less than 80 mmHg diastolic. For example, a reading of 110/70 mmHg would fall within the normal range.
When systolic pressure is between 120 and 129 mmHg and diastolic pressure is less than 80 mmHg, it is classified as elevated blood pressure. This indicates an increased risk of developing high blood pressure if lifestyle changes are not adopted. Stage 1 hypertension is diagnosed when systolic pressure is between 130 and 139 mmHg or diastolic pressure is between 80 and 89 mmHg.
Stage 2 hypertension is defined by a systolic pressure of 140 mmHg or higher, or a diastolic pressure of 90 mmHg or higher. A hypertensive crisis occurs when blood pressure rises above 180 mmHg systolic and/or 120 mmHg diastolic, requiring immediate medical attention. Low blood pressure, or hypotension, is defined as a reading below 90/60 mmHg and can cause symptoms like dizziness or fainting.
Factors Affecting Blood Pressure
Many factors can influence blood pressure readings. Lifestyle habits play a significant role, including dietary choices. Consuming foods high in sodium and low in potassium can increase blood pressure, while a diet rich in fruits, vegetables, and whole grains can help manage it.
Physical activity levels also impact blood pressure. A lack of regular exercise can contribute to higher readings, whereas consistent physical activity can help lower blood pressure. Other lifestyle elements like excessive alcohol consumption, tobacco use, and insufficient sleep can also elevate blood pressure.
Beyond lifestyle, non-modifiable factors like age and genetics play a part. As individuals age, their systolic blood pressure increases due to stiffer arteries and plaque buildup. A family history of high blood pressure also suggests an increased predisposition. Underlying medical conditions such as chronic kidney disease, thyroid problems, obstructive sleep apnea, and obesity can contribute to elevated blood pressure.