Blood pressure represents the force your circulating blood exerts against the walls of your arteries. This measurement indicates cardiovascular health, reflecting how efficiently your heart pumps blood. Understanding these numbers provides insight into your circulatory system’s function.
Key Components of a Reading
Blood pressure readings are expressed as two numbers, such as 120/80 mm Hg. The top number, systolic blood pressure, measures the pressure in your arteries when your heart beats and contracts, pushing blood out.
The bottom number, diastolic blood pressure, reflects the pressure in your arteries when your heart rests between beats, filling with blood. Both measurements are considered equally important in assessing cardiovascular health.
Interpreting Your Numbers
For most adults, normal blood pressure is less than 120 mm Hg systolic and less than 80 mm Hg diastolic. Maintaining blood pressure within this range is associated with a lower risk of heart disease and stroke.
Elevated blood pressure has a systolic reading between 120 and 129 mm Hg and a diastolic reading of less than 80 mm Hg. While not yet high blood pressure, this category indicates a greater likelihood of developing hypertension. Lifestyle adjustments are often recommended to prevent progression.
Hypertension Stage 1 is diagnosed when systolic pressure consistently ranges from 130 to 139 mm Hg or diastolic pressure is between 80 and 89 mm Hg. This stage suggests a need for lifestyle changes and possibly medication, depending on individual risk factors.
Hypertension Stage 2 has consistent systolic readings of 140 mm Hg or higher, or diastolic readings of 90 mm Hg or higher. Healthcare providers recommend medication and lifestyle modifications to manage blood pressure and reduce health risks.
A hypertensive crisis is a medical emergency when systolic pressure exceeds 180 mm Hg or diastolic pressure is higher than 120 mm Hg. Immediate medical attention is required, especially if accompanied by symptoms such as chest pain, shortness of breath, or changes in vision.
Conversely, hypotension, or low blood pressure, occurs when readings fall below 90/60 mm Hg. While ideal blood pressure can vary, consistently low readings can cause symptoms like dizziness or fainting or indicate underlying health issues.
Methods for Measurement
Blood pressure can be measured in a healthcare setting or at home. In a clinic, a healthcare provider uses an inflatable cuff around the arm. As air is released, a stethoscope is used to listen for sounds, or a digital device detects readings.
For accurate home monitoring, use an upper arm cuff monitor, as these provide more reliable results than wrist devices. Before taking a reading, sit quietly with your back supported and feet flat on the floor for at least five minutes. The arm with the cuff should be supported at heart level, and the cuff placed directly on bare skin, not over clothing. Taking multiple readings, one to two minutes apart, and recording them at the same time each day (e.g., morning and evening) provides a more accurate average.
Factors Influencing Readings
Numerous factors can cause temporary fluctuations in blood pressure readings. Physical activity can impact blood pressure, so resting for several minutes before a measurement is recommended. Stress and anxiety can also elevate readings, sometimes leading to “white coat effect” where blood pressure is higher in a clinical setting.
Consumption of caffeine or alcohol within 30 minutes of a measurement can cause a temporary spike in blood pressure. Smoking tobacco products can immediately raise blood pressure due to nicotine. Other influences include a full bladder and room temperature, as cold can cause blood vessels to contract and elevate readings.