First, let's explore what blood pressure means. It appears as two numbers. The first, called systolic pressure, tells you the force when your heart beats. The second, called diastolic pressure, shows the force when your heart rests between beats.
Typically, a reading of 120/80 mmHg signals healthy pressure. Keeping your blood pressure normal reduces your risk of heart disease, stroke, and kidney problems.
Understanding the Numbers
Systolic Pressure (Top Number)
The systolic number represents the maximum pressure in your arteries. This occurs during the moment your heart contracts (beats) and pushes blood out into your body. It's the higher of the two numbers because this is when pressure is at its peak.
Diastolic Pressure (Bottom Number)
The diastolic number represents the minimum pressure in your arteries. This occurs when your heart relaxes between beats and refills with blood. It's always the lower number because pressure drops when the heart isn't actively pumping.
Blood Pressure Categories
| Category | Systolic | Diastolic |
|---|---|---|
| Normal | Less than 120 mmHg | Less than 80 mmHg |
| Elevated | 120-129 mmHg | Less than 80 mmHg |
| High BP Stage 1 | 130-139 mmHg | 80-89 mmHg |
| High BP Stage 2 | 140+ mmHg | 90+ mmHg |
| Hypertensive Crisis | 180+ mmHg | 120+ mmHg |
Hypertensive Crisis
How Measurement Works
Blood pressure is measured using a device called a sphygmomanometer—though you probably know it as a blood pressure monitor or BP cuff. Here's what happens during a measurement:
- The cuff inflates: An inflatable cuff wraps around your upper arm and inflates, temporarily stopping blood flow through the brachial artery.
- The cuff slowly deflates: As air releases from the cuff, blood begins to flow again. The monitor detects this change.
- Systolic reading captured: The first sounds of blood flow (detected by sensor or stethoscope) indicate your systolic pressure.
- Diastolic reading captured: When the sounds disappear (blood flowing freely), this indicates your diastolic pressure.
Tips for Accurate Measurements
Getting accurate readings at home requires proper technique. Even small errors can lead to readings that are off by 10 mmHg or more.
Before Measuring
- Avoid caffeine, exercise, and smoking for 30 minutes before
- Empty your bladder
- Sit quietly for 5 minutes before taking a reading
- Don't measure when stressed or after a stressful event
During Measurement
- Sit with your back supported and feet flat on the floor
- Place your arm on a flat surface at heart level
- Position the cuff on bare skin, not over clothing
- Keep still and don't talk during the measurement
After Measuring
- Take 2-3 readings, one minute apart
- Record all readings along with the date and time
- Calculate the average of multiple readings
- Note any factors that might have affected the reading
Why Tracking Matters
A single blood pressure reading is just a snapshot. Your blood pressure naturally fluctuates throughout the day based on activity, stress, food, and other factors. That's why tracking multiple readings over time gives you—and your doctor—a much clearer picture of your cardiovascular health.
Regular tracking helps you:
- Identify patterns and trends
- Understand how lifestyle factors affect your BP
- Monitor the effectiveness of medications
- Catch problems early, before they become serious
- Have meaningful conversations with your healthcare provider
