Blood Pressure: Understanding Systolic and Diastolic Measurements
What is Blood Pressure?
Before we dive into systolic and diastolic blood pressure, let's quickly understand what blood pressure actually is. It's the force that blood exerts against your artery walls as it flows through your body.
Blood pressure is always measured in millimeters of mercury (mmHg) and is written as two numbers, for example, 120/80 mmHg.
Systolic Blood Pressure
Systolic blood pressure is the higher number in your blood pressure reading, and it represents:
- The pressure in your arteries when your heart contracts (beats)
- The maximum pressure exerted on your arterial walls
- Typically ranges from 90-120 mmHg in healthy adults
When your doctor says "120 over 80," the "120" refers to your systolic pressure. This happens when your heart muscle squeezes, pushing blood out into your circulation.
Diastolic Blood Pressure
Diastolic blood pressure is the lower number in your blood pressure reading, and it represents:
- The pressure in your arteries when your heart relaxes between beats
- The minimum pressure maintained in your arterial system
- Typically ranges from 60-80 mmHg in healthy adults
Think of diastolic pressure as your arteries' "resting pressure" - it's the baseline pressure that's always present in your circulatory system.
Understanding the Relationship
To better understand these terms, imagine a pump (your heart) in action:
- When the pump squeezes (systole) → Higher pressure (systolic)
- When the pump relaxes (diastole) → Lower pressure (diastolic)
Students often confuse which number represents which pressure. Remember: Systolic (higher) always comes first in the reading, followed by diastolic (lower).
