What is Blood Pressure – And What is Normal?

What is Blood Pressure – And What is Normal?

Blood pressure is the measure of the force that your heart uses to pump blood around your body. It is the pressure exerted by your blood against the walls of your arteries as it circulates.

Think of your circulatory system like the plumbing in a house: for water to reach the taps, there needs to be a certain amount of pressure in the pipes.

In your body, blood pressure ensures that oxygen and nutrients reach every organ, from your brain to your toes.

What Does Blood Pressure Mean? The Physiology

Your blood pressure is a “vital sign” that reflects the health of your heart and blood vessels. It is determined by two main factors:

1. The amount of blood your heart pumps.

2. The amount of resistance to blood flow in your arteries. (Narrower arteries create higher pressure).

The Cardiac Cycle: Systole vs. Diastole

Your heart doesn’t pump blood in one constant stream; it beats in a rhythmic cycle consisting of two phases:

• Systole (Contraction): This is the “active” phase. Your heart muscle contracts to push blood out into the arteries. This is when the pressure in your system is at its highest.

• Diastole (Relaxation): This is the “resting” phase between beats. Your heart relaxes and fills with blood again. This is when the pressure in your system is at its lowest.

How is Blood Pressure Measured?

Blood pressure is measured in millimeters of mercury (mmHg). When you see your results, they are expressed as two numbers, usually written one above the other (e.g., 120/80 mmHg).

1. Systolic Blood Pressure (The Top Number)

The Systolic value is the higher number. It records the pressure in your arteries specifically when your heart beats. It is the most important number for identifying risk factors like heart disease or stroke in older adults.

2. Diastolic Blood Pressure (The Bottom Number)

The Diastolic value is the lower number. It measures the pressure in your arteries when your heart is resting between beats.

Why Understanding Your BP Reading Matters

Knowing your blood pressure is essential because Hypertension (high blood pressure) usually has no symptoms. If the pressure remains too high for too long, it can:

• Damage the lining of the arteries.

• Cause the heart muscle to thicken and weaken.

• Lead to life-threatening events like heart attacks, strokes, or kidney failure.

What is ‘Normal’ Blood Pressure?

There is no such thing as normal blood pressure.

There is a normal range, usually taken to be approximately 90/60 – 135/85.

What is normal depends on many factors including:

• Age – normal BP rises with age, so:
  • 120/70 can be normal in your 20s-30s
  • 130/80 in 40s-60s
  • 140/90 in 70s+
  • Note ‘pulse pressure’ (difference between systolic and diastolic) also increases as you age
• Gender
• If female – pregnant/not (BP goes down in pregnancy).

Summary

Blood pressure is a dynamic measurement of your cardiovascular health. It changes based on your activity, stress levels, and sleep, but keeping it within a healthy range is the single most important thing you can do for long-term health.