Which Number is More Important in Your Blood Pressure Reading - Systolic or Diastolic?

This article is medically reviewed by Dr Valery Feigin | Professor of Neurology & Epidemiology and Director of NISAN (National Institute for Stroke and Applied Neurosciences), Auckland University of Technology.

When you check your blood pressure, you’ll notice two numbers — one over the other, like 120/80 mmHg. But have you ever wondered which number matters more? The answer isn't as straightforward as you might think, it can actually depend on your age and what you're monitoring for.

Let’s break it down.

What Do the Two Numbers Mean?

• Systolic pressure (the top number) measures the force your heart exerts on the walls of your arteries each time it beats.
• Diastolic pressure (the bottom number) measures the force your heart exerts on the walls of your arteries when it rests between beats.

Both numbers are important. But depending on your health profile and age, one might deserve closer attention.

Why Systolic Pressure Often Matters More

For most adults, systolic blood pressure is the bigger concern. High systolic pressure is a major risk factor for cardiovascular disease, particularly for stroke and in people over the age of 50. As we age, arteries naturally stiffen, causing systolic numbers to rise and that’s closely linked to the risk of heart attacks, strokes, and other complications.

That's why many healthcare guidelines focus primarily on controlling systolic pressure to reduce stroke and overall cardiovascular disease risk.

When Diastolic Pressure Matters

While systolic pressure tends to steal the spotlight, diastolic pressure shouldn't be ignored especially for younger adults. In younger patients (aged under 50), a higher diastolic blood pressure reading may carry more weight and deserve careful management. That’s because studies show elevated diastolic pressure in this age group can be a red flag for long-term cardiovascular risk, even if the systolic number appears normal.

It Depends on What You’re Monitoring

• For older adults (50+): Systolic pressure is typically the key focus.
• For younger adults: Both numbers are important, but a high diastolic reading can raise concern.
• If managing chronic conditions (like kidney disease, diabetes, or heart failure): Both systolic and diastolic need to be closely tracked, since either can complicate management.

Final Takeaway

Rather than focusing on just one number, it’s essential to look at the full picture of your blood pressure readings. Regular monitoring, understanding what your numbers mean, and working with your doctor can help you stay ahead of any potential issues, no matter which number is higher.

Because when it comes to your heart health, every beat and every number matters.