Two Tests, Two Very Different Purposes

A stress test and a heart scan both relate to heart health, but they measure completely different things. A stress test looks at how well your heart performs while you’re exercising, essentially checking how your heart functions under physical pressure. A heart scan, on the other hand, is designed to look inside your coronary arteries to detect calcified plaque buildup long before symptoms appear.

Because these two tests measure different aspects of heart health, it’s absolutely possible for someone to have a perfect stress test but still have significant plaque that only a CT calcium scoring scan can reveal.

What a Stress Test Measures

A stress test focuses on performance. It evaluates:

• How your heart responds to movement and exertion
• Whether exercise triggers chest discomfort
• Your blood pressure and heart rhythm during activity
• Signs of reduced blood flow during stress
  
  

This test identifies problems that show up when the heart is working harder. But it does not show hidden plaque inside the arteries. Many people with early or moderate plaque pass a stress test because the blockage has not grown enough to reduce blood flow during exercise.

What a Heart Scan Measures

A heart scan (coronary calcium scoring CT) looks at structure, not performance. It images:

• Calcified plaque inside the artery walls
• How much buildup is present
• Where the plaque is located
• Your overall risk of a future heart event
  
  

This is information you cannot get from a stress test. Even people who feel perfectly healthy or perform well during exercise can score high on a heart scan because plaque develops silently.

Why You Can Pass a Stress Test and Still Have Plaque

Stress tests detect problems that occur during exertion, not the presence of plaque itself. A narrowing in an artery does not always interfere with blood flow during exercise especially in early stages. That’s why heart scans are so valuable for prevention.

Someone may:

• Have plaque forming quietly
• Feel totally fine during workouts
• Pass a stress test with normal results
• Yet still have a high calcium score showing real risk

The heart scan catches what a stress test cannot: structural changes that begin long before symptoms.

A Practical Takeaway

A stress test shows how your heart performs.
A heart scan shows what’s happening inside your arteries.

Together, they offer two very different pieces of information. You can have normal exercise performance and still have hidden plaque and that’s exactly why heart scans are used for early detection.

What Does the Mayo Clinic Say About Early Heart Detection?

According to the Mayo Clinic, coronary calcium scoring can reveal plaque long before symptoms appear, allowing patients and doctors to take action earlier. Their guidance emphasizes that CT calcium scoring is one of the most reliable ways to detect coronary artery disease in its early stages especially in people who feel healthy or have normal stress test results.

Key points the Mayo Clinic highlights:

• Calcium scans identify plaque that cannot be seen through stress testing
• They help predict future heart disease, even without symptoms
• The test is quick, noninvasive, and highly accurate
• A normal stress test does not rule out underlying plaque
• Early detection improves prevention and long-term outcomes
  
  

For more information, visit the Mayo Clinic:
https://www.mayoclinic.org/tests-procedures/heart-scan/about/pac-20384686