If you’ve been scheduled for a cardiac stress test, you’ve probably heard the term “METS” and wondered what it means. Understanding what is METS in treadmill test results is key to knowing how your heart performs under pressure.
This article explains METS in simple terms. We’ll cover what they measure, why they matter for your health, and how to interpret your score.
What Is METS In Treadmill Test
METS stands for Metabolic Equivalent of Task. It’s a unit that doctors use to measure how much energy your body uses during an activity. One MET is defined as the amount of oxygen your body consumes while at complete rest.
During a treadmill test, the METS score tells us how hard your heart is working compared to that resting state. If you reach 10 METS, it means you’re using ten times the oxygen and energy than you would while sitting quietly.
Why METS Matter for Your Heart Health
Your heart’s ability to supply oxygen-rich blood to your muscles under stress is a direct indicator of its fitness. A higher METS capacity generally suggests a stronger, more efficient cardiovascular system.
Doctors use your achieved METS to:
- Assess your overall cardiovascular fitness level.
- Help diagnose potential coronary artery disease.
- Evaluate the effectiveness of cardiac treatments or rehabilitation.
- Provide guidance for safe exercise levels after a cardiac event.
How a Standard Treadmill Test Works
The most common protocol is the Bruce Protocol. It involves walking on a treadmill that gets steeper and faster every three minutes. You’re connected to an ECG machine to monitor your heart’s electrical activity throughout.
The test continues until you reach a target heart rate, experience symptoms like chest pain, or become to fatigued to continue. The stage you reach determines your final METS score.
Typical METS Values by Bruce Protocol Stage
Here’s a general guide to the METS levels at each stage. Remember, individual results can vary based on age and gender.
- Stage 1 (1.7 mph, 10% incline): ~4.6 METS
- Stage 2 (2.5 mph, 12% incline): ~7.0 METS
- Stage 3 (3.4 mph, 14% incline): ~10.1 METS
- Stage 4 (4.2 mph, 16% incline): ~13.5 METS
- Stage 5 (5.0 mph, 18% incline): ~16.8 METS
Interpreting Your METS Score: What’s Good?
There’s no single “good” score for everyone. Your expected METS level depends heavily on you age and sex. A 25-year-old athlete will have a much higher expected capacity than a 70-year-old.
Generally, achieving 10 METS or more is considered an excellent result for most adults. It often correlates with a lower risk of cardiovascular events. Scores below 5-6 METS may indicate a lower fitness level or potential heart issues, which your doctor will analyze with other test data.
Factors That Can Influence Your METS Result
Several things besides heart health can affect your score. It’s important to consider the whole picture.
- Age: METS capacity naturally declines as we get older.
- Sex: Men often, but not always, achieve slightly higher scores than women.
- Regular Exercise: Those who are physically active typically score higher.
- Muscle Mass: Body composition plays a role in energy expenditure.
- Test Effort: Your personal motivation and effort during the test directly impact the result.
Beyond the Number: Other Key Test Outcomes
While METS are important, doctors look at a full set of data from your stress test. The METS score is just one piece of the puzzle.
They also carefully review your heart rate response, blood pressure changes, and most crucially, any ECG abnormalities or symptoms that occured during the test. A high METS score with chest pain and ECG changes is very different than a low METS score without any other issues.
Using Your Results to Improve Fitness
If your METS score was lower than expected, don’t be discouraged. It’s a starting point. Your doctor or a cardiac rehab specialist can use this number to create a safe, effective exercise plan for you.
The goal is to gradually increase your functional capacity over time. For example, if you achieved 6 METS, a plan might aim to safely build you up to 8 or 9 METS through regualr, guided exercise.
Steps to Safely Build Your METS Capacity
- Get Clearance: Always follow your doctor’s advice before starting a new exercise routine.
- Start Slow: Begin with moderate activities like brisk walking, aiming for 20-30 minutes most days.
- Use the “Talk Test”: Exercise at a pace where you can still hold a conversation but not sing.
- Add Intensity Gradually: Slowly include hills, intervals, or increase speed as your fitness improves.
- Monitor Progress: You’ll feel your stamina increase in daily activities, like climbing stairs with less effort.
Common Questions About METS and Treadmill Tests
What’s a normal METS score for my age?
Normal varies widely. There are published tables your doctor uses. For a rough idea, an average 50-year-old man might aim for 9-10 METS, while an average 50-year-old woman might aim for 8-9 METS. But individual health is the real decider.
Can I improve my METS score?
Absolutely. With consistent aerobic exercise like walking, cycling, or swimming, you can significantly improve your cardiovascular fitness and your METS capacity. This is a central goal of cardiac rehabilitation programs.
Is a home treadmill METS reading accurate?
Home treadmills often estimate METS using formulas based on speed and incline, but they lack the medical monitoring of a clinical test. They can give you a general fitness trend but should not be used for medical diagnosis. The clinical test is far more precise.
What if I couldn’t finish the test due to knee pain?
This is common. If joint pain or other non-cardiac issues stop the test, your METS score reflects your functional limitation, not necessarily your heart’s true capacity. Your doctor may consider alternative tests, like a pharmacological stress test with imaging.
How does METS relate to my risk of heart problems?
Research consistently shows that a higher achieved METS level is associated with a lower risk of future heart-related events. It’s a powerful predictor of long-term cardiovascular health, which is why doctors pay close attention to it.
In summary, your METS score from a treadmill test is a practical measure of your heart’s work capacity. It provides a valuable snapshot of your cardiovascular fitness and helps guide important health decisions. By understanding this number, you can better partner with your doctor to manage your heart health for years to come.