10 Things You Need to Know About the Treadmill Stress Test (TMT)

Key Takeaways

• A stress test monitors your heart's activity while you walk or run on a treadmill.

• It helps doctors see how your heart works under physical stress.

• The test can reveal heart problems such as coronary artery disease that might not be noticeable at rest.

• Your doctor will attach sensors to your chest to monitor your heart rate and blood pressure as you exercise.

• Follow all specific instructions from your doctor to ensure accurate results.

Introduction

Cardiovascular diseases (CVD) in India have surged alarmingly, escalating from 2.57 crore in 1990 to a staggering 6.4 crore cases in 2023. This heightened risk is attributed to a combination of genetics, sedentary lifestyles, stress, unhealthy dietary habits, and the prevalence of conditions like uncontrolled diabetes, high cholesterol and hypertension.

• The rates of coronary artery disease (CAD) among Indians are a staggering 50-400% higher than any other ethnic group.  

• Nearly 50% of first heart attacks in Indians occur before the age of 50, and 25% occur before the age of 40.  

Given these statistics, awareness of cardiac risk assessment is crucial. One effective method for evaluating heart function and predicting potential heart-related issues is the treadmill stress test, a simple yet powerful tool for identifying risks before they become life-threatening.

Case Samples

• Take the case of Rajesh, a 45-year-old IT professional. Despite his healthy lifestyle, he started experiencing occasional chest discomfort during his morning runs. Concerned about his health due to his father's history of CAD, he consulted a cardiologist who recommended a treadmill stress test. The test revealed that Rajesh's heart responded well to exercise, easing his worries about his chest discomfort. With his cardiologist's guidance, he adjusted his running routine and incorporated more structured warm-ups, ensuring safer workouts.

• Similarly, consider Ritu, a 55-year-old homemaker with high cholesterol, who recently joined a gym to improve her fitness. As a first-time gym-goer, she was eager to ensure her heart was up to the challenge. During the stress test, abnormalities in her ECG were detected. Ritu's cardiologist assured her that with careful exercise and proper management, she could safely maintain her fitness regimen. This knowledge empowered Ritu to adjust her workouts under professional guidance, ensuring she could stay active while effectively managing her CAD.

What Exactly Is a TMT Test?

A treadmill stress test simulates exercise while doctors monitor your heart rate, blood pressure, and electrocardiogram (ECG).  

It helps assess how your heart responds to physical activity, revealing potential health issues.

Why Should You Care About This Test?

The stress test is a powerful tool for spotting heart issues like coronary artery disease (CAD) and heart rhythm problems.  

CAD happens when the arteries that supply blood to your heart get clogged, raising your risk of a heart attack.  

By seeing how your heart works under stress, doctors can catch problems early.

Benefits of a Treadmill Stress Test

1. Early detection and treatment of heart issues
2. Treatment monitoring
3. Safe exercise guidelinestailored to your heart’s health

What does the stress test measure?

• Blood pressure

• Heart rate

• Oxygen levels

• Electrical activity in the heart

• How hard the heart is working compared to others of the same age and sex

‍List of heart abnormalities that can be identified during a stress test

Who Should Consider a TMT Test?

You should consider this test:

• If you experience chest pain or discomfort, shortness of breath, etc

• Have a family history of heart disease

• Show symptoms during exercise including chest pain or discomfort, shortness of breath, dizziness, or extreme fatigue

• Are in high-risk occupations, such as pilots or professional athletes

• Want to begin an exercise program

• Have diabetes or other underlying conditions that increase the risk of heart disease

• Need non-cardiac surgery, with healthcare providers needing to assess the risk of complications

What happens during the TMT test?

The test usually lasts 15 to 30 minutes, monitoring vital signs to evaluate your heart's response.

• Small electrodes will be placed on your chest to monitor your heart.

• You will be asked to walk or run on a treadmill.

• You'll begin slowly on the treadmill, gradually increasing speed and incline.  

Getting ready for the test

• Wear loose clothing and supportive shoes.

• Discuss all medications with your doctor.

• Avoid food, smoking, alcohol and caffeine three hours before the test.

Understanding your results

• Normal: Your heart health is great.

• Abnormal: Possible CAD or other concerns, warranting further evaluation such as coronary angiography, nuclear stress test, CT coronary angiogram, etc.  

Common parameters indicating an abnormal treadmill stress test include:

• Experiencing chest pain or discomfort, shortness of breath, dizziness or excessive fatigue during exercise

• Noticing a drop in blood pressure during exercise

• Noticing irregular heart rhythm during exercise

• Noticing ECG abnormalities such as deviation in the ST segment  

Are there any risks?

While generally safe, risks include physical exertion and rare complications, including  

• Irregular heartbeats

• Chest pain  

• Dizziness or fainting  

• In very rare cases, a heart attack could occur in individuals with underlying heart disease.

However, the benefits of early detection outweigh these risks.

It's also important to note that doctors are prepared to handle any emergencies that may arise during the test.  

Are there any contraindications?

Yes, there are some situations where a stress test may not be recommended or should be approached with caution. These may include:

• A recent heart attack  

• If you are experiencing chest pain at rest or increasing in frequency or severity

• Certain heart conditions such as irregular heart rhythms, valve issues or uncontrolled hypertension  

• Severe infections  

• Electrolyte imbalance

• Mental or physical impairment which limits exercising capacity

After the test: what’s next?

Based on your results, your doctor might suggest  

• Further investigations such as coronary angiography, nuclear stress test, CT coronary angiogram, etc in case of abnormal stress test

• Medications

• Lifestyle changes including  

Interesting fact

A recent 2023 study showed that treadmill stress test can predict not just heart-related deaths, but also deaths from other causes, such as cancer and dementia.

Factors like poor heart function during exercise, slow heart rate recovery, and low heart rate response were linked to higher risks of non-heart-related deaths. ‍

Conclusion

Regular heart check-ups, including treadmill stress test, are essential for maintaining a healthy heart. Consult your doctor to see if a stress test is right for you and take proactive steps towards better heart health.

Also, consider downloading the Aware Health Rewards app today. By staying informed and proactive, you can help prevent a heart attack tomorrow. Your heart health matters—take charge of it now.

FAQ's

1. What happens if I can't exercise for a stress test? Is there an alternative?

Yes, there is an alternative if you cannot exercise for a stress test. Your doctor can use a specific medication to simulate the effects of exercise on your heart. In this case, the doctor will attach electrodes to your chest and administer the medication through an intravenous line in your arm. This medication will stimulate your heart and produce effects similar to those experienced during physical exercise, such as flushing or shortness of breath. This allows your doctor to assess your heart’s function under stress even if you are unable to perform physical activity.

2. What are the other types of stress tests, and how do they work?

There are two other types of stress tests:

• Nuclear Stress Test (Thallium Stress Test): Similar to the exercise stress test, but with an additional step. You will receive a dye via an intravenous line in your arm, which allows doctors to view images of your heart using a special camera. This helps to see the blood flow to your heart muscle.

• Stress Echocardiogram: This test combines the exercise stress test with an echocardiogram. During the test, a doctor will hold a transducer against your chest. The transducer creates sound waves that produce moving pictures of your heart, allowing your doctor to see how well your heart functions during exercise.

3. Can treadmill stress test yield false positive and false negative results? How accurate is the diagnosis?

Yes. A treadmill stress test can sometimes indicate heart issues that are not present (false positives) or miss existing heart problems (false negatives). The accuracy of the test hinges on factors like the doctor's expertise, result interpretation, and the patient's overall health condition. Due to these factors, the doctor may suggest further tests to confirm a diagnosis when needed.

4. What is the sensitivity and specificity of the treadmill stress test?

• Sensitivity measures the test's ability to correctly identify people who have heart issues. A high sensitivity means fewer cases are missed (fewer false negatives). The TMT test has a sensitivity of about 50-60%.
• Specificity measures the test's ability to correctly identify people who do not have heart problems. A high specificity means fewer healthy individuals are incorrectly diagnosed (fewer false positives). The TMT test has a specificity of about 85%.  

References

1. Exercise stress test. American Heart Association

2. Exercise stress test. National Library of Medicine

3. Vilcant V, Zeltser R. Treadmill Stress Testing. [Updated 2023 Jun 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-

4. Sydó N, et al. Exercise test predicts both noncardiovascular and cardiovascular death in a primary prevention population. Mayo Clin Proc. 2023;98(9):1297-1309. .  

5. Fletcher GF, et al. Exercise standards for testing and training: A scientific statement from the American Heart Association. Circulation. 2013;128(8). .  

6. Kharabsheh SM, et al. Overview of exercise stress testing. Ann Saudi Med. 2006;26(1):1-6. doi: 10.5144/0256-4947.2006.1.

About the Authors
‍
Dr. Satish Madiraju, a renowned cardiologist is passionate about consumer heart health and is on a mission to prevent a million heart attacks. He shares his expertise not only on heart health but also on leadership, digital health, and improving patient experience.