Duke Treadmill Score Calculator

Created by Joanna Michałowska, PhD candidate
Reviewed by Dominik Czernia, PhD candidate and Jack Bowater
Last updated: Feb 15, 2022

The Duke treadmill score calculator predicts the risk of ischemia or infraction in the heart. The Duke score is based on the treadmill exercise test and we use it to predict prognosis and plan further treatment for patients with suspected coronary artery disease.

In the article below to you will find more information about this coronary artery disease test and it's components.

We try our best to make our Omni Calculators as precise and reliable as possible. However, this tool can never replace professional medical advice.

Coronary artery disease

Coronary artery disease (CAD) is the most common type of heart disease in the United States. Its other names include coronary heart disease or ischemic heart disease. For some people, the first sign of CAD can be a heart attack; however, many patients experience various symptoms of this illness beforehand.

Coronary artery disease is caused by plaque buildup in the walls of the arteries, which supply blood to the heart, and other parts of the human body. The plaque, built from cholesterol and other substances, successively narrows the arteries, which limits the blood flow or can block it entirely.

The symptoms and complications of CAD include:

  • angina;
  • chest pain and discomfort;
  • heart attack (weakness, nausea, angina, chest pain, cold sweat, and shortness of breath); and
  • heart failure (dyspnea, fatigue, shortness of breath, swelling in the legs, rapid and irregular heartbeat).

The risk factors for CAD include:

If a patient is at a high risk of heart disease or already has symptoms, the doctor can use several tests to diagnose CAD. One of the coronary artery disease tests is exercise stress test. Use the Duke treadmill score calculator to obtain the information required to assess the patient's health.

Duke treadmill score

The Duke Treadmill Score is a weighted index using treadmill exercise time (performed according to the standard Bruce protocol), maximum net ST-segment deviation (depression or elevation), and exercise-induced angina. It was developed to provide diagnostic and prognostic information to help evaluate patients with suspected coronary heart disease.

The typical observed range for Duke treadmill score starts from -25 (the highest risk) up to +15 (the lowest risk).

The Duke score equation is as following:

Duke score = exercise – 5 * ST-segment dev. – 4 * TAI,


  • exercise is the duration of exercise expressed in minutes;

  • ST-segment dev. is the maximal net ST-segment deviation expressed in millimeters. ST deviation refers to maximum ST change (elevation or depression) in any lead except lead aVR; and

  • TAI is the Treadmill Angina Index, that we can describe as follows:

Treadmill angina index
no angina/pain
typical angina (pain limited to the exercise period)
exercise stopped, because of angina

Coronary artery disease test (Duke score) - interpretation

According to the Duke treadmill score, patients are categorized as low-risk, intermediate-risk or high-risk.

Interpretation is based on a paper by Mark BD et al. 1991:

Risk group
Survival at 4 years
-10 to +4
less than -10

Duke treadmill score calculator - a practical example

Let's use a practical example to show how the Duke treadmill score calculator works.

The patient named Susan took a Duke treadmill test. She was exercising for 8 minutes, and didn't experience any pain during the test. Her maximal net ST-segment deviation was equal to 0.6 mm.

The Duke score will be calculated as follows:

  1. Duke score = exercise – 5 * ST-segment dev. – 4 * TAI

  2. Duke score = 8 min – 5 × 0.6 mm – 4 × 0

  3. Duke score = 8 - 3

  4. Duke score = 5

Interpretation: Susan is a low-risk patient.

Joanna Michałowska, PhD candidate
Max ST-segment deviation
Angina index
No angina during exercise
Duke treadmill score
Results interpretation:
ScoreRisk groupSurvival at 4 years
-10 to 4Medium95%
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