Duke Treadmill Score Calculator

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Walk-through

How to Use This Calculator

4 steps

1

Enter exercise time, ST deviation, and angina index

Type the total treadmill exercise time in minutes (Bruce protocol), the maximum ST-segment deviation from the exercise ECG in millimeters, and select the angina index — 0 (none), 1 (non-limiting), or 2 (exercise-limiting) — or click a preset to fill a realistic scenario. The calculator updates instantly as you type.

2

Read the score and its risk tier

The headline shows the Duke Treadmill Score, with a colour-coded tier: Low risk, Moderate risk, or High risk. The interpretation line under the result restates the score and its risk tier in one sentence.

3

Check the risk-tier reference table

Open the Risk Tier tab for the full score-range table and an explanation of how the three components of the score combine — why exercise time adds points while ST deviation and angina subtract them.

4

Review the 5-year survival estimate

Open the 5-Year Survival tab to see approximate survival and annual mortality for each risk tier, drawn from the original Duke cohort studies. Use Share or Copy to save a reading — your inputs are encoded in the URL.

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Reference

Formula & Methodology

1 formula

Duke Treadmill Score

DTS = Exercise time (min) − (5 × ST-segment deviation, mm) − (4 × Angina index)

Exercise time is the total time completed on a standard Bruce-protocol treadmill test, in minutes. ST-segment deviation is the maximum horizontal or downsloping depression (or elevation) seen on the exercise ECG, in millimeters. Angina index is 0 for no angina, 1 for angina that did not require stopping the test, or 2 for angina severe enough that the test was terminated. Both ST deviation and angina subtract points because each reflects exercise-induced ischemia; more exercise time adds points because it reflects better functional capacity.

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High YMYL

Trust, Methodology & Sources

Reviewed by Calculover Editorial Review · Updated 2026-07-22 · 2 sources

Editorial accountability

Author: Calculover Editorial Team - Editor

Owner: Calculover Editorial Team - Editorial owner

Reviewer: Calculover Editorial Review - Medical-source review

Last reviewed: 2026-07-22

Last verified: 2026-07-22

Data effective: 2026-07-22

Methodology

The Duke Treadmill Score Calculator applies the standard clinical formula DTS = exercise time (minutes) - (5 x ST-segment deviation in mm) - (4 x angina index) to the values entered by the user. Risk tiers (low risk >= 5, moderate risk -10 to 4, high risk <= -11) and the associated annual cardiac mortality rates (approximately 0.25%, 1.25%, and 5% per year respectively) and derived 5-year survival estimates (approximately 97%, 90%, and 65%) are drawn from Mark DB et al., Ann Intern Med. 1987;106(6):793-800, and the prospective validation in Mark DB et al., N Engl J Med. 1991;325(12):849-853.

Assumption: Exercise time reflects a standard Bruce-protocol treadmill test; times from other protocols should be converted to a Bruce-equivalent value before use.

Assumption: ST-segment deviation and angina classification (non-limiting vs. exercise-limiting) are determined by a qualified clinician supervising the ECG-monitored test.

Assumption: The user wants a screening estimate and educational context, not a diagnosis, treatment plan, or a substitute for supervised stress testing interpreted by a clinician.

Limitations & guidance

Risk tiers and survival estimates are population-level figures from the original Duke cohorts, not individualized predictions for any one patient.

The score does not account for other clinical factors (e.g. resting ECG abnormalities, medications such as beta-blockers that blunt heart-rate response, or comorbidities) that a clinician would also weigh.

This tool does not diagnose coronary artery disease, does not replace a supervised stress test, and does not guide treatment on its own. Do not make medical decisions based solely on its output.

Professional guidance: The Duke Treadmill Score Calculator is a clinical decision-support and education tool. It provides a research-derived risk estimate, not medical advice, diagnosis, treatment, or a substitute for care from a licensed healthcare professional. Evaluating stress-test results and next steps requires a supervised, ECG-monitored test interpreted by a qualified clinician.

Primary sources

Mark DB, Hlatky MA, Harrell FE Jr, Lee KL, Califf RM, Pryor DB. Exercise treadmill score for predicting prognosis in coronary artery disease. Ann Intern Med. 1987;106(6):793-800. - Annals of Internal Medicine (American College of Physicians)

Mark DB, Shaw L, Harrell FE Jr, et al. Prognostic value of a treadmill exercise score in outpatients with suspected coronary artery disease. N Engl J Med. 1991;325(12):849-853. - New England Journal of Medicine (Massachusetts Medical Society)

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Glossary

Key Terms Explained

7 terms

Duke Treadmill Score A validated risk score for outpatients with suspected coronary artery disease, computed from exercise time, ST-segment deviation, and angina during a Bruce-protocol treadmill stress test. Higher scores indicate lower risk.

Bruce protocol The most widely used graded treadmill exercise test protocol, increasing speed and incline every three minutes. The Duke Treadmill Score was derived and validated using Bruce-protocol exercise time; other protocols should be converted to a Bruce-equivalent time before use.

ST deviation The maximum horizontal or downsloping depression (or elevation) of the ST segment on the exercise ECG, measured in millimeters. A larger deviation subtracts more points from the score and reflects more pronounced exercise-induced ischemia.

Angina index A 0–2 scale describing chest pain during the test: 0 = no angina, 1 = non-limiting angina (present but the test was completed), 2 = exercise-limiting angina (severe enough that the test was stopped).

Exercise stress test A supervised test, typically on a treadmill or stationary bike, that raises heart rate and blood pressure in graded stages with ECG monitoring, used to evaluate cardiovascular fitness or detect exercise-induced ischemia.

Prognosis An estimate of likely clinical outcome — here, the probability of survival over a defined period — based on patient characteristics and test results, rather than a certainty for any one individual.

5-year survival The approximate probability of surviving five years, estimated here from the annual cardiac mortality rate reported for each Duke Treadmill Score risk tier in the original cohort studies.

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Scenarios

Real-World Examples

3 worked examples

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Diane, 58 — routine stress test, asymptomatic

Low-risk result, 12 min / 0mm / no angina

Exercise time 12 min ST deviation 0 mm Angina index 0 — none Duke Treadmill Score 12

DTS = 12 − (5 × 0) − (4 × 0) = 12 — comfortably in the Low risk tier (score ≥ 5), corresponding to roughly 97% 5-year survival in the original cohort.

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Frank, 61 — mild chest tightness at moderate exertion

Moderate-risk result, 6 min / 1mm / non-limiting angina

Exercise time 6 min ST deviation 1 mm Angina index 1 — non-limiting Duke Treadmill Score -3

DTS = 6 − (5 × 1) − (4 × 1) = -3 — in the Moderate risk tier (-10 to +4), corresponding to roughly 90% 5-year survival. Frank's shorter exercise time and mild ST deviation, combined with non-limiting angina, place him well above the low-risk cutoff but below it.

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Robert, 67 — test terminated early for limiting angina

High-risk result, 3 min / 2mm / exercise-limiting angina

Exercise time 3 min ST deviation 2 mm Angina index 2 — exercise-limiting Duke Treadmill Score -15

DTS = 3 − (5 × 2) − (4 × 2) = -15 — in the High risk tier (score ≤ -11), corresponding to roughly 65% 5-year survival. The combination of very short exercise time, marked ST deviation, and a test stopped for angina all push the score sharply negative — this pattern typically prompts further workup such as cardiac catheterization.

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Deep Dive

Understanding the Duke Treadmill Score

3 chapters · 4 min read

The Duke Treadmill Score is one of the most extensively validated tools in cardiology for estimating prognosis after an exercise stress test. By combining exercise time, ST-segment changes, and angina into a single number, it turns a routine treadmill test into a risk-stratification tool that helps decide who needs further cardiac workup and who can be managed conservatively. This guide explains how the score is built, what its risk tiers mean, and where its limits are.

How the score is built and where it comes from

The Duke Treadmill Score was derived by Mark and colleagues (Annals of Internal Medicine, 1987) from 2,842 patients undergoing treadmill testing at Duke University Medical Center, and prospectively validated in 613 outpatients with suspected coronary artery disease (New England Journal of Medicine, 1991). The formula is DTS = exercise time (minutes) − (5 × ST-segment deviation in mm) − (4 × angina index).

Exercise time reflects overall functional capacity — the longer a patient can exercise on a standard Bruce-protocol treadmill, the better their prognosis tends to be. ST-segment deviation and angina both subtract points because they are markers of exercise-induced myocardial ischemia — reduced blood flow to the heart muscle during exertion.

Reading the risk tiers and survival estimates

The original studies grouped patients into three risk tiers by score: low risk (≥ +5), moderate risk (−10 to +4), and high risk (≤ −11). These tiers correspond to reported annual cardiac mortality rates of roughly 0.25%, 1.25%, and 5% per year respectively — translating to approximate 5-year survival of about 97%, 90%, and 65%.

These figures describe average outcomes for outpatients with suspected coronary artery disease who were referred for treadmill testing in the original Duke cohorts. They are population-level estimates, not a guarantee for any individual patient — a high-risk score is typically used to prioritize a patient for further evaluation, such as cardiac catheterization, rather than to predict an exact outcome.

Limits and when to seek expert review

The Bruce protocol assumption matters: exercise time from other treadmill or bicycle protocols should be converted to a Bruce-equivalent time before applying this formula, since a different protocol's minutes are not directly comparable. The score also depends on a supervised, ECG-monitored test correctly identifying ST-segment deviation and correctly classifying angina as non-limiting versus exercise-limiting — both judgment calls made by the clinician administering the test.

This calculator is a clinical decision-support and education tool. It does not diagnose coronary artery disease, does not replace a supervised stress test interpreted by a qualified clinician, and should not be used as the sole basis for a treatment decision.

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Questions

Frequently Asked Questions

6 questions

What is the formula for the Duke Treadmill Score?+

DTS = Exercise time (minutes) − (5 × ST-segment deviation in mm) − (4 × angina index). For example, 12 minutes of exercise with no ST deviation and no angina gives DTS = 12 − 0 − 0 = 12.

What does the angina index scale mean?+

The angina index is 0 for no angina during the test, 1 for non-limiting angina (present, but the patient completed the test), and 2 for exercise-limiting angina (chest pain severe enough that the test was stopped).

Does the Duke Treadmill Score assume the Bruce protocol?+

Yes. Exercise time in the formula refers to time on a standard Bruce-protocol treadmill test. If a different protocol was used, exercise time should be converted to a Bruce-equivalent value (for example, using estimated METs) before applying the formula.

What are the Duke Treadmill Score risk tiers?+

Low risk is a score of +5 or higher, moderate risk is -10 to +4, and high risk is -11 or lower. These cutoffs come from the original Duke cohort studies and are used to stratify patients for further cardiac workup.

What is the 5-year survival for each risk tier?+

Based on the annual cardiac mortality reported in the original cohorts (about 0.25%/year low risk, 1.25%/year moderate risk, 5%/year high risk), approximate 5-year survival is roughly 97% for low risk, 90% for moderate risk, and 65% for high risk. These are population-level estimates, not individual predictions.

How is the Duke Treadmill Score used clinically?+

It helps stratify outpatients with suspected coronary artery disease after a stress test — a low-risk score generally supports conservative management, while a high-risk score typically prompts further evaluation such as cardiac catheterization or imaging. It is a decision-support tool, not a substitute for a clinician's overall judgment.

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