# Treadmill Testing > Treadmill testing for Cardiac Technology: Bruce protocol stages, target heart rate, positive criteria, endpoints and contraindications for exercise ECG. - Canonical URL: https://prepelephant.com/topics/allied/cardiac-technology/treadmill-testing-ct - Exam / course: Allied Health · Subject: Cardiac Technology - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Treadmill Testing", PrepElephant, https://prepelephant.com/topics/allied/cardiac-technology/treadmill-testing-ct ## Direct answer Graded exercise testing walks the heart into ischaemia on a treadmill while the cardiac technologist watches: the Bruce protocol raises speed and gradient every three minutes (stage one begins at 1.7 miles per hour on a 10 per cent grade), the ECG is displayed continuously, blood pressure is taken at every stage, and the test runs until the target heart rate of 85 per cent of 220 minus age is reached or an endpoint appears — reproducible chest pain, a fall in systolic pressure despite rising workload, or at least 1 mm of horizontal or downsloping ST depression 60-80 ms after the J point. A defibrillator and trained staff are in the room for every test, and a short list of absolute contraindications decides who never steps on the belt. ## What you must remember - Bruce protocol stages (3 minutes each): I 1.7 mph at 10 per cent, II 2.5 at 12, III 3.4 at 14, IV 4.2 at 16, V 5.0 at 18, VI 5.5 at 20, VII 6.0 at 22. - Modified Bruce adds stage 0 (1.7 mph at 0 per cent) and stage 0.5 (1.7 at 5 per cent) as warm-up stages for post-infarction, elderly or deconditioned patients. - Positive ECG criteria: at least 1 mm (0.1 mV) of horizontal or downsloping ST depression, or ST elevation, persisting at least three consecutive beats and measured 60-80 ms after the J point; upsloping depression is less specific. - Target heart rate: 85 per cent of the predicted maximum (220 minus age); reaching it makes the test adequate, and failing to rise appropriately (chronotropic incompetence) is itself an adverse prognostic marker. - Stop the test for: patient request, limiting chest pain, a fall in systolic pressure of more than 10 mmHg from baseline despite rising workload, 2 mm or more of progressive ST change, ST elevation, sustained ventricular tachycardia, ataxia or severe exhaustion. - Absolute contraindications: acute myocardial infarction within 48 hours, unstable angina, uncontrolled arrhythmia with haemodynamic compromise, symptomatic severe aortic stenosis, decompensated heart failure, acute aortic dissection, active myocarditis or pericarditis, and severe uncontrolled hypertension (commonly above 200/110 mmHg at rest). - Electrode placement uses the Mason-Likar modification (limb electrodes on the torso) so the arms can swing; check the tracing with the patient standing before the test. - Duke treadmill score: exercise minutes minus (5 times the largest ST deviation in mm) minus (4 times the angina index, 0-2); +5 or more is low risk, -11 or less high risk. - False positives are real: digoxin, left ventricular hypertrophy, pre-excitation, electrolyte disturbance and, statistically, women reduce specificity. ## Running a test, minute by minute The patient is fasted about two to three hours, has avoided smoking and caffeine that day, and continues usual medicines unless specified — note that beta-blockers blunt the heart-rate response and may make the test submaximal, a fact worth stating in the report rather than silently stopping the drug. Fit the electrodes by Mason-Likar positions, verify signal quality with the patient standing, and demonstrate the treadmill: the belt speed of stage one, the handrail rule (for balance only — leaning steals workload and inflates the apparent exercise time), and the agreed signal to stop. Endpoints are called on criteria, not politeness — a patient who "prefers to continue" with 2.5 mm of ST depression is stopped, as is a systolic pressure dipping below baseline as workload rises. ## Where students slip Three errors recur. The blood-pressure fall is misread: a dropping systolic pressure with rising workload is not fatigue, it is an endpoint and an ominous one, suggesting global ischaemia or left main disease. Upsloping ST depression is quoted as a positive criterion, when strictly horizontal and downsloping segments (60-80 ms after J) are the diagnostic ones. The arithmetic confusions: 85 per cent of 220 minus age (a 60-year-old targets about 136, not 160), and the Duke score multiplies ST deviation by five and angina index by four — sign errors flip a low-risk patient into a high-risk report. ## Frequently asked questions ### What heart rate defines an adequate exercise test? Eighty-five per cent of the predicted maximum, calculated as 220 minus age. Reaching it makes a negative result meaningful; a test stopped well below it is reported as non-diagnostic. ### What are the ECG criteria for a positive treadmill test? At least 1 mm of horizontal or downsloping ST depression (or ST elevation) measured 60-80 ms after the J point, persisting for at least three consecutive beats in a lead with a normal baseline. ### Which three conditions are absolute contraindications to exercise testing? Unstable angina, acute myocardial infarction within the previous 48 hours, and decompensated heart failure — others include severe symptomatic aortic stenosis, acute aortic dissection and uncontrolled haemodynamically significant arrhythmia. ### What is the Duke treadmill score and how is it interpreted? Exercise minutes minus five times the maximum ST deviation in millimetres minus four times the angina index (0 none, 1 non-limiting, 2 limiting). Scores of +5 or more indicate low risk and -11 or less high risk.