What are the guidelines and procedures for a treadmill test?

Treadmill Test Guidelines and Procedures

The standard treadmill test should be performed on a motor-driven treadmill with adjustable speed and grade, using a 12-lead ECG configuration for monitoring, with the patient exercising to reach 80-90% of their predicted maximum heart rate (calculated as 220 - age in years) for at least 4 minutes. 1

Equipment Requirements

For Standard Exercise Treadmill Test

• Motor-driven treadmill with adjustable speed and grade
• ECG monitoring system (minimum 3-lead, preferably 12-lead)
• Blood pressure measurement equipment
• Emergency resuscitation cart with defibrillator
• Oxygen source and suction equipment
• Countdown timer or stopwatch
• Appropriate documentation forms 1

For Metabolic Exercise Testing (if applicable)

• Gas exchange system with O₂ and CO₂ analyzers
• Pulse oximeter
• Mouthpiece and breathing valve 1, 2

Patient Preparation

Before Arrival

• Provide written information about the test
• Instruct patient to:
  • Wear comfortable exercise clothing and athletic shoes
  • Avoid caffeine on the day of the test
  • Avoid heavy meals within 2-3 hours of testing
  • Avoid vigorous exercise for at least 4 hours before the test 1

Medication Considerations

• Continue usual medications unless specifically instructed otherwise
• Consider withholding:
  • Beta-blockers (if assessment of maximum heart rate is needed)
  • Antihistamines (48 hours prior if testing for exercise-induced bronchoconstriction) 1

Pre-Test Procedures

1. Review contraindications:

   • Acute myocardial infarction (within 2 days)
   • Unstable angina
   • Uncontrolled cardiac arrhythmias
   • Symptomatic severe aortic stenosis
   • Uncontrolled heart failure
   • Acute pulmonary embolism
   • Acute myocarditis or pericarditis
   • Acute aortic dissection
   • Unstable cardiac ischemia
   • Malignant arrhythmias
   • Orthopedic limitations preventing adequate exercise 1

2. Obtain baseline measurements:

   • 12-lead ECG (for patients over 60, a recent ECG should be available)
   • Blood pressure
   • Heart rate
   • Oxygen saturation (if applicable)
   • Dyspnea rating using Borg scale 1, 2

3. Prepare the patient:

   • Explain the test procedure
   • Apply ECG electrodes in modified Mason-Likar placement
   • Ensure proper skin preparation by cleansing with alcohol and gentle abrasion 1

Treadmill Test Protocol

Standard Protocol

1. Begin at low speed and grade
2. Progressively advance both during first 2-3 minutes
3. Target heart rate: 80-90% of predicted maximum (220 - age in years)
4. Alternative target: Ventilation at 40-60% of predicted maximum voluntary ventilation (MVV, estimated as FEV1 × 35)
5. Maintain target for at least 4 minutes
6. Total exercise duration: 6-8 minutes (6 minutes for children under 12,8 minutes for older children and adults) 1

Treadmill Settings

• Speed typically greater than 3 mph (4.5 km/h)
• Gradient typically greater than 15%
• Oxygen consumption target: 35 ml/min/kg or greater 1

Monitoring During Test

• Continuous ECG monitoring
• Blood pressure measurements every 2-3 minutes
• Heart rate monitoring
• Symptoms (chest pain, dyspnea, fatigue, dizziness)
• Reason for termination if test ends prematurely 1

Test Termination Criteria

Absolute Indications

• Drop in systolic blood pressure >10 mmHg with increasing workload
• Moderate to severe angina
• Increasing nervous system symptoms (ataxia, dizziness)
• Signs of poor perfusion (cyanosis, pallor)
• Technical difficulties monitoring ECG or blood pressure
• Subject's request to stop
• Sustained ventricular tachycardia
• ST elevation (≥1.0 mm) in leads without diagnostic Q waves 1

Relative Indications

• ST or QRS changes such as excessive ST depression (>2 mm horizontal or downsloping)
• Fatigue, shortness of breath, wheezing
• Leg cramps or claudication
• Hypertensive response (systolic >250 mmHg, diastolic >115 mmHg) 1

Post-Test Procedures

1. Cool-down period:

   • Continue walking at slow pace
   • Monitor ECG, blood pressure, and symptoms

2. Recovery monitoring:

   • Continue ECG monitoring for at least 5-10 minutes
   • Measure blood pressure and heart rate
   • Document any symptoms or abnormalities 1, 2

3. Documentation:

   • Maximum heart rate achieved
   • Maximum blood pressure
   • Exercise duration
   • Reason for termination
   • ECG changes
   • Symptoms during test
   • Recovery data 2

Calibration and Maintenance

Treadmill Calibration

1. Ensure treadmill is on level surface using carpenter's level
2. Set elevation to 0% grade
3. Mark 2 points 50 cm apart along treadmill length
4. Elevate treadmill to 20% grade and measure distance of points to floor
5. Divide difference between heights by 20 (should equal 0.20 or 20%)
6. Check 5%, 10%, and 15% grade readings
7. Service treadmill after approximately 1000 hours of use 1

Speed Calibration

• Verify treadmill speed accuracy across commonly used protocols
• Speed should remain unchanged regardless of subject weight 1

Special Considerations

For Sedentary Patients

• Exercise testing should be performed cautiously in patients with sedentary lifestyles
• Consider starting with lower intensity protocols
• Monitor closely for signs of exercise intolerance 3

For Cardiac Rehabilitation

• Submaximal protocols may be appropriate
• Consider using Rating of Perceived Exertion (RPE) to regulate exercise intensity 4

For Peripheral Arterial Disease

• Graded protocols show higher reliability for absolute claudication distance
• Document initial claudication distance and absolute claudication distance 5

By following these guidelines, the treadmill test can provide valuable diagnostic and prognostic information while maintaining patient safety. The standard exercise treadmill test remains a cost-effective initial test for patients able to exercise adequately with normal resting ECG and no prior revascularization 6.