• Left main coronary stenosis
• Moderate stenotic valvular heart disease
• Electrolyte abnormalities
• Severe arterial hypertension at rest (SBP of > 200 mmHg and/or a DBP of > 110 mmHg)
• Tachydysrhythmia or bradydysrhythmia
• Hypertrophic cardiomyopathy
• Neuromotor, musculoskeletal, or rheumatoid disorders that are exacerbated by exercise
• High-degree AV block
• Ventricular aneurysm
• Uncontrolled metabolic disease (e.g., diabetes, thyrotoxicosis, or myxedema)'
• Chronic infectious disease (e.g., HIV)
• Mental or physical impairment leading to inability to exercise adequatel