In addition, exercise capacity alone is a very strong prognostic indicator.118,119 The goal of exercise testing for suspected SIHD patients is 1) to achieve high levels of exercise (ie, maximal exertion), which in the setting of a negative ECG generally and reliably excludes obstructive CAD, or 2) to document the extent and severity of ECG changes and angina at a given workload (ie, demand ischemia) so as to predict the likelihood of underly- ing significant or severe CAD. Thus, candidates for exercise testing must possess sufficient functional capacity to attain maximal, volitional stress levels. Because there is high variability in age-predicted maximal heart rate among sub- jects of identical age,120 achieving 85% of age-predicted maximal heart rate might not indicate sufficient effort during exercise testing and should not be used as a criterion to terminate a stress test.121 Failure to reach peak heart rate (if beta blockers have been held as recommended) or to achieve adequate levels of exercise in the setting of a negative ECG is consistent with functional disability and results in an indeterminate estimation of CAD. Female-specific age- predicted maximal heart rate and functional capacity mea- surements are available.118,122 Standard treadmill protocols initiate exercise at 3.2 to 4.7 metabolic equivalents (METs) of work and increase by several METs every 2 to 3 minutes of exercise (eg, modified or standard Bruce protocol). Most activities of daily living require approximately 4 to 5 METs of physical work to perform. Thus, reported limitations in activities of daily living identify a patient who might be unable to perform maximal exercise. Gentler treadmill protocols, with incre- mental stages of 1 MET, or bicycle stress can help some patients achieve maximal exercise capacity. 