Exercise ECG testing using different protocols in asymptomatic healthy young subjects.

Thirty four healthy young male subjects performed symptom limited exercise on Bruce protocol on treadmill machine. Hyperventilation induced labile repolarisation ST-T abnormalities were observed in 2 whereas exercise induced ST changes (upsloping ST depression in 4 and horizontal ST depression in 1) were observed in 5 additional candidates. Changes were unaccompanied by symptoms or signs and quickly reverted back to normal within 30 sec. of cessation of exercise and hence were 'probable false positives'. Sixty-eight age and sex matched volunteers (including former 34) when exercised on Master's stepper, failed to reveal any change probably due to the lack of continuous ECG monitoring device.