SUMMARY Sixteen diabetic males, 32-60 years old (mean 48.7±8.9 years), without clinical or electrocardiographic evidenceof heart disease and 12 normal volunteers, mean age 48.9±8.8 years, participated in maximal exercise testing combined with thallium-201 myocardial scintigraphy. A motorized treadmill was used with the Bruce protocol. A standard 12-lead ECG and systolic blood pressures were recorded every minute during exercise and forat least 8 minutes in the postexercise period. Echocardiograms were obtained at rest for chamber dimensions and myocardial function.

At maximal stress the heart rate attained by the normal controls was higher (174.5±17.4 beats/min) than that of the diabetic males (163.1±9.9 beats/min)(p< 0.05). Although the maximal systolic blood pressure for both groups was comparable (215.9±32.5 mm Hg for the diabetics vs 209.6±21.6 mm Hg for the normal controls), maximal systolic blood pressures> 210 mm Hg occurred in only three of 12 normal subjects (25%) but was noted in nine of 16 diabetics (56.2%).