This study investigated 4 research questions addressing exercise capabilities and psychological characteristics of middle-age (30 to 50 years) male runners. Subjects provided an extensive running history, completed the Multidimensional Anger Inventory, completed the Myers-Briggs Type Indicator, and performed a treadmill running test to volitional exhaustion. Another aspect of the study compared anticipatory and posttest reactions to the treadmill test experience to actual test results. The findings suggest that these runners have common personality profiles, that long-term involvement in running and training is associated with a positive sense of self, and that lifelong aerobic exercise is associated with high cardiovascular fitness. Although the research design does not permit causal or predictive conclusions, the study provides valuable additional baseline information for physicians and fitness professionals who serve middle aged male runners.