This study investigated the psychobiological and pacing characteristics of the 1.5 mile run. Sixty-six males (18-27 years) performed the run, and were monitored for ratings of perceived exertion, heart rate and split times. The perceived exertion values increased in a near-linear fashion inconsistent with other measures, and thus are not considered a supportable indicator of physiological performance during the run. Pace was characterized by an initial sprint that slowed to a near-steady pace and concluded with a final sprint. The initial and final sprints were most highly related to the variance of performance time. Initially, heart rate accelerated greatly. This acceleration slowed, ending in near-maximum heart rates. The data suggested that performance may rely heavily upon anaerobic mechanisms, and that variance in previously reported correlational analyses of VO2max and 1.5 mile run performance times may be somewhat due to anaerobic mechanisms.