Psychiatric Diagnosis is Associated with Pacing Divergence Under Fatigue in Boston Marathon Performance

INTRODUCTION: Endurance running depends on sustaining pace as physiological strain accumulates, yet fatigue-related performance variability remains incompletely characterized. Although many factors contribute to this variability, the role of psychiatric diagnosis has not been examined. Given that psychiatric diagnoses are associated with altered stress responses, this represents a potentially important but unexplored source of performance heterogeneity. This study tested whether lifetime psychiatric diagnosis was associated with marathon performance. METHODS: Prior to the Boston Marathon, 450 runners completed a survey assessing psychiatric diagnostic history, demographics, training, injury status, prior marathon experience and record time, psychological traits, and current anxiety symptom severity. Official race times were obtained from race records. Goal realization was indexed as the percentage of anticipated finish time achieved. Group comparisons and Bonferroni-corrected multiple regressions assessed associations between psychiatric diagnosis and performance. Split-level performance trajectories were analyzed using linear mixed-effects models. RESULTS: Sixteen percent (16.7%) of runners reported a lifetime psychiatric diagnosis. Runners with a psychiatric diagnosis had slower finish times (M=4:14:11 vs. 3:53:59; p<0.001) and poorer goal realization (91.4% vs. 93.6%; p=0.044) than those without; although the latter was dependent on covariate adjustment. Across all covariate-adjusted models, psychiatric diagnosis remained a significant predictor of both slower finish time (β=1018.04 to 1084.17, all p<0.001) and poorer goal realization (β=-2.82 to -3.27, all p≤0.002), indicating a consistent effect independent of baseline fitness, training, and demographic factors. Split-level analyses revealed progressive pacing divergence across race distance, with runners with a psychiatric diagnosis slowing down and accumulating ~25 additional seconds/kilometer. CONCLUSIONS: Lifetime psychiatric diagnosis was associated with slower marathon performance and progressive pacing inefficiency under fatigue. Psychiatric diagnosis-associated susceptibility therefore represents a previously unrecognized contributor to individual differences in endurance running performance.