Age-Matched Comparison of Elite and Non-elite Military Performers during Free Living and Intense Operational Stress

BACKGROUND: A useful approach to quantifying factors which influence human performance involves the classification and comparison of so-called “elite” and “non-elite” performers. OBJECTIVE: In this pilot study, we classified 6 graduates of the Basic Underwater Demolition/SEAL training program as elite and compared them to 6 age-matched non-elite military personnel on key aspects of physiological and psychological function during free living and in response to intense military stress. METHODS: Participants completed measures of perceived stress and anger during daily living. Diurnal variation in heart rate (a marker of parasympathetic cardiac control) was measured via ambulatory holter monitoring. Participants were then followed during stressful survival training, where salivary cortisol was sampled during mock-captivity and acute stress responses were examined via self-report. RESULTS: Elite performers reported less perceived stress (p = .07) during daily living. Group differences in diurnal cardiac function were also observed, whereas elite performers demonstrated more substantial nocturnal heart rate dipping (29% versus 21%; p = .08). Although elite performers produced nearly identical cortisol responses to an overt high-stress encounter during mockcaptivity, they generated much lower cortisol responses in the absence of overt challenge (p = .003) – a phenomenon we termed “selectivity.” Finally, elite performers reported fewer subjective stress responses to mock-captivity (p = .08) than their non-elite counterparts. CONCLUSIONS: Elite and non-elite military performers differ across several criteria both during free living and in response to intense stress. Of particular importance, elite performers demonstrate greater “selectivity” in response to overt stressors – a possible marker of adaptability or resilience. Results are discussed within the evolutionary paradigm of “predator imminence.” These findings have broad implications for the identification, selection, and training of elite performers in high-stress occupations. Taylor et al: Elite Non-elite comparison 3