Physiological and Psychological Stress Changes according to the Sleep Quality in Elite Shooters before and after Competition

OBJECTIVES This study investigates the differences in cortisol, a physiological stress indicator, and psychological anxiety and stress according to sleep quality in elite shooters and aims to provide basic information on how to reduce the perceived stress and improve the performance of elite shooters. METHODS The study participants were thirty-six national athletes and elite shooters registered with the Korea Shooting Federation, divided into two groups: the good sleep group (n = 17) and the poor sleep group (n = 19). Stress and anxiety were evaluated with a psychological questionnaire, and sleep quality and saliva cortisol were measured immediately before and after a shooting competition. RESULTS An independent t-test indicated that before the competition, intrinsic anxiety (p = 0.029) and stress (p = 0.015) were significantly lower in the good sleep group than in the poor sleep group. Correspondingly, another independent t-test indicated that before the competition, cortisol concentration (p < 0.01) was significantly lower in the good sleep group (0.43 ± 0.18 μg/ml) than in the poor sleep group (0.62 ± 0.20 μg/ ml). Ultimately, positive correlations were found between sleep quality and psychological factors (competitive anxiety (r = 0.338, p < 0.05), intrinsic anxiety (r = 0.419, p < 0.05), psychosocial anxiety (r = 0.348, p < 0.05), and stress (r = 0.507, p < 0.01), and negative correlations were found between sleep quality and match score (r = -0.482, p = 0.023). CONCLUSIONS Differences in cortisol, a physiological marker of stress, and in psychological anxiety and stress scores were evident between the good and poor sleep groups, and sleep quality was also correlated with the final competition outcomes in terms of match scores. Therefore, elite shooters need to improve their sleep quality to reduce stress and anxiety before competitions and improve their performance.