Effects of sleep, resilience, and hardiness on the psychological stress response of Japanese university students over the previous two to three days.

The present study examined the extent to which overall sleep quality, resilience, and hardiness affect stress responses over the previous two to three days among Japanese university students. An online, anonymous questionnaire was administered, collecting demographic data and responses to the Japanese versions of the Pittsburgh Sleep Quality Index (PSQI), Resilience Scale for Students (RS-S), Hardiness Scale (HS), and Stress Response Scale-18 (SRS-18) scales. Four hierarchical linear multiple regression analyses were conducted using the SRS-18 total score and its subscales (Depression-Anxiety, Irritability-Anger, and Helplessness scores) as objective variables. Explanatory variables were the Global RS-S score, RS-S score, and HS score, with sex, age, and the survey period as confounding variables. In the analysis with the SRS-18 total score as the objective variable, the PSQI score (β = 0.28) and RS-S score (β = -0.28) both showed significant effects, whereas the HS score (β = -0.11) did not. Results remained stable after controlling for confounders. Similar results were obtained for the Depression-Anxiety and Irritability-Anger scores, but not for the Irritability-Anger score: PSQI (β = 0.18), RS-S (β = -0.19), HS (β = -0.06). Overall sleep quality affected short-term stress responses to a similar degree as resilience, particularly regarding Depression-Anxiety and Irritability-Anger.