Predicting Psychophysiological Stress in Collegiate Cross Country Skiers Using Wrist-Worn Sleep Monitors and Standardized Surveys

Abstract

Chronic stress exposure, whether cognitive or physiological in origin (psychophysiological), can contribute to long term negative health outcomes in athletes and non-athletes (e.g., depression, substance abuse, eating disorders, higher rates of sickness and injury). College student-athletes are especially susceptible to the influence of chronic stress because of the relatively unique combination of cognitive stressors (financial, social, academic), physiological stressors (training, competition), as well as limited stress management skills. PURPOSE: The purpose of this study was to pilot the development of an instrument for predicting the underlying determinants of psychophysiological stress in collegiate cross country (XC) skiers. METHODS: Fifteen collegiate XC skiers (10 women, 5 men) completed a series of measures during two separate weeks in September and October. During each week, an accelerometry-based activity monitor, worn on the wrist at night, monitored total sleep time (TST) and sleep efficiency (SE). Responses to standardized surveys were used to compute measures of daytime sleepiness (DaySLP), a sleep quality index (SQI), as well as total weekly training load (TL) from self-reported training logs. Each of these variables, along with gender (0 = women, 1 = men), were then used as potential predictors of College Student-Athlete Life Stress (CSALS), a 24-item, 8-factor, instrument validated to quantify potential stressors of college student-athletes. The CSALS prediction model was generated using standard step forward multiple linear regression (P to enter/exit = 0.05) with alpha = 0.05. RESULTS: Four independent variables (gender, SE, DaySLP, and SQI) significantly explained 21%, 25.6%, 24.6%, and 8.7% of the variance in CSALS, respectively, whereas neither TST nor TL contributed to the final model: CSALS = 504.0 -16.3xGender + 1.86xSQI + 1.48xDaySLP - 5.21xSE (R2=0.80, P<0.001). CONCLUSIONS: Measures of nighttime sleep quality (measured and perceived), daytime sleepiness, and gender were highly predictive of psychophysiological stress (80% variance explained) in collegiate XC skiers. Future studies may be able to generalize these results to other collegiate sports so that coaches and athletes can better understand the development of psychophysiological stress.