The Effects of Stress on Injury and Sickness Rates of Middle-distance and Distance Division III Athletes

Running training intentionally stresses the body to experience positive physiological changes, however, maladaptions such as suppressed immune function and growth hormone production may occur without adequate recovery. Male distance and middle distance athletes (n = 14) participated in this study. For 6 weeks, heart rate variability (HRV), resting heart rate (HRrest), perceived stress, and cortisol levels were assessed as indicators of recovery and stress. It was anticipated that indicators of physical stress, such as higher resting heart rates and lower heart rate variability, would correspond with greater perceived stress and higher occurrence of injury and sickness. Cortisol (n = 2, p = 0.449), heart rate variability (p = 0.59), and perceived stress (p = 0.31) did not significantly differ across the six weeks. Resting heart rate did show significant changes across time (p = 0.006, week 1: 46.2±9.3 bpm vs week 6: 53.1±12.1 bpm) and was also higher each week in those who experienced an injury or illness (n=6) versus those who did not (p = 0.026). During most weeks (2, 4, 5, and 6), HRV and HRrest were negatively correlated. Perceived stress did not correlate with either HRV or HRrest. These data could be useful as more measures can be implemented to predict and prevent injuries before they occur in the athletic realm. Future research should examine these variables over a full calendar year to examine all phases of the competitive running season.