Mineral Density Levels in Male and Female Collegiate Cross Country Runners: Is there Reason for Concern?

Abstract

Introduction: The results of several recent studies have questioned the consequences of high levels of running on bone mineral density (BMD). Elite endurance athletes experience high physiological stress which may negatively impact bone health. Thus, the purpose of this study was to examine the change in BMD in male and female Division I collegiate runners during a competitive Cross Country (CC) season. Methods: T wenty-three (1 1 male and 12 female) Division I collegiate CC runners (ages 18-22 year) were recruited for this study. Total/regional BMD and body composition was determined using dual x-ray absorptiometry. Caloric intake and running mileage was obtained from self-reported diet and training logs. All measures were performed prior to the start (pre) and immediately following (post) a three month collegiate CC season. Results: Males did not demonstrate any significant changes in body composition from pre-post CC whereas females had a significant increase (2.7 ± 1.7 lbs or 2.1%) in total mass, with non-significant increases in fat free and fat mass. From pre- post CC, males did not have any significant changes in bone density whereas females had a statistically significant decrease in bone density of lumbar vertebrae. While no other changes in total or regional BMD were observed, ~ 50% of the both male and female athletes tested in this study had total BMD lower than the age-based reference value. Conclusion: The results of this study suggest that a single competitive CC season can result in a decrease in the lumbar spine BMD in female collegiate distance runners. Moreover, this study revealed that a large percentage (~ 50%) of both male and female distance runners had lower than age-adjusted normal BMD level, raising concerns about long-term bone health in these athletes. Verification of these findings in a larger more diverse population of young athletes is warranted to determine the long term consequences of distance running on bone health.