Monitoring Of Ferritin And Vitamin D Levels In Female D1 Cross Country Runners

Female endurance runners are at a greater risk for developing iron deficient anemia and stress fractures compared to their male counterparts. Monitoring of hematological markers could help to prevent adverse events and declines in performance across the season. PURPOSE: To assess the effects of training on ferritin and vitamin D levels in DI women's cross country runners across a competitive season. METHODS: 16 D1 women’s cross-country runners (19.7 ± 1.3 yrs) were monitored during the season. Blood samples were taken at three time points (preseason, midseason, postseason) to assess runners basic metabolic panel, complete blood cell count, ferritin and vitamin D levels. Weekly training loads were monitored using GPS HR monitors and race performance data was also collected. RESULTS: Ferritin levels were broken down into three categories. Normal levels (NL, 40+ ng/mL), below the recommendations for endurance runners (BR, 20 to 39 ng/mL) and clinically significant (CS, below 20 ng/mL). During preseason, 4 runners fell into the CS category and another 9 were in the BR category. Based on these findings, nine of these athletes were placed on iron supplementation by the sports medical staff. At the midseason time point, an additional 6 athletes fell in the BR category and were placed on iron supplementation by the sports medical staff. By the end of the season, 15/16 runners were on iron supplementation. Despite iron supplementation, 11 out of 16 runners still fell into the BR category at the end of the season. None of the runners, however, were in the CS category at postseason. Overall, the mean ferritin level of the team did trend in a positive direction across the season (34.4 ± 19.0 to 39.5 ± 17.5 ng/mL). Vitamin D levels declined significantly across the season 41.05 ± 9.2 ng/mL to 35.5 ± 6.90 ng/mL (p < 0.05), with two athletes meeting the criteria for Vitamin D deficiency and requiring Vitamin D supplementation at the end of the season. CONCLUSIONS: During a competitive D1 women’s cross-country season 94% of runners fell below the recommended ferritin level for endurance runners and 12.5% of runners meet the requirement for vitamin D deficiency. Frequently monitoring of ferritin and vitamin D levels in female endurance runners should be done in order to decrease injury risk and optimize performance in this population.