Adjusted p values resulting from the multivariate linear regression showed statistically significant associations between distance 6 min walk test (m) and ferritin (p = 0.001), hepcidin (p = 0.001), and muscle iron content (p = 0.028), and between distance 6 min walk test (% predicted) and ferritin (p = 0.023), hepcidin (p = 0.025), and muscle iron content (p = 0.032) in the iron deficiency group. This evidence concerns the gene HAMP and Iron deficiency anemia.