Goodrich JA, Frisco DJ, Kim S, Holliday M, Rueda M, Poddar S and Byrnes WC.
J Appl Physiol (1985). 2020 Sep 3.
Background: Hemoglobin mass (Hbmass) is important for athletes because it helps determine maximal aerobic power. This study examined how lean mass, iron deficiency (ID), and sex influence Hbmass in athletic and non-athletic groups.
Methods: NCAA Division I student athletes (21 males, 75 females, altitude: 1,625 meters) were recruited from six athletic teams; 14 male and 12 female full-time students (non-varsity athletes) served as controls. Hbmass, body composition, and iron homeostasis parameters, including ferritin, soluble transferrin receptor (sTfR), hepcidin, erythroferrone, and 10 inflammatory cytokines, were measured 2-4 times across a competitive/training season. ID was defined as ferritin <25 ng/mL.
Results: Hbmass was more closely related to lean mass (r2=0.90) than body mass (r2=0.69, p<0.01). Compared to females, males had 19.9% higher Hbmass relative to body mass (HbmassBM), but only 7.5% higher Hbmass relative to lean mass (HbmassLEAN; both p<0.001). Prevalence of ID was higher in females than males (47% vs. 9%, p<0.01), but did not vary between groups. HbmassLEAN was 5% lower in ID versus non-ID females; Hbmass relative to body mass (HbmassBM) was not different. ID was associated with lower hepcidin, elevated sTfR, and elevated erythroferrone, but not with differences in inflammatory cytokines.
Conclusion: Hbmass varied significantly between athletic groups and across sex, but the majority of these differences are explained by differences in lean mass. ID was common in females and was associated with lower HbmassLEAN and hepcidin, but not with differences in HbmassBM or inflammatory cytokines. Hbmass relative to lean mass seems advantageous when monitoring iron deficiency.