Does Hemoglobin Mass Increase from Age 16 to 21 and 28 in Elite Endurance Athletes?

STEINER, T., and J. P. WEHRLIN. Does Hemoglobin Mass Increase from Age 16 to 21 and 28 in Elite Endurance Athletes? Med. Sci. Sports Exerc., Vol. 43, No. 9, pp. 1735-1743, 2011. Purpose: It is unclear if hemoglobin mass (Hb(mass)) and red cell volume (RCV) increase in endurance athletes with several years of endurance training from adolescence to adulthood. The aim of this study, therefore, was to determine with a controlled cross-sectional approach whether endurance athletes at the ages of 16, 21, and 28 yr are characterized by different Hb(mass), RCV, plasma volume (PV), and blood volume (BV). Methods: BV parameters (CO rebreathing), (V) over dotO(2max) and other blood, iron, training, and anthropometric parameters were measured in three endurance athlete groups AG16 (n = 14), AG21 (n = 14), and AG28 (n = 16) as well as in three age-matched control groups (<2 h endurance training per week): CG16 (n = 16), CG21 (n = 15), and CG28 (n = 16). Results: In AG16, body weight-related Hb(mass) (12.4 +/- 0.7 g.kg(-1)), RCV, BV, and (V) over dotO(2max) (66.1 +/- 3.8 mL.kg(-1).min(-1)) were lower (P < 0.001) than those in AG21 (14.2 +/- 1.1 g.kg(-1), 72.9 +/- 3.6 mL.kg(-1).min(-1)) and AG28 (14.6 +/- 1.1 g.kg(-1), 73.4 +/- 6.0 mL.kg(-1).min(-1)). Results for these parameters did not differ between AG21 and AG28 and among the control groups. (V) over dotO(2max), PV, and BV were higher for AG16 than for CG16 (12.0 +/- 1.0 g.kg(-1), 58.9 +/- 5.0 mL.kg(-1).min(-1)) but not Hb(mass) and RCV. Conclusions: Our results suggest that endurance training has major effects on Hb(mass) and RCV from ages 16 to 21 yr, although there is no further increase from ages 21 to 28 yr in top endurance athletes. On the basis of our findings, an early detection of the aptitude for endurance sports at age 16 yr, solely based on levels of Hb(mass), does not seem to be possible.