Effect of Endurance Training on Hemoglobin Mass and V˙O(2max) in Male Adolescent Athletes

PURPOSE: It is unknown, whether endurance training stimulates hemoglobin mass (Hb(mass)) and maximal oxygen uptake (V˙O(2max)) increases during late adolescence. Therefore, this study assessed the influence of endurance training on Hb(mass), blood volume parameters, and V˙O(2max) in endurance athletes and control subjects from age 16 to 19 yr. METHODS: Hemoglobin mass, blood volume parameters, V˙O(2max) and anthropometric parameters were measured in male elite endurance athletes from age 16 to 19 yr in 6-month intervals (n = 10), as well as in age-matched male controls (n = 12). RESULTS: Neither the level of Hb(mass) per lean body mass (LBM) (P = 0.80) nor the development of Hb(mass) during the 3 yr (P = 0.97) differed between athletes and controls. Hb(mass) at age 16 yr was 13.24 ± 0.89 g·kg(−1) LBM and increased by 0.74 ± 0.58 g·kg(−1) LBM (P < 0.01) from age 16 to 19 yr. There was a high correlation between Hb(mass) at age 16 and 19 yr (r = 0.77; P < 0.001). Plasma volume, blood volume, and V˙O(2max) were higher in athletes compared to controls (P < 0.05). Blood volume and V˙O(2max) increased with age (P < 0.01, similarly in both groups). CONCLUSIONS: Endurance training volumes do not explain individual differences in Hb(mass) levels nor Hb(mass) and V˙O(2max) development in the age period from 16 to 19 yr. The higher V˙O(2max) levels of athletes may be partially explained by training-induced higher plasma and blood volumes, as well as other training adaptations. Since Hb(mass) at age 16 yr varies substantially and the development of Hb(mass) in late adolescence is comparably small and not influenced by endurance training, Hb(mass) at age 16 yr is an important predictor for Hb(mass) at adult age and possibly for the aptitude for high-level endurance performance.