Quantification of testosterone‐dependent erythropoiesis during male puberty

Abstract

The amount of haemoglobin during puberty is related to endurance performance in adulthood. During male puberty, testosterone stimulates erythropoiesis and could therefore be used as a marker for later endurance performance. This cross-sectional study aimed to determine the relationship between serum testosterone concentration and haemoglobin mass (Hbmass) in both male and female children and adolescents and to evaluate the possible influences of altitude and training. Three-hundred and thirteen differentially trained boys and girls aged from 9 to 18 years and living at altitudes of 1000 and 2600 m above sea level entered the study. The stage of sexual maturation was determined according to the classification of Tanner. Testosterone was measured by ELISA. Hbmass was determined by CO-rebreathing. Haemoglobin concentration did not change during maturation in girls and was 11% higher during puberty in boys, while Hbmass was elevated by 33% in Tanner stage V compared to stage II in girls (498 ± 77 vs. 373 ± 88 g) and by 95% in boys (832 ± 143 vs. 428 ± 95 g). This difference can most likely be attributed to indirect testosterone influences through an increase in lean body mass (LBM) and to direct testosterone effects on erythropoiesis, which increase the Hbmass by ∼65 g per 1 ng/ml. Altitude and training statuses were not associated with testosterone, but with an increase in Hbmass (altitude by 1.1 g/kg LBM, training by 0.8 g/kg LBM). Changes in Hbmass are closely related to testosterone levels during male puberty. Further studies will show whether testosterone and Hbmass during childhood and adolescence can be used as diagnostic tools for endurance talents.

Hemoglobin Mass, Blood Volume and VO2max of Trained and Untrained Children and Adolescents Living at Different Altitudes

“…Finally, possible differences in terms of hematological and performance parameters between children and adolescents in different sports disciplines at different altitudes should be pointed out. In a first, recently published step, we showed the normal course of the increase in Hbmass during puberty in male and female adolescents and the influence of the increasing testosterone concentration in boys (Mancera-Soto et al, 2021). The work presented here represents the main part of the study and, in addition to the normal development of Hbmass, BV and VO 2 max in children and adolescents, describes the influence of training status and different altitudes on the above parameters and their interactions.…”

“…In total, 475 healthy children and adolescents (girls n = 217, boys n = 258; untrained group n = 171, endurance trained group n = 304) living at two different altitudes (~1,000 m, n = 204, ~2,600 m, n = 271) and aged from 9 to 18 years old participated in the study. Data on Hbmass and BV in relation to serum testosterone and erythropoietin concentrations were already determined from 313 participants in a recent publication (Mancera-Soto et al, 2021). Hematological data were recorded for all 475 children, and maximum oxygen uptake (VO 2 max) was determined in 404 participants.…”

“…The first aim of this part of the project was, therefore, using a cross-sectional design with a large number of participants, to show the possible relationships of Hbmass and BV with endurance training activity and the place of residence. As in the first part of this project, a small, general effect of altitude and training on Hbmass was shown (Mancera-Soto et al, 2021); in this part, we increased the number of participants and focused on the training and altitude effects occurring selectively during pre/early puberty, mid-puberty and late puberty.…”

Heterogeneity of Hematological Response to Hypoxia and Short-Term or Medium-Term Bed Rest

“…The introduction of testosterone causes a rightward shift in the EPO-Hb relationship curve as well as a new physiological "set point" (Bachman et al, 2014). Mancera-Soto et al (2021), claims that during the most sensible phase of puberty, an increase in testosterone plasma of 1 ng/ml is correlated to an increase in hemoglobin mass of ~65 g. The effects of testosterone on individual variability in men compared to women; however, is currently unknown and would require further examination. Furthermore, Goodrich et al (2020) demonstrated that variations in hemoglobin mass across groups of varying athleticism and sex were more closely related to lean body mass than whole body mass.…”

Puberty, more important for cardiovascular adaptations than endurance training?

“…Although they raise the challenge of establishing causality from cross‐sectional studies in their limitation section, we are surprised they still conclude that endurance training yields an additional effect on cardiovascular changes during puberty over those driven by growth and maturation alone. It is undisputed that puberty exerts significant physiological changes on the growing child, mainly driven by altered circulating hormones that stimulate increased lean body mass and changes in haemoglobin mass (Hb mass ) and blood volume (Baxter‐Jones, 2017; Landgraff & Hallén, 2020; Landgraff et al., 2021; Mancera‐Soto et al., 2021; Rogol et al., 2002). If and to what extent endurance training causes additional haematological and cardiovascular changes beyond those driven naturally by growth and maturation is still uncertain and can only be assessed convincingly by randomized controlled trials or longitudinal study designs.…”