Hematological, Hormonal and Fitness Indices in Youth Swimmers: Gender‐Related Comparisons

Abstract

This study objective was to evaluate gender differences in hematological, hormonal and fitness variables among youth swimmers and to explore relationships between erythrocyte indices and aerobic and anaerobic capacity. 137 girls and 171 boys participated in the study and were divided into three groups based on their training experience. Blood samples were obtained to determine red blood cell counts, hemoglobin concentration, hematocrit, and plasma erythropoietin and testosterone levels. VO2max was assessed using a submaximal cycle protocol. 76 girls and 102 boys also undertook a Wingate test to determine their peak anaerobic power. Boys had higher (p < 0.05) means than girls for all hematological variables except for erythropoietin and these variables demonstrated an increase with training in boys. The average VO2max in l∙min-1 and peak anaerobic power in watts were also higher in boys (2.91 ± 0.08 and 547 ± 28, respectively) than girls (2.25 ± 0.07 and 450 ± 26, respectively). Modest but significant (p < 0.05) correlations were found between VO2max and red blood cell counts (r = 0.252), hemoglobin concentration (r = 0.345), or hematocrit (r = 0.345) and between peak anaerobic power and red blood cell counts (r = 0.304), hemoglobin concentration (r = 0.319) or hematocrit (r = 0.351). This study revealed relatively lower yet age- and gender-appropriate hematological, hormonal and fitness indices in youth swimmers. The gender-related differences in erythrocyte indices seem unrelated to erythropoietin and may be explained by the higher testosterone levels seen in boys. Given their correlation to both aerobic and anaerobic capacity, erythrocyte indices may be used as part of talent identification for sports.

Gender Differences in Neuromuscular, Haematological and Urinary Responses during Padel Matches

“…Hematological differences appeared in men, obtaining higher values for RBC, hematocrit, and hemoglobin than women ( p < 0.001). These differences have also been previously reported for padel players [ 10 ], swimmers [ 53 ], and other sports [ 54 ]. Hormone differences and differences in muscle mass and physical condition between genders could influence hematological values [ 55 , 56 , 57 ].…”

Effect of a Padel Match on Biochemical and Haematological Parameters in Professional Players with Regard to Gender-Related Differences

“…Higher values were observed in men compared to women. These gender-related differences have been previously observed in other sports [32,33]. The difference in testosterone values between genders could explain the higher values observed in the men's group [34], not only related to protein synthesis and tissue growth, but also to erythropoiesis [35,36].…”

Intermittent Hypoxia Exposure Helps to Restore the Reduced Hemoglobin Concentration During Intense Exercise Training in Trained Swimmers

“…However, higher [Hb] usually leads to better performance (Calbet et al, 2006;Cai et al, 2019), as long as the hematocrit (Hct) is at the optimum range (Reinhart, 2016;Sitina et al, 2021). Actually, based on our long-term observation and other studies (Hasibeder et al, 1987;Zhao, 2003), the training load of athletes will usually be reduced once their [Hb] were 10% lower than their baselines.…”

“…There is literature supporting that a decrease in hemoglobin concentration ([Hb]) can be caused by acute or prolonged plasma volume (PV) expansion which can aid the athletes adapt to exercise training ( Kargotich et al, 1998 ). However, higher [Hb] usually leads to better performance ( Calbet et al, 2006 ; Cai et al, 2019 ), as long as the hematocrit (Hct) is at the optimum range ( Reinhart, 2016 ; Sitina et al, 2021 ). Actually, based on our long-term observation and other studies ( Hasibeder et al, 1987 ; Zhao, 2003 ), the training load of athletes will usually be reduced once their [Hb] were 10% lower than their baselines.…”