Determine the relationships between total hemoglobin mass (tHb-mass), h emoglobin (Hb), hematocrit (Hct) and competitive performance. The team of 35 elite endurance athletes (biathlon men [BM, N.=12] & women [BW, N.=10], long track speed-skating men [SM, N.=7] and women [SW, N.=6]) were examined before participate in seven different competitions (C1 through C7) during the 2012-2013 and 2013-2014 seasons. Total hemoglobin mass measurement and biochemical analysis were performed using carbon monoxide rebreathing technique 24 hours before the competition. In BM correlations were found between results of two 10-km sprint competitions and tHb-mass between C1 and C2 (r=-0.94 and r=-0.87). Correlations were also found between tHb-mass and performance in C3 individual races for BM (16.765 km, r=-0.88; and 10-km sprint, r=0.80) and BW (7.2 km, r=-0.79; and 10-km sprint, r=-0.81). In SM, a correlation was found between tHb-mass and performance (r=-0.83) in C5. In SM and SW correlations were seen between tHb-mass and performance (SM, 5,000-m; r=-0.80; SW, 3,000-m; r=-0.77) in C6. No correlation was found between performance and Hb or Hct in any group. The demonstration of significant and direct correlation between tHb-mass and competitive performance highlights the importance of tHb-mass in this context and may be relevant for coaches providing one more piece of information for training.

Although high altitude training has been increasingly popular among endurance athletes, the molecular and cellular bases of this adaptation remain poorly understood. We aimed to define the underlying physiological changes and screen for potential biomarkers of adaptation using transcriptional profiling of whole blood. Seven elite female speed skaters were profiled on the 18th day of high-altitude adaptation. Whole blood RNA-seq before and after an intense 1 h skating bout was used to measure gene expression changes associated with exercise. In order to identify the genes specifically regulated at high altitudes, we have leveraged the data from eight previously published microarray datasets studying blood expression changes after exercise at sea level. Using cell type-specific signatures, we were able to deconvolute changes of cell type abundance from individual gene expression changes. Among these were PHOSPHO1, with a known role in erythropoiesis, and MARC1 with a role in endogenic NO metabolism. We find that platelet and erythrocyte counts uniquely respond to altitude exercise, while changes in neutrophils represent a more generic marker of intense exercise. Publicly available data from both single cell atlases and exercise-related blood profiling dramatically increases the value of whole blood RNA-seq for the dynamic evaluation of physiological changes in an athlete’s body.

Purpose: Total hemoglobin mass (tHb_mass) and blood volume (BV) are important determinants of maximal oxygen uptake and endurance capacity. Higher-caliber endurance athletes usually possess higher tHb_mass and BV values. This study aimed to compare tHb_mass and BV among swimmers of diverse competitive calibers and distances. Methods: Thirty swimmers (16 female and 14 male) participated in the study: 3 were tier 5, world class (869 [59] FINA points); 15 were tier 4, elite/international (853 [38] points); and 12 were tier 3, highly trained/national (808 [35] points). They specialized in competition distances ranging from 200 m to open-water 10 km. Between February 2019 and February 2020, all swimmers had their tHb_mass and BV measured by carbon monoxide rebreathing 1 to 6 times and participated in multiple competitions and race events. Results: Relative tHb_mass and BV were not different (P > .05) between tiers among women or among men (pooled tHb_mass values 14.5 [0.5], 12.5 [1.5], 12.6 [2.3] g/kg for tier 5, tier 4, and tier 3, respectively). No differences were observed in relative tHb_mass (P = .215) and BV (P = .458) between pool and open-water swimmers or between 200-, 400-, and 1500-m specialists (P > .05). No significant correlations were found between the highest measured absolute or relative tHb_mass and BV and the highest FINA points scored over the follow-up period (R = −.42–.17, P = .256–.833), irrespective of competition distance. Conclusion: tHb_mass and BV values did not differ between swimmers of different calibers or among competition distances. Furthermore, these values did not correlate with FINA points, either in males or in females. The present results indicate that hematological characteristics may have a lesser impact on swimming performance than on land-based endurance sports.