The following is a summary of “Determinants and reference values for blood volume and total hemoglobin mass in women and men,” published in the November 2023 issue of Hematology by Oberholzer et al.
Current Blood volume (BV) measurement per kg of BM may underestimate valid values in individuals with high-fat mass, necessitating alternative methods.
Researchers conducted a retrospective study investigating the effects of normalizing blood volume to lean body mass (LBM) on sex, age, and fitness-related differences.
They analyzed data from 263 women and 319 men (age: 10–93 years, body mass index: 14–41 kg/m 2) as well as 107 athletes who were assessed for blood volume (BV), hemoglobin mass (Hbmass), body composition, and cardiorespiratory fitness.
The results showed that BV/BM was 25% lower in women than in men (70.3 ± 11.3 and 80.3 ± 10.8 mL/kgBM, respectively), while BV/LBM was 6% higher in women (110.9 ± 12.5 and 105.3 ± 11.2 mL/kgLBM). Hbmass/BM was 34% lower in women compared to men (8.9 ± 1.4 and 11.5 ± 11.2 g/kgBM), but only 6% lower (14.0 ± 1.5 and 14.9 ± 1.5 g/kgLBM)/LBM. Age had no impact on BV. Athletes exhibited 17.2% higher BV/BM than non-athletes, decreasing to only 2.5% when normalized to LBM. Among the analyzed variables, LBM emerged as the strongest predictor for BV (RBM2 = .72, P<.001) and Hbmass (R2 = .81, P<.001).
Investigators concluded that Hbmass/LBM may serve as a valuable clinical parameter for normalizing blood volume assessment, mainly when CO rebreathing is used.