Rapid body mass loss affects erythropoiesis and hemolysis but does not impair aerobic performance in combat athletes

Rapid body mass loss (RBML) before competition was found to decrease hemoglobin mass (Hbmass) in elite boxers. This study aimed to investigate the underlying mechanisms of this observation. Fourteen well‐trained combat athletes who reduced body mass before competitions (weight loss group, WLG) and 14 combat athletes who did not practice RBML (control group, CON) were tested during an ordinary training period (t‐1), 1–2 days before an official competition (after 5–7 days RBML in WLG, t‐2), and after a post‐competition period (t‐3). In WLG, body mass (−5.5%, range: 2.9–6.8 kg) and Hbmass (−4.1%) were significantly (P