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The time course of plasma volume ( PV) reduction following an increased training load period is unknown and was investigated. The accompanying fluctuations in [Hb] and OFF-hr score were analyzed in the Athlete Biological Passport. Further, whether fluctuations in plasma albumin, soluble transferrin receptors ( sTfR), and pro-atrial natriuretic peptide (pro ANP) concentrations correlate with PV fluctuations was investigated. Eleven high-level competitive cyclists were investigated for 3 weeks. After initial measurements in week 1, training load was increased ~250% in week 2 followed by a reversion to baseline training load in week 3. PV and hematological variables were determined frequently during all weeks. The higher training load in week 2 increased ( P<.001) PV 10%, while [Hb] and OFF-hr score decreased ~6% ( P<.01) and ~16% ( P<.001), respectively. PV and [Hb] returned to baseline within 2 and 4 days after week 2, respectively, while OFF-hr score remained reduced for 6 days. Further, one and three atypical blood profiles of the ABP occurred during weeks 2 and 3, respectively. Individual changes in albumin, sTfR, and pro ANP only correlated weakly ( R2<.20) with PV fluctuations. In conclusion, PV and [Hb] fluctuations caused by an elevated training load period were reverted within 2 and 4 days after returning to baseline training load, respectively, while OFF-hr remained altered for 6 days. Furthermore, some atypical blood profiles were induced during and subsequent to the increased training load, demonstrating the importance of knowledge on naturally occurring hematological fluctuations. Finally, concentrations of albumin, sTfR, and pro ANP could not explain PV fluctuations. [ABSTRACT FROM AUTHOR]

Anecdotal evidence suggests that athletes hyperhydrate to mask prohibited substances in urine and potentially counteract suspicious fluctuations in blood parameters in the athlete biological passport ( ABP). It is examined if acute hyperhydration changes parameters included in the ABP. Twenty subjects received recombinant human erythropoietin ( rhEPO) for 3 weeks. After 10 days of rhEPO washout, 10 subjects ingested normal amount of water (∼ 270 mL), whereas the remaining 10 ingested a 1000 mL bolus of water. Blood variables were measured 20, 40, 60, and 80 min after ingestion. Three days later, the subjects were crossed-over with regard to water ingestion and the procedure was repeated. OFF-hr was reduced by ∼ 4%, ∼ 3%, and ∼ 2% at 40, 60, and 80 min, respectively, after drinking 1000 mL of water, compared with normal water ingestion ( P < 0.05). Forty percent of the subjects were identified with atypical blood profiles (99% specificity level) before drinking 1000 mL of water, whereas 11% ( n = 18), 10% and 11% ( n = 18) were identified 40, 60, and 80 min, respectively, after ingestion. This was different ( P < 0.05) compared with normal water intake, where 45% of the subjects were identified before ingestion, and 54% ( n = 19), 45%, and 47% ( n = 19) were identified 40, 60, and 80 min, respectively, after ingestion. In conclusion, acute hyperhydration reduces ABP OFF-hr and reduces ABP sensitivity. [ABSTRACT FROM AUTHOR]