Plasma volume reduction and hematological fluctuations in high‐level athletes after an increased training load

Abstract

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 (proANP) 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 proANP only correlated weakly (R <.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 proANP could not explain PV fluctuations.

Effects of hydration status during heat acclimation on plasma volume and performance

“…Similar to our findings, in a crossover design Keiser et al also implemented variable training loads set to elicit the same relative cardiac strain in both their hot and cool training conditions and also found that none of the heat adaptations (eg, increased PV) correlated to changes in exercise performance. Indeed, although not always shown, increased training load or multi‐day competition in already hypervolemic elite endurance athletes (international level cyclists) has been shown to augment PV by 5%‐20% in as little as 6‐7 days regardless of the heat load . Importantly, the current study's outcomes, in combination with training effects on PV, suggest that many of the previously published HA studies without an exercise control group in mild/cool conditions matched for relative cardiac work stress, may be showing outcomes that are due to both exercise stress, and metabolic heat.…”

“…Indeed, although not always shown, 34 increased training load or multi-day competition in already hypervolemic elite endurance athletes (international level cyclists) has been shown to augment PV by 5%-20% in as little as 6-7 days regardless of the heat load. [35][36][37] Importantly, the current study's outcomes, in combination with training effects on PV, suggest that many of the previously published HA studies without an exercise control group in mild/cool conditions matched for relative cardiac work stress, may be showing outcomes that are due to both exercise stress, and metabolic heat. In our study, despite a 30% greater total AUC heat stress in the EUH and DEH groups, as well as a post-HA reduction in resting T c (a classic marker of HA) compared to CON, there was no further increase in PV or performance outcomes in the heat.…”

The athlete's hematological response to hypoxia: A meta‐analysis on the influence of altitude exposure on key biomarkers of erythropoiesis

“…A number of possible factors may contribute to these extreme delta values, beyond the influence of altitude. First, training load or fatigue may be a factor, although this was controlled in most studies, athletes may still be tempted to train beyond their normal volumes in the performance testing setting . Further, hematological assessments performed on a rest‐day may influence the result .…”

Fluctuations in hematological athlete biological passport biomarkers in relation to the menstrual cycle

“…7 In addition to blood doping, several factors may affect the hematological profile, for example, altitude exposure, physical exercise, time of the day and year, and hydration status. [8][9][10][11][12] An increased knowledge of how these and other confounders interact with the hematological passport will further improve the interpretation of ABP results.…”