The influence of exercise and circadian rhythm of haemoglobin concentration associated changes in plasma volume on the biological passport

Abstract

In the fight against doping in sports, indirect detection methods using Hb and Hct are starting to play a more and more important role. The goal of this investigation was to quantify the changes in PV during a 2 week study of endurance exercise simulating a cycling stage race and to test for PV changes relative to the circadian rhythm of the athlete. 15 endurance trained triathletes and cyclists performed a standardised 3 day taper (no exercise), followed by a 9 day cycling stage race simulation. Hb showed a mean increase of 4% during the 3 day taper period which was caused by a reduction in PV. During the exercise phase Hb dropped by 1.5 g/dl or 11%, which relates to an average expansion of PV by 0.6 l or 16%. The fluctuations in morning PV showed a wide inter-subject variability. The smallest change was 493 ml (10%), which was accompanied with a drop in Hb from 14.8 g/dl to 13.7 g/dl. The largest increase was 1277 ml (or 25%). The corresponding Hb values for this subject dropped from 15.8 g/dl to 13.1 g/dl (figure 2). The Hb concentration of the morning and evening samples showed a mean difference of approximately 0.6 g/dl or 3.7%, which was observed both during the taper (without exercise) and stage race phases. This study showed that exercise induced changes of PV in healthy trained endurance athletes can be up to 1277 ml or 25% when tested at the same time of the day. This fact needs to be considered in the interpretation of blood profiles as this value might even be higher if the test was to be performed at different times of the day. In our study we were able to demonstrate that the circadian rhythm of Hb concentration remains stable even under maximal PV expansion and reaction to exercise. This finding could be implemented in the athlete biological passport model to help reduce the variation of biological markers.

Validation of a blood marker for plasma volume in endurance athletes during a live‐high train‐low altitude training camp

“…Beidleman et al also described variability in the individual response, where the reported standard error for [Hb] is large for the impact of the time spent at altitude (Table 3 of Beidleman et al), suggesting considerable inter‐individual variability at altitude. Additionally, the intermittent nature of the LHTL protocol, differences in training load, and the non‐standardisation of blood collection times may have impacted the variable volumetric response reported here. Due to scheduling restrictions in the current study, the timing of the blood withdrawals and training programmes were not standardised.…”

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

“…Further, hematological assessments performed on a rest‐day may influence the result . Timing of the blood withdrawal will also be influenced by the circadian rhythm of [Hb] and retic%, however, within this meta‐analysis, the timing of the blood withdrawals varied between studies so no definitive conclusions can be made. Differences between studies in temperature and seasonal variation are not considered here but can influence the results .…”

99mTc‐labelled human serum albumin cannot replace 125I‐labelled human serum albumin to determine plasma volume in patients with liver disease

“…Child Class A and B patients were younger than patients without liver disease, and all patients with cirrhosis were hyperdynamic with increased cardiac index, as previously reported Møller & Henriksen, 2010). This is, however, considered to be of minor importance, as the size of cardiac output does not influence the determination of PV, but only the mixing time for the indicators (Peters & Meyers, 2003;Convertino, 2007;Voss et al, 2011). It has recently been reported that the 99m Tc-HSA indicator in normal subjects leaves the plasma volume somewhat faster compared with 125 I-HSA (Bonfils et al, 2012), but not with a magnitude, as indicated by the present results.…”