Laura A. Garvican

Time course of the hemoglobin mass response to natural altitude training in elite endurance cyclists.

To determine the time course of hemoglobin mass (Hbmass) to natural altitude training, Hbmass, erythropoietin [EPO], reticulocytes, ferritin and soluble transferrin receptor (sTfR) were measured in 13 elite cyclists during, and 10 days after, 3 weeks of sea level (n=5) or altitude (n=8, 2760 m) training. Mean Hbmass, with a typical error of ∼2%, increased during the first 11 days at altitude (mean ± standard deviation 2.9 ± 2.0%) and was 3.5 ± 2.5% higher than baseline after 19 days. [EPO] increased 64.2 ± 18.8% after 2 nights at altitude but was not different from baseline after 12 nights. Hbmass and [EPO] did not increase in sea level. Reticulocytes (%) were slightly elevated in altitude at Days 5 and 12 (18.9 ± 17.7% and 20.4 ± 25.3%), sTfR was elevated at Day 12 (18.9 ± 15.0%), but both returned to baseline by Day 20. Hbmass and [EPO] decreased on descent to sea level while ferritin increased. The mean increase in Hbmass observed after 11 days (∼300 h) of altitude training was beyond the measurement error and consitent with the mean increase after 300 h of simulated live high:train low altitude. Our results suggest that in elite cyclists, Hbmass increases progressively with 3 weeks of natural altitude exposure, with greater increases expected as exposure persists.

Carbon monoxide uptake kinetics of arterial, venous and capillary blood during CO rebreathing

The uptake and distribution of CO throughout the circulatory system during two different methods of CO rebreathing (2 min ‘Schmidt’ and 40 min ‘Burge’ methods) were determined in nine healthy volunteers. Specifically, the impact of (i) differences in circulatory mixing time (tmix), (ii) CO diffusion to myoglobin (Mb) and (iii) CO wash‐out was assessed on calculated haemoglobin mass (Hbmass). Arterial (a), muscle venous (vm) and capillary samples (c) were obtained simultaneously at 0, 1, 2, 3.5, 5, 7.5, 10, 12.5, 15, 20, 30 and 40 min for determination of carboxyhaemoglobin (HbCO). Carbon monoxide wash‐out was measured from expired air following rebreathing. The rate of CO diffusion to Mb was calculated using the change in HbCO after tmix, and the rate of CO wash‐out. In both methods, HbCOa and HbCOc followed a near‐identical time course, peaking within the first 2 min and decreasing thereafter. The HbCOvm increased slowly and was significantly lower at 1, 2 and 3.5 min in both methods (P < 0.01). The HbCOa peaked significantly higher in the Schmidt method (P= 0.03). Circulatory mixing had occurred by 10 min in most but not all subjects. The rate of CO wash‐out was 0.25 ± 0.13 ml min−1 in the Schmidt and 0.25 ± 0.16 ml min−1 in the Burge method. The rate of CO diffusion to Mb was 0.22 ± 0.11 and 0.16 ± 0.13 ml min−1 (P= 0.63) in Schmidt and Burge methods, respectively. Inhalation of a CO bolus during the Schmidt method results in faster HbCOa uptake but does not greatly shorten tmix or influence rates of CO wash‐out and flux to Mb. The calculated Hbmass depends substantially on the plateau level of HbCO; therefore, it is paramount to ensure HbCO is mixed completely prior to blood sampling, as well as accounting for potential within‐subject alterations of CO exhalation and CO flux to Mb.

Standardising analysis of carbon monoxide rebreathing for application in anti-doping

Determination of total haemoglobin mass (Hbmass) via carbon monoxide (CO) depends critically on repeatable measurement of percent carboxyhaemoglobin (%HbCO) in blood with a hemoximeter. The main aim of this study was to determine, for an OSM3 hemoximeter, the number of replicate measures as well as the theoretical change in percent carboxyhaemoglobin required to yield a random error of analysis (Analyser Error) of ≤1%. Before and after inhalation of CO, nine participants provided a total of 576 blood samples that were each analysed five times for percent carboxyhaemoglobin on one of three OSM3 hemoximeters; with approximately one-third of blood samples analysed on each OSM3. The Analyser Error was calculated for the first two (duplicate), first three (triplicate) and first four (quadruplicate) measures on each OSM3, as well as for all five measures (quintuplicates). Two methods of CO-rebreathing, a 2-min and 10-min procedure, were evaluated for Analyser Error. For duplicate analyses of blood, the Analyser Error for the 2-min method was 3.7, 4.0 and 5.0% for the three OSM3s when the percent carboxyhaemoglobin increased by two above resting values. With quintuplicate analyses of blood, the corresponding errors reduced to .8, .9 and 1.0% for the 2-min method when the percent carboxyhaemoglobin increased by 5.5 above resting values. In summary, to minimise the Analyser Error to ∼≤1% on an OSM3 hemoximeter, researchers should make ≥5 replicates of percent carboxyhaemoglobin and the volume of CO administered should be sufficient increase percent carboxyhaemoglobin by ≥5.5 above baseline levels.

Stability of hemoglobin mass during a 6-day UCI ProTour cycling race.

Objective:Blood doping in endurance sport is a growing problem. The purpose of this study was to determine the reliability of total hemoglobin mass (Hbmass) measurement in the field and to establish the variability of Hbmass during a cycling race, to assess its viability as an additional antidoping detection parameter. Design:Control-matched longitudinal study. Setting:International Cycling Unions (UCI) ProTour stage race. Participants:Six professional cyclists and 5 recreationally active controls. Interventions:Seventy-two Hbmass tests using the optimized carbon monoxide rebreathing method were performed over 7 consecutive days, before and throughout the tour. Fasted venous blood was obtained for measurement of hematocrit (Hct) and hemoglobin concentration [Hb] in the morning before stages 1, 3, and 6 (D1, D3, and D6). Main Outcome Measures:Reliability of Hbmass measurement was established using typical error calculated from 2 baseline measures. Individual change scores and coefficients of variation were used to assess stability during racing. Results:Typical error for Hbmass was 1.3% [95% confidence limits (CL): 0.9%, 2.5%]. Calculated 95% and 99.99% CL for percent change in Hbmass were ±3.6% and ±7.2%, respectively. Mean Hbmass remained within ±1.9% of baseline in cyclists and ±0.5% in controls. In all cases, individual change scores for both cyclists and controls fell within the 95% CL. There was a decrease in Hct (8.1% ± 2.8%) and [Hb] (9.7% ± 3.2%) throughout the tour in cyclists but not in controls. Conclusions:We demonstrate that Hbmass can be measured reliably via CO-rebreathing during a cycling tour. Unlike [Hb] and Hct, Hbmass remains stable over 6 days of racing in professional cyclists and may have potential in an antidoping context.

Lower running performance and exacerbated fatigue in soccer played at 1600 m

PURPOSE This study investigated the decrement in running performance of elite soccer players competing at low altitude and time course for abatement of these decrements. METHODS Twenty elite youth soccer players had their activity profile, in a sea-level (SL) and 2 altitude (Alt, 1600 m, d 4, and d 6) matches, measured with a global positioning system. Measures expressed in meters per minute of match time were total distance, low- and high-velocity running (LoVR, 0.01-4.16 m/s; HiVR, 4.17-10.0 m/s), and frequency of maximal accelerations (>2.78 m/s2). The peak and subsequent stanza for each measure were identified and a transient fatigue index calculated. Mean heart rate (HR) during the final minute of a submaximal running task (5 min, 11 km/h) was recorded at SL and for 10 d at Alt. Differences were determined between SL and Alt using percentage change and effect-size (ES) statistic with 90% confidence intervals. RESULTS Mean HR almost certainly increased on d 1 (5.4%, ES 1.01 ± 0.35) and remained probably elevated on both d 2 (ES 0.42 ± 0.31) and d3 (ES 0.30 ± 0.25), returning to baseline at d 5. Total distance was almost certainly lower than SL (ES -0.76 ± 0.37) at d 4 and remained probably reduced on d 6 (ES -0.42 ± 0.36). HiVR probably decreased at d 4 vs SL (-0.47 ± 0.59), with no clear effect of altitude at d 6 (-0.08 ± 0.41). Transient fatigue in matches was evident at SL and Alt, with a possibly greater decrement at Alt. CONCLUSION Despite some physiological adaptation, match running performance of youth soccer players is compromised for at least 6 d at low altitude.

Intravenous Iron Supplementation in Distance Runners with Low or Suboptimal Ferritin

PURPOSE Iron deficiency is prevalent in distance runners and may impair endurance performance. The current practice of oral supplementation is slow and often not well tolerated. The aim of this study was to assess the efficacy of intravenous (IV) iron supplementation (ferric carboxymaltose) compared with oral supplementation (ferrous sulfate) on iron status, hemoglobin mass (Hbmass), and physiological indices of running performance in distance runners. METHODS Twenty-seven highly trained distance runners with low (LOW) (ferritin <35 μg·L(-1) and transferrin saturation <20%, or ferritin <15 μg·L(-1)) or suboptimal (SUB) iron status (ferritin <65 μg·L(-1)) were supplemented with either IV iron (Ferinject®) or oral (ORAL) supplements (Ferrogradumet) for 6 wk. Iron status and Hbmass were assessed before supplementation and at 1, 2, 4, 6, and 8 wk in the four groups (IV LOW, IV SUB, ORAL LOW, and ORAL SUB). In addition, athletes completed a treadmill running test for running economy, lactate threshold, and V˙O2max before and after supplementation. RESULTS Both forms of supplementation substantially increased ferritin levels in all four groups. IV supplementation resulted in higher ferritin in both IV groups compared with both ORAL groups from week 1 onward. Hemoglobin concentration did not change substantially in any group. Hbmass increased in IV LOW (mean = +4.9%, 90% confidence interval [CI] = 1.1%-8.9%) and was accompanied by an increase in V˙O2max (mean = +3.3%, 90% CI = 0.4%-6.3%) and run time to exhaustion (mean = +9.3%, 90% CI = 0.9%-18.3%. CONCLUSIONS IV supplementation can effectively increase iron stores in iron-deficient runners within 6 wk and, if Hbmass is compromised, may enhance endurance capacity by facilitating erythropoiesis. Hbmass appears a more sensitive tool for measuring changes in whole body hemoglobin than hemoglobin concentration and may be useful in the diagnosis and follow-up for iron deficiency.

Quality control technique to reduce the variability of longitudinal measurement of hemoglobin mass

The sensitivity of the athlete blood passport to detect blood doping may be improved by the inclusion of total hemoglobin mass (Hbmass), but the comparability of Hbmass from different laboratories is unknown. To optimize detection sensitivity, the analytical variability associated with Hbmass measurement must be minimized. The aim of this study was to investigate the efficacy of using quality controls to minimize the variation in Hbmass between laboratories. Three simulated laboratories were set up in one location. Nine participants completed three carbon monoxide (CO) re‐breathing tests in each laboratory. One participant completed two CO re‐breathing tests in each laboratory. Simultaneously, quality controls containing Low (1–3%) and High (8–11%) concentrations of percent carboxyhemoglobin (%HbCO) were measured to compare hemoximeters in each laboratory. Linear mixed modeling was used to estimate the within‐subject variation in Hbmass, expressed as the coefficient of variation, and to estimate the effect of different laboratories. The analytic variation of Hbmass was 2.4% when tests were conducted in different laboratories, which reduced to 1.6% when the model accounted for between‐laboratory differences. Adjustment of Hbmass values using quality controls achieved a comparable analytic variation of 1.7%. The majority of between‐laboratory variation in Hbmass originated from the difference between hemoximeters, which could be eliminated using appropriate quality controls.

The distribution of pace adopted by cyclists during a cross-country mountain bike World Championships

Abstract The purpose of this study was to examine the distribution of pace self-selected by cyclists of varying ability, biological age and sex performing in a mountain bike World Championship event. Data were collected on cyclists performing in the Elite Male (ELITEmale; n = 75), Elite Female (ELITEfemale; n = 50), Under 23 Male (U23male; n = 62), Under 23 Female (U23female; n = 34), Junior Male (JNRmale; n = 71) and Junior Female (JNRfemale; n = 30) categories of the 2009 UCI Cross-Country Mountain Bike World Championships. Split times were recorded for the top, middle and bottom 20% of all finishers of each category. Timing splits were positioned to separate the course into technical and non-technical, uphill, downhill and rolling/flat sections. Compared with bottom performers, top performers in all male categories (ELITEmale, U23male, JNRmale) maintained a more even pace over the event as evidenced by a significantly lower standard deviation and range in average lap speed. Top performers, males, and ELITEmale athletes spent a lower percentage of overall race time on technical uphill sections of the course, compared with middle and bottom placed finishers, females, and JNRmale athletes, respectively. Better male performers adopt a more even distribution of pace throughout cross-country mountain events. Performance of lower placed finishers, females and JNRmale athletes may be improved by enhancing technical uphill cycling ability.

The effects of injury and illness on haemoglobin mass.

This study sought to quantify the effects of reduced training, surgery and changes in body mass on haemoglobin mass (Hbmass) in athletes. Hbmass of 15 athletes (6 males, 9 females) was measured 9±6 (mean±SD) times over 162±198 days, during reduced training following injury or illness. Additionally, body mass (n=15 athletes) and episodes of altitude training (n=2), iron supplementation (n=5), or surgery (n=3) were documented. Training was recorded and compared with pre-injury levels. Analysis used linear mixed models for ln(Hbmass), with Sex, Altitude, Surgery, Iron, Training and log(Body Mass) as fixed effects, and Athlete as a fixed and random effect. Reduced training and surgery led to 2.3% (p=0.02) and 2.7% (p=0.04) decreases in Hbmass, respectively. Altitude and iron increased Hbmass by 2.4% (p=0.03) and 4.2% (p=0.05), respectively. The effect of changes in body mass on Hbmass was not statistically significant (p=0.435).The estimates for the effects of surgery and altitude on Hbmass should be confirmed by future research using a larger sample of athletes. These estimates could be used to inform the judgements of experts examining athlete biological passports, improving their interpretation of Hbmass perturbations, which athletes claim are related to injury, thereby protecting innocent athletes from unfair sanctioning.

Plasma volume shifts during multiday racing.

*Corresponding author: Chris J. Gore, PhD, FACSM, Head of Physiology, Australian Institute of Sport, PO Box 176 Belconnen ACT 2616, Australia, E-mail: chris.gore@ausport.gov.au Chris J. Gore: Flinders University of South Australia, Bedford Park, Australia Jakob Morkeberg: Bispebjerg Hospital, Copenhagen, Denmark Walter Schmidt: University of Bayreuth, Bayreuth, Germany Laura Anne Garvican: Australian Institute of Sport, Canberra, Australia; and University of Canberra, Canberra, Australia Nicole Fellman: Universit é d ’ Auvergne, CHU de Clermont-Ferrand, Clermont-Ferrand, France