Cycling Stage Race Research Articles

Dynamics of Gut Microbiota and Short-Chain Fatty Acids during a Cycling Grand Tour Are Related to Exercise Performance and Modulated by Dietary Intake.

Regular exercise has been described to modify both the diversity and the relative abundance of certain bacterial taxa. To our knowledge, the effect of a cycling stage race, which entails extreme physiological and metabolic demands, on the gut microbiota composition and its metabolic activity has not been analysed. The aim of this cohort study was to analyse the dynamics of faecal microbiota composition and short-chain fatty acids (SCFAs) content of professional cyclists over a Grand Tour and their relationship with performance and dietary intake. 16 professional cyclists competing in La Vuelta 2019 were recruited. Faecal samples were collected at four time points: the day before the first stage (A); after 9 stages (B); after 15 stages (C); and on the last stage (D). Faecal microbiota populations and SCFA content were analysed using 16S rRNA sequencing and gas chromatography, respectively. A principal component analysis (PCA) followed by Generalised Estimating Equation (GEE) models were carried out to explore the dynamics of microbiota and SCFAs and their relationship with performance. Bifidobacteriaceae, Coriobacteriaceae, Erysipelotrichaceae, and Sutterellaceae dynamics showed a strong final performance predictive value (r = 0.83, ranking, and r = 0.81, accumulated time). Positive correlations were observed between Coriobacteriaceae with acetate (r = 0.530) and isovalerate (r = 0.664) and between Bifidobacteriaceae with isobutyrate (r = 0.682). No relationship was observed between SCFAs and performance. The abundance of Erysipelotrichaceae at the beginning of La Vuelta was directly related to the previous intake of complex-carbohydrate-rich foods (r = 0.956), while during the competition, the abundance of Bifidobacteriaceae was negatively affected by the intake of simple carbohydrates from supplements (r = -0.650). An ecological perspective represents more realistically the relationship between gut microbiota composition and performance compared to single-taxon approaches. The composition and periodisation of diet and supplementation during a Grand Tour, particularly carbohydrates, could be designed to modulate gut microbiota composition to allow better performance.

A multi-parametric approach to remove the influence of plasma volume on the athlete biological passport during a Union Cycliste Internationale cycling stage race.

Fluctuations in plasma volume (PV) present potential confounders within the concentration-based markers of the haematological athlete biological passport (ABP). Here, a multi-parametric approach involving a simple blood test is applied to the current ABP adaptive model in an attempt to remove the influence of PV expansion, induced by a cycling stage race. Blood samples were obtained from 29 professional cyclists (14 male, 15 female) before, during and after 4-5 consecutive days of racing. Whole blood was analysed in accordance with the World Anti-Doping Agency ABP guidelines for haemoglobin ([Hb]) concentration and platelets. Serum and plasma were analysed for transferrin, albumin, calcium, creatinine, total protein and low-density lipoprotein. PV variation (Z-scores) was estimated using a multi-parametric model (consisting of the biomarkers mentioned earlier) and compared against calculated variations in PV (measured via CO-rebreathing). Significant reductions in [Hb] and the OFF-score were observed in female cyclists after 3 and 4 days of racing, with accompanying increases in PV, which returned to baseline values 4 days post competition. Similarly, a significant increase in PV was observed in male cyclists after 3 and 5 days of racing. When individual estimations of PV variance were applied to the adaptive model, the upper and lower reference predictions for [Hb] and the OFF-score were refined such that all outliers consistent with racing-induced PV changes were removed. The PV model appears capable of reducing the influence of PV on concentration-dependent markers during competition. This is an important step towards the inclusion of the PV correction in the ABP haematological module.

Plasma oxidative stress (hydrogen peroxide/trolox) responses during a 7-day road cycling stage race and a competitive football match in top-level athletes

The aim of this study was to compare the response induced by regular competition on free oxygen radicals (hydrogen peroxide), free oxygen radical defence (Trolox) and hydrogen peroxide/Trolox balance in plasma, between top-level male road cyclists and top-level male football players. 9 male top-level road cyclists (age 27.2 ± 3.5 years) and 10 male top-level football players (age 27.3 ± 4.3 years) completed a 7-day road cycling stage race and a football match, respectively. Free oxygen radicals (hydrogen peroxide) and free oxygen radical defence (Trolox) were measured 2 h before and 1 h after the corresponding competition. Body composition was determined previously by means of dual-energy X-ray absorptiometry. Both competitions induced a significant increase in hydrogen peroxide for each group. Trolox decreased and hydrogen peroxide/Trolox balance increased, significantly, for road cyclists. For football players, Trolox increased and hydrogen peroxide/Trolox balance decreased, significantly. Hydrogen peroxide/Trolox balance differences had a significant positive correlation against respective competitive loads for both groups. Hydrogen peroxide differences showed a significant negative correlation and Trolox differences indicated a significant positive correlation with body mass index, body fat, and lean body mass. This study suggests that football players may be able to maintain oxidative stress balance in plasma after a football match whilst road cyclists may experience a hyper-oxidative stress state in plasma after a 7-day road cycling stage race. In addition, both, competitive load and body mass are related to the oxidative stress balance in plasma in these two groups of top-level athletes.

Impact of Magnesium Supplementation in Muscle Damage of Professional Cyclists Competing in a Stage Race.

Magnesium is a cofactor of different enzymatic reactions involved in anabolic and catabolic processes that affect muscular performance during exercise. In addition, it has been suggested that magnesium could participate in maintaining muscle integrity during demanding effort. The main purpose of this study was to analyze the effects of magnesium supplementation in preventing muscle damage in professional cyclists taking part in a 21-day cycling stage race. Eighteen male professional cyclists (n = 18) from two teams were recruited to participate in the research. They were divided into 2 groups: the control group (n = 9) and the magnesium-supplemented group (n = 9). The supplementation consisted of an intake of 400 mg/day of magnesium during the 3 weeks of competition. Blood samples were collected according to World Anti-Doping Agency rules at three specific moments during competition: immediately before the race; mid competition; and before the last stage. Levels of serum and erythrocyte magnesium, lactate dehydrogenase, creatinine kinase, aspartate transaminase, alanine transaminase, myoglobin, aldolase, total proteins, cortisol and creatinine were determined. Serum and erythrocyte magnesium levels decreased during the race. Circulating tissue markers increased at the end of the race in both groups. However, myoglobin increase was mitigated in the supplemented group compared with the controls. We conclude that magnesium supplementation seems to exert a protective effect on muscle damage.

Body fluid status, plasma volume change and its relationship to physical effort during a multistage professional road cycling race

ABSTRACTMultistage cycling races are very demanding and may profoundly affect the body’s fluid homeostasis. This study aimed at monitoring body fluid volume and plasma volume (PV) changes during multi-stage cycling and to investigate whether changes are associated to work output and perceived exertion during the competition. During the Tour of the Alps cycling stage race 2017 daily hematocrit and hemoglobin evaluations, body weight, bioimpedance, RPE and power output measurements were performed on eight professional road cyclists. Results show modest to large changes in bioimpedance and blood hematocrit values during the race. Work accomplished during stage one was related to changes in vector length and body weight (n = 6, r = 0.821, p = 0.045 and r = ‒0.852, p = 0.031, respectively). Additionally, PV changes were associated with vector length changes (r = ‒0.759, p = 0.029). During the last stage, PV changes were related to reactance (Xc/H) changes (r = ‒0.716, p = 0.046). The physical work performed during the first stage seems to strongly influence fluid volumes, which on the other hand showed some associations to PV changes. These associations were not evident during the following stages but instead a relationship between Xc/h and PV changes occurred, possible indicating fluid shifts. Bioimpedance thus could be a useful tool to identify fluids shift during such competitions.

Testosterone and cortisol in 93 elite road cyclists during a 10-day stage race: relationship with final ranking

Cycling stage racing is a heavy and strenuous endurance event and it has been recognized that such exercise can affect the hormonal asset of hypothalamic–pituitary–adrenal (HPA) and hypothalamic–pituitary–testicular (HPT) axis. However, in cycling, literature on such changes is scarce and published data have been derived from small samples of athletes. The aims of study were to provide normative values for serum hormonal steroid values, changes in serum hormonal steroids and assess any relationships between a riders’ performance and their hormonal profile before and after the stage race. Male elite professional cyclists (n = 93) competing in the 2010 GiroBio 10-day stage race participated in this study. Blood chemistry measurements included cortisol (C), testosterone (T), free testosterone (fT) and sex hormone binding globulin (SHBG). Data are expressed as mean ± SD. Serum concentration of C and fT were lower at the end of GiroBio [C (nmol L−1): 559.34 ± 95.71 vs 469.59 ± 51.12; fT (pmol ml−1): 63.91 ± 27.85 vs 37.51 ± 17.86]. These serum hormonal (mean values ± 2SD) values may be near the physiological ceiling for elite cyclists. There was inverse correlation among average final speed and pre-competition serum concentration of T (r = −0.265, p = 0.01); average final speed was negatively correlated with riders body mass pre and post the 10-day stage event. In conclusion, pre-GiroBio serum C levels could be a useful benchmark to preserve riders’ health and, moreover, our data confirm that the strenuous effort sustained by riders during a stage race induces appreciable changes in the hormonal profile. In addition, our data suggest that lower levels of T could represent favourable prerequisite to cope better in a cycling stage race.

The effect of cumulative endurance exercise on leptin and adiponectin and their role as markers to monitor training load.

Leptin and adiponectin play an essential role in energy metabolism. Leptin has also been proposed as a marker for monitoring training load. So far, no studies have investigated the variability of these hormones in athletes and how they are regulated during cumulative exercise. This study monitored leptin and adiponectin in 15 endurance athletes twice daily in the days before, during and after a 9-day simulated cycling stage race. Adiponectin significantly increased during the race (p = 0.001) and recovery periods (p = 0.002) when compared to the baseline, while leptin decreased significantly during the race (p < 0.0001) and returned to baseline levels during the recovery period. Intra-individual variability was substantially lower than inter-individual variability for both hormones (leptin 34.1 vs. 53.5%, adiponectin 19% vs. 37.2%). With regards to exercise, this study demonstrated that with sufficient, sustained energy expenditure, leptin concentrations can decrease within the first 24 hours. Under the investigated conditions there also appears to be an optimal leptin concentration which ensures stable energy homeostasis, as there was no significant decrease over the subsequent race days. In healthy endurance athletes the recovery of leptin takes 48-72 hours and may even show a supercompensation-like effect. For adiponectin, significant increases were observed within 5 days of commencing racing, with these elevated values failing to return to baseline levels after 3 days of recovery. Additionally, when using leptin and adiponectin to monitor training loads, establishing individual threshold values improves their sensitivity.

Changes in urinary amino acids excretion in relationship with muscle activity markers over a professional cycling stage race: in search of fatigue markers

The aim of this study was to identify the relationship between metabolic effort, muscular damage/activity indices, and urinary amino acids profile over the course of a strenuous prolonged endurance activity, as a cycling stage race is, in order to identify possible fatigue markers. Nine professional cyclists belonging to a single team, competing in the Giro d'Italia cycling stage race, were anthropometrically characterized and sampled for blood and urine the day before the race started, and on days 12 and 23 of the race. Diet was kept the same over the race, and power output and energy expenditure were recorded. Sera were assayed for muscle markers (lactate dehydrogenase, aspartate aminotransferase, and creatine kinase activities, and blood urea nitrogen), and creatinine, all corrected for plasma volume changes. Urines were profiled for amino acid concentrations, normalized on creatinine excretion. Renal function, in terms of glomerular filtration rate, was monitored by MDRD equation corrected on body surface area. Creatine kinase activity and blood urea were increased during the race as did serum creatinine while kidney function remained stable. Among the amino acids, taurine, glycine, cysteine, leucine, carnosine, 1-methyl histidine, and 3-methyl histidine showed a net decreased, while homocysteine was increased. Taurine and the dipeptide carnosine (β-alanyl-L-histidine) were significantly correlated with the muscle activity markers and the indices of effort. In conclusion, the metabolic profile is modified strikingly due to the effort. Urinary taurine and carnosine seem useful tools to evaluate the muscle damage and possibly the fatigue status on a long-term basis.

High altitude, prolonged exercise, and the athlete biological passport.

The Athlete Biological Passport (ABP) detects blood doping in athletes through longitudinal monitoring of erythropoietic markers. Mathematical algorithms are used to define individual reference ranges for these markers for each athlete. It is unclear if altitude and exercise can affect the variables included in these calculations in a way that the changes might be mistaken for blood manipulation. The aim of this study was to investigate the influence of the simultaneous strenuous exercise and low to high altitude exposure on the calculation algorithms of the ABP. 14 sea level (SL) and 11 altitude native (ALT) highly trained athletes participated in a 14-day cycling stage race taking place at an average altitude of 2496 m above sea level (min. 1014 m, max. 4120 m), race distances ranged between 96 and 227 km per day. ABP blood measures were taken on days -1,3,6,10,14 (SL) and -1,9,15 (ALT) of the race. Four results from three samples of two different SL athletes exceeded the individual limits at the 99% specificity threshold and one value at 99.9%. In ALT, three results from three samples of three different athletes were beyond the individual limits at 99%, one at 99.9%. The variations could be explained by the expected physiological reaction to exercise and altitude. In summary, the abnormalities observed in the haematological ABP´s of well-trained athletes during extensive exercise at altitude are limited and in line with expected physiological changes.

HGH isoform differential immunoassays applied to blood samples from athletes: Decision limits for anti-doping testing

ObjectiveTo detect hGH doping in sport, the World Anti-Doping Agency (WADA)-accredited laboratories use the ratio of the concentrations of recombinant hGH (‘rec’) versus other ‘natural’ pituitary-derived isoforms of hGH (‘pit’), measured with two different kits developed specifically to detect the administration of exogenous hGH. The current joint compliance decision limits (DLs) for ratios derived from these kits, designed so that they would both be exceeded in fewer than 1 in 10,000 samples from non-doping athletes, are based on data accrued in anti-doping labs up to March 2010, and later confirmed with data up to February–March 2011. In April 2013, WADA asked the authors to analyze the now much larger set of ratios collected in routine hGH testing of athletes, and to document in the peer-reviewed literature a statistical procedure for establishing DLs, so that it be re-applied as more data become available. DesignWe examined the variation in the rec/pit ratios obtained for 21,943 screened blood (serum) samples submitted to the WADA accredited laboratories over the period 2009–2013. To fit the relevant sex- and kit-specific centiles of the logs of the ratios, we classified ‘rec/pit’ ratios based on low ‘rec’ and ‘pit’ values as ‘negative’ and fitted statistical distributions to the remaining log-ratios. The flexible data-driven quantile regression approach allowed us to deal with the fact that the location, scale and shape of the distribution of the modeled ‘rec/pit’ ratios varied with the concentrations of the ‘rec’ and ‘pit’ values. The between-kit correlation of the ratios was included in the fitting of the DLs, and bootstrap samples were used to quantify the estimation error in these limits. We examined the performance of these limits by applying them to the data obtained from investigator-initiated hGH administration studies, and in athletes in a simulated cycling stage race. ResultsThe mean and spread of the distribution of the modeled log-ratios depended in different ways on the magnitude of the rec and pit concentrations. Ultimately, however, the estimated limits were almost invariant to the concentrations, and similar to those obtained by fitting simpler (marginal) log-normal and Box–Cox transformed distributions. The estimated limits were similar to the (currently-used) limits fitted to the smaller datasets analyzed previously. In investigator-initiated instances, the limits distinguished recent use of rec-hGH from non-use. ConclusionsThe distributions of the rec/pit ratios varied as a function of the rec and pit concentrations, but the patterns in their medians and spreads largely canceled each other. Thus, ultimately, the kit- and sex-specific ratio DL obtained from the simpler model was very close to the ‘curve of DLs’ obtained from the more complex one. Both were close to previously established limits.

The effect of a period of intense exercise on the marker approach to detect growth hormone doping in sports.

The major objective of this study was to investigate the effects of several days of intense exercise on the growth hormone marker approach to detect doping with human growth hormone (hGH). In addition we investigated the effect of changes in plasma volume on the test. Fifteen male athletes performed a simulated nine-day cycling stage race. Blood samples were collected twice daily over a period of 15 days (stage race + three days before and after). Plasma volumes were estimated by the optimized CO Rebreathing method. IGF-1 and P-III-NP were analyzed by Siemens Immulite and Cisbio Assays, respectively. All measured GH 2000 scores were far below the published decision limits for an adverse analytical finding. The period of exercise did not increase the GH-scores; however the accompanying effect of the increase in Plasma Volume yielded in essentially lower GH-scores. We could demonstrate that a period of heavy, long-term exercise with changes in plasma volume does not interfere with the decision limits for an adverse analytical finding.

Mean speed in professional cycling: No evidence of decline

The aim of this article was to evaluate the mean speed progression of the three major cycling stage races in order to empirically establish whether excellent in performance in professional cycling is to some extent correlated with the trend of blood doping and anti-doping throughout more than a century of official cycling competitions. We retrieved data about the mean speed of the winners of the Tour de France, Giro d’Italia and Vuelta a Espana, since their beginning. A linear correlation has then been calculated between the years and the mean speed in km/h for each single major cycling stage race, as well as for the mean speed of the winners of the three major cycling stage races in the same year. Although a highly significant correlation was found between years and mean speed of the winners of each single major cycling stage race during the same year (r=0.941; p<0.001), a number of differential trends were observed. More specifically, from 1903 to 1925 the association was inverse, between 1926 and 2000 the relationship was positive, whereas in the period 2001–2013 the relationship became virtually flat. This data suggests that a strengthened policy of anti-doping testing may have been effective in the past 15 years for curbing the use of performance-enhancing substances.

Variability of serum markers of erythropoiesis during a cycling stage race

Introduction: The Athlete Biological Passport for the fight against doping is currently based on longitudinal monitoring for abnormal changes in cellular blood parameters. Serum parameters related to altered erythropoiesis could be considered for inclusion in the passport. The aim of this study was to quantify the changes in such parameters in athletes during a period of intense exercise.

Bone‐muscle unit activity, salivary steroid hormones profile, and physical effort over a 3‐week stage race

Muscle traction and bone metabolism are functionally linked and co-regulated by a series of factors. Although a role for steroid hormones was hypothesized, a clear definition of the bone-muscle interconnection still lacks. To investigate this relationship, we studied bone metabolism, muscle activity, and salivary steroid hormones profile in relation with the physical effort across a cycling stage race, a model of effort in absence of load. Nine pro-cyclists were recruited; body weight and power output/energy expenditure were recorded. Diet was kept constant. Saliva was collected at days -1, 4, 8, 12, 14, 19, and 23; blood and urine were collected at days -1, 12, and 23. Salivary steroid hormones [cortisol, dehydroepiandrosterone (DHEA), testosterone, and estradiol], serum lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and creatine kinase (CK) activities, plasma sclerostin, and urinary calcium and phosphorous were measured. Cortisol remained constant, testosterone decreased at day 4, and estradiol and DHEA firstly increased and then returned to basal levels. Hormone concentrations were not correlated with plasma volume shifts. LDH, CK, AST, sclerostin, and urinary calcium and phosphorous increased. DHEA and estradiol correlated with the physical effort and the bone-muscular markers. A relationship between muscle activity, in absence of load, and bone resorption emerged under a putative regulation by DHEA and estradiol.

Comparison of the Hematological Profile of Elite Road Cyclists during the 2010 and 2012 GiroBio Ten-Day Stage Races and Relationships with Final Ranking

Cycling stage races are strenuous endurance events during which exercise-induced variations in hematological parameters are consistently observed. However, specific literature on such changes is scarce and published data have been derived from small samples of athletes. The aims of this study were: (1) to determine the hematological response to middle-term strenuous endurance; and (2) to determine whether a relationship exists between the athlete-specific hematological profile and final placement in a cycling stage race. The study population was male professional cyclists (n = 253) competing in the 2010 (n = 144) and 2012 (n = 109) GiroBio 10-day stage races. Blood draws taken before the start of the race, at mid-race, and at end-race were performed in strict compliance with academic and anti-doping pre-analytical warnings. Blood chemistry included white blood cell, red blood cell, hemoglobin concentration, hematocrit, mean corpuscular volume (MCV), mean hemoglobin content (MCH), mean corpuscular hemoglobin content (MCHC), platelets, and reticulocyte relative and absolute counts. Compared to baseline values, erythrocyte, hemoglobin, hematocrit, MCHC, platelet and reticulocyte counts were all consistently lower at mid-race, but returned to normal by race-end, while leukocytes were increased in the final phase. MCV increased during both events. MCH increased in the first part to then return to baseline in the 2012 race. The calculated OFF-score consistently decreased in the first half of the race before increasing, but remained lower than the baseline value. The trends of variation in hematological parameters were substantially similar in both events. There was an inverse, albeit weak, relationship between placement and erythrocyte, platelet, hemoglobin, hematocrit and OFF-score values in the 2010, but not in the 2012 race. In conclusion, the data confirm that, in this large series of elite road cyclists, the strenuous effort a rider sustains during a stage race induces appreciable changes in the hematological profile.

The effect of a period of intensive exercise on the isoform test to detect growth hormone doping in sports

ObjectiveThe major objective of this study was to investigate the effects of several days of intense exercise on growth hormone (hGH) testing using the World Anti-Doping Agencies hGH isoform differential immunoassays. Additionally the effects of circadian variation and exercise type on the isoform ratios were also investigated. Study design15 male athletes performed a simulated nine day cycling stage race. Blood samples were collected twice daily over a period of 15days (stage race+three days before and after). hGH isoforms were analysed by the official WADA immunoassays (CMZ Assay GmbH). ResultsAll measured isoform ratios were far below the WADA decision limits for an adverse analytical finding. Changes in the isoform ratios could not be clearly connected to circadian variation, exercise duration or intensity. ConclusionsThe present study demonstrates that the hGH isoform ratios are not significantly affected by exercise or circadian variation. We demonstrated that heavy, long term exercise does not interfere with the decision limits for an adverse analytical finding.

Bone and energy metabolism parameters in professional cyclists during the Giro d'Italia 3-weeks stage race.

Cycling is a not weight-bearing activity and is known to induce bone resorption. Stage races are really strenuous endurance performances affecting the energy homeostasis. The recently highlighted link, in the co-regulation of bone and energy metabolism, demonstrates a central role for the equilibrium between carboxylated and undercarboxylated forms of osteocalcin. Aim of this study was to understand the acute physiological responses to a cycling stage race in terms of bone turnover and energy metabolism and the possible co-regulative mechanisms underlying their relationship. We studied nine professional cyclists engaged in 2011 Giro d’Italia stage race. Pre-analytical and analytical phases tightly followed academic and anti-doping authority’s recommendations. Bone and energy metabolism markers (bone alkaline phosphatase, tartrate-resistant acid phosphatase 5b, total and undercarboxylated osteocalcin, leptin and adiponectin) and related hormones (cortisol and testosterone) were measured, by Sandwich Enzyme Immunoassays, at days -1 (pre-race), 12 and 22 during the race. The power output and the energy expenditure (mean and accumulated) were derived and correlated with the biochemical indexes. During the race, bone metabolism showed that an unbalance in behalf of resorption, which is enhanced, occurred along with a relative increase in the concentration of the undercarboxylated form of osteocalcin that was indirectly related to the enhanced energy expenditure, through adipokines modifications, with leptin decrease (high energy consumption) and adiponectin increase (optimization of energy expenditure). The exertion due to heavy effort induced a decrease of cortisol, while testosterone levels resulted unchanged. In conclusion, during a 3-weeks stage race, bone metabolism is pushed towards resorption. A possible relationship between the bone and the energy metabolisms is suggested by the relative correlations among absolute and relative concentrations trends of undercarboxylated OC, adipokines concentrations, BMI, fat mass (%), power output and the derived energy expenditure.

Haematological and iron metabolism parameters in professional cyclists during the Giro d’Italia 3-weeks stage race

Haematological assessment is crucial for evaluating athletes healthy status. Professional athletes experience physiological modifications during competitions and over a season: the risk of sports anaemia is high. Few descriptions of haematological parameters behaviour during a 3-weeks cycling stage race have been published. We studied nine professional cyclists engaged in the 2011 Giro d'Italia stage race. Pre-analytical and analytical phases tightly followed academic and anti-doping authorities' recommendations. Haematological and iron metabolism parameters were measured days -1 (pre-race), 12 and 22 during the race. Haemoglobin, red blood cells and haematocrit decreased during the race with a stabilisation in the second half, but final values were lower than baseline. Reticulocytes did not modify, whilst the immature reticulocyte fraction increased. No differences were found in red blood cells volume and corpuscular haemoglobin content, neither in iron metabolism markers. The acute phase proteins, haptoglobin and C-reactive protein, both increased over the race, while haemoglobin and haptoglobin were inversely related. These data are important for improving the knowledge of physiological modifications in haematological and iron metabolism parameters of professional athletes during highly demanding competitions. This is the first report, in the ambit of a stage race, in which the pre-analytical phase standardisation has been applied.

Cardiac indexes, cardiac damage biomarkers and energy expenditure in professional cyclists during the Giro d’Italia 3-weeks stage race

The study of cardiac response to strenuous and continuous exercise is crucial to understanding the physiology of endurance. N-terminal proB-type natriuretic peptide (NT-proBNP) is a potential marker for monitoring myocardial wall stress, and troponins (TnT and TnI) are widely used in the diagnosis of cardiac ischemia and infarction. Strenuous exercise may generate transitory ischemia, myocardial stress, and diastolic left ventricular dysfunction, inducing the increased production of both these biomarkers. We measured changes in NT-proBNP and TnT in elite cyclists during a 3-week stage race, a model of strenuous exercise. The study population was 9 professional cyclists participating in the 2011 Giro d'Italia. Pre-analytical and analytical phases scrupulously followed official recommendations. Anthropometric data, net energy expenditure and cardiac indexes (rate, diastolic and systolic blood pressure) were recorded. Blood samples were drawn pre-race (day - 1) and at days 12 and 22; NT-proBNP and highly sensitive-troponin (Hs-TnT) concentrations were assayed and corrected for plasma volume changes. Body-mass index decreased and energy expenditure increased by 52% during the race. NT-proBNP concentrations increased [day -1:23.52 ng/L (9.67-34.33); day 12:63.46 ng/L (22.15-93.31); P = 0.039; day 22:89.26 ng/L (34.66-129.78) vs.day -1; P < 0.001] and correlated with heart rate (r = -0.51; P = 0.006), systolic pressure (r = 0.39; P = 0.046) and energy expenditure (r = 0.70; P < 0.001). TnT concentrations did not vary, but a widened TnT amplitude distribution was observed. Increases in NT-proBNP correlated with higher energy expenditure over a 3-week cycling stage race, possibly indicating myocardial stress.

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

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...