Blood volume and hemoglobin mass in elite athletes of different disciplines

Although it is well known that athletes have considerably larger blood volumes than untrained individuals, there is no data available describing the blood volume variability among differently trained athletes. The first aim of the study was to determine whether athletes from different disciplines are characterized by different blood volumes and secondly to what extent the blood volume can possibly limit endurance performance within a particular discipline. We investigated 94 male elite athletes subdivided into the following 6 groups: downhill skiing (DHS), swimming (S), running (R), triathlon (TA), cycling junior (CJ) and cycling professional (CP). Two groups of untrained subjects (UT) and leisure sportsmen (LS) served as controls. Total hemoglobin (tHb) and blood volume (BV) were measured by the CO-rebreathing method. In comparison to UT (mean +/- SD: tHb 11.0 +/- 1.1 g/kg, BV 78.3 +/- 7.9 ml/kg) tHb and BV were about 35 - 40 % higher in the endurance groups R, TA, CJ, and CP (e. g. in CP: tHb 15.3 +/- 1.3 g/kg, BV 107.1 +/- 7.0 ml/kg). Within the endurance groups we found no significant differences. The anaerobic discipline DHS was characterized by very low BV (87.6 +/- 3.1 ml/kg). S had an intermediate position (BV 97.4 +/- 6.1 ml/kg), probably because of the immersion effects during training in the water. VO(2)max was significantly related to tHb and BV not only in the whole group but also in all endurance disciplines. The reasons for the different BVs are an increased adaptation to training stimuli and probably also individual predisposing genetic factors.     

Blood volume and hemoglobin mass in endurance athletes from moderate altitude

PURPOSE: To determine whether total hemoglobin (tHb) mass and total blood volume (BV) are influenced by training, by chronic altitude exposure, and possibly by the combination of both conditions. METHODS: Four groups (N = 12, each) either from locations at sea level or at moderate altitude (2600 m) were investigated: 1) sea-level control group (UT-0 m), 2) altitude control group (UT-2600 m), 3) professional cyclists from sea level (C-0 m), and 4) professional cyclists from altitude (C-2600 m). All subjects from altitude were born at about 2600 m and lived all their lives (except during competitions at lower levels) at this altitude. tHb and BV were determined by the CO-rebreathing method. RESULTS: VO2max (mL x kg(-1) x min(-1)) was significantly higher in UT-0 m (45.3 +/- 3.2) than in UT-2600 m (39.6 +/- 4.0) but did not differ between C-0 m (68.2 +/- 2.7) and C-2600 m (69.9 +/- 4.4). tHb (g x kg(-1)) was affected by training (UT-0 m: 11.0 +/- 1.1, C-0 m: 15.4 +/- 1.3) and by altitude (UT-2600 m: 13.4 +/- 0.9) and showed both effects in C-2600 m (17.1 +/- 1.4). Because red cell volume showed a behavior similar to tHb and because plasma volume was not affected by altitude but by training, BV (mL x kg(-1)) was increased in C-0 m (UT-0 m: 78.3 +/- 7.9; C-0 m: 107.0 +/- 6.2) and in UT-2600 m (88.2 +/- 4.8), showing highest values in the C-2600 m group (116.5 +/- 11.4).CONCLUSION: In endurance athletes who are native to moderate altitude, tHb and BV were synergistically influenced by training and by altitude exposure, which is probably one important reason for their high performance.     

Application of altitude/hypoxic training by elite athletes

At the Olympic level, differences in performance are typically less than 0.5%. This helps explain why many contemporary elite endurance athletes in summer and winter sport incorporate some form of altitude/hypoxic training within their year-round training plan, believing that it will provide the "competitive edge" to succeed at the Olympic level. The purpose of this paper is to describe the practical application of altitude/hypoxic training as used by elite athletes. Within the general framework of the paper, both anecdotal and scientific evidence will be presented relative to the efficacy of several contemporary altitude/hypoxic training models and devices currently used by Olympic-level athletes for the purpose of legally enhancing performance. These include the three primary altitude/hypoxic training models: 1) live high+train high (LH+TH), 2) live high+train low (LH+TL), and 3) live low+train high (LL+TH). The LH+TL model will be examined in detail and will include its various modifications: natural/terrestrial altitude, simulated altitude via nitrogen dilution or oxygen filtration, and hypobaric normoxia via supplemental oxygen. A somewhat opposite approach to LH+TL is the altitude/hypoxic training strategy of LL+TH, and data regarding its efficacy will be presented. Recently, several of these altitude/hypoxic training strategies and devices underwent critical review by the World Anti-Doping Agency (WADA) for the purpose of potentially banning them as illegal performance-enhancing substances/methods. This paper will conclude with an update on the most recent statement from WADA regarding the use of simulated altitude devices.     

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

To determine the time course of hemoglobin mass (Hb_mass) to natural altitude training, Hb_mass, 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 Hb_mass, 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. Hb_mass 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. Hb_mass and [EPO] decreased on descent to sea level while ferritin increased. The mean increase in Hb_mass 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, Hb_mass increases progressively with 3 weeks of natural altitude exposure, with greater increases expected as exposure persists.     

Variability in hemoglobin mass response to altitude training camps

The present study investigated whether athletes can be classified as responders or non‐responders based on their individual change in total hemoglobin mass (tHb‐mass) following altitude training while also identifying the potential factors that may affect responsiveness to altitude exposure. Measurements were completed with 59 elite endurance athletes who participated in national team altitude training camps. Fifteen athletes participated in the altitude training camp at least twice. Total Hb‐mass using a CO rebreathing method and other blood markers were measured before and after a total of 82 altitude training camps (1350‐2500 m) in 59 athletes. In 46 (56%) altitude training camps, tHb‐mass increased. The amount of positive responses increased to 65% when only camps above 2000 m were considered. From the fifteen athletes who participated in altitude training camps at least twice, 27% always had positive tHb‐mass responses, 13% only negative responses, and 60% both positive and negative responses. Logistic regression analysis showed that altitude was the most significant factor explaining positive tHb‐mass response. Furthermore, male athletes had greater tHb‐mass response than female athletes. In endurance athletes, tHb‐mass is likely to increase after altitude training given that hypoxic stimulus is appropriate. However, great inter‐ and intra‐individual variability in tHb‐mass response does not support classification of an athlete permanently as a responder or non‐responder. This variability warrants efforts to control numerous factors affecting an athlete's response to each altitude training camp.     

Antioxidant‐rich foods and response to altitude training: A randomized controlled trial in elite endurance athletes

High doses of isolated antioxidant supplements such as vitamin C and E have demonstrated the potential to blunt cellular adaptations to training. It is, however, unknown whether intake of high doses of antioxidants from foods has similar effects. Hence, the aim of the study was to investigate whether intake of antioxidant‐rich foods affects adaptations to altitude training in elite athletes. In a randomized controlled trial, 31 national team endurance athletes (23 ± 5 years) ingested antioxidant‐rich foods (n = 16) or eucaloric control foods (n = 15) daily during a 3‐week altitude training camp (2320 m). Changes from baseline to post‐altitude in hemoglobin mass (Hb_mass; optimized CO rebreathing), maximal oxygen uptake (VO _2max; n = 16) or 100 m swimming performance (n = 10), and blood parameters were compared between the groups. The antioxidant group significantly increased total intake of antioxidant‐rich foods (~118%) compared to the control group during the intervention. The total study population improved VO _2max by 2.5% (1.7 mL/kg/min, P  = .006) and Hb_mass by 4.7% (48 g, P  < .001), but not 100 m swimming performance. No difference was found between the groups regarding changes in Hb_mass, VO _2max or swimming performance. However, hemoglobin concentration increased more in the antioxidant group (effect size = 0.7; P  = .045) with a concomitantly larger decrease in plasma and blood volumes compared to control group. Changes in ferritin and erythropoietin from pre‐ to post‐altitude did not differ between the groups. Doubling the intake of antioxidant‐rich foods was well tolerated and did not negatively influence the adaptive response to altitude training in elite endurance athletes.     

Differential reflex adaptations following sensorimotor and strength training in young elite athletes

In young elite athletes the influence of a sensorimotor training (SMT = balance training) on strength, jump height and spinal reflex excitability was compared with adaptations induced by strength training (ST). Seventeen athletes were randomly assigned to either a SMT or a ST group. Before and after 6 weeks of training, maximal isometric strength (MVC) and rate of force development (RFD (max)) were determined. Changes in jump height and EMG activity were assessed during squat- (SJ), countermovement- (CMJ) and drop-jump (DJ). To evaluate neural adaptations, H-reflex recruitment was recorded at rest and during dynamic activation of the plantarflexors following stance perturbation. MVC was enhanced after ST but not influenced by SMT. RFD (max) was not affected by any training. Both SMT and ST significantly improved jump performance in SJ, CMJ, and DJ. Maximum H-reflex to maximum M-wave ratios (H (max)/M (max)-ratios) at rest remained unchanged. During stance perturbation, H (max)/M (max)-ratios were significantly reduced following SMT whereas ST augmented H (max)/M (max)-ratios (p < 0.05). In contrast to other studies, no changes in RFD were found. This may be explained by methodological and/or training specific differences. However, both SMT and ST improved jump performance in well trained young athletes but induced opposing adaptations of the H (max)/M (max)-ratio when measured during dynamic contractions. These adaptations were task-specific as indicated by the unchanged reflexes at rest. Decreased spinal excitability following SMT was interpreted as the attempt to improve movement control, whereas augmented excitability following ST accounts for the effort to enhance motoneuron output. Functionally, our results emphasise that SMT is not only beneficial for prevention and rehabilitation but also improves athletic performance.     

Mental fatigue increases across a 16-week pre-season in elite female athletes

ObjectivesTo examine potential changes in mental and physical fatigue across an elite netball pre-season training phase and relationships between mental fatigue, physical fatigue, salivary cortisol (sCort) and alpha-amylase (sAA).DesignObservational with repeated measures.MethodsAcross a 16-week pre-season, 10 elite female netballers (25.3 ± 3.7y) rated their physical fatigue, mental fatigue and readiness to perform on 100-mm visual analogue scales, and provided salivary samples for sCort and sAA analyses.ResultsLinear mixed model analyses revealed elevated (p < 0.05) ratings of mental fatigue for weeks 12, 14 and 15 v 1; 12, 14 and 15 v 4 and 14 v 7. Higher (p < 0.05) ratings of physical fatigue were reported on weeks 6, 10, 11 and 12–16 compared to week 4; and 10 and 13 compared to week 7. Moderate and large ES differences were found between multiple weeks. Mental and physical fatigue demonstrated a shared variance of 14.3% (r = 0.38, p < 0.001) and an inverse relationship was observed between mental fatigue and readiness to perform (r = ?0.50; p < 0.001). Changes in sCort nor sAA were not related to changes in mental or physical fatigue.ConclusionsMental fatigue fluctuated across the 16-week pre-season phase with elevated ratings observed in the later weeks. Whilst value remains in identifying subjective tools to assess mental fatigue; salivary biomarkers do not appear to be a suitable objective indicator of mental fatigue in the applied sporting environment. Practitioners should work to identify and manage mental fatigue with the same level of importance given to the periodisation of physical fatigue.     

Modelling the relationships between training, anxiety, and fatigue in elite athletes

This study investigated the effects of 40-week training on anxiety and perceived fatigue in four elite triathletes. Anxiety and perceived fatigue were self-reported by the subjects twice a week by the way of a specific questionnaire and were linked by a mathematical model to the training loads calculated from the exercise heart rate. A significant relationship (r=0.32; p<0.001) between the training loads and anxiety was identified using a two-component model: a first, negative (i.e., anxiety decreased) short-term (tau (1)=23 days) function and a second, positive long-term (tau (2)=59 days) function. The relationship between the training loads and perceived fatigue was significant (r=0.30; p<0.001), with one negative function (tau (1)=4 days). This mathematical model can potentially describe the relationships between training loads and anxiety or perceived fatigue and may improve both the adjustment of the duration of tapering and the early detection of staleness.     

Sickle cell trait in French West Indian elite sprint athletes

The aim of this study was to establish the percentage of sickle cell trait (SCT) carriers among French West Indian sprinters selected for the French National Team in 2000. The investigation determined the number of SCT carriers and the number of national records they had established. Sixteen athletes were indexed (6 males and 10 females). The athletes were within the ranges of 20-33 years, 161-186 cm and 60-80 kg. The results showed the presence of SCT carriers in this population among whom three were SCT carriers (2 males and 1 female) (18.75%). Moreover, there is a significantly higher percentage of titles and records held by the SCT carriers (38.6% and 50%, respectively). In conclusion, this study shows that sickle cell trait carriers are able to perform sprint exercises at the highest levels, and it further indicates that brief and explosive exercise involving mainly the alactic anaerobic metabolism may be enhanced by HbS.     

Individual variation in the erythropoietic response to altitude training in elite junior swimmers

Objectives: Inter-individual variations in sea level performance after altitude training have been attributed, at least in part, to an inter-individual variability in hypoxia induced erythropoiesis. The aim of the present study was to examine whether the variability in the increase in total haemoglobin mass after training at moderate altitude could be predicted by the erythropoietin response after 4 h exposure to normobaric hypoxia at an ambient Po₂ corresponding to the training altitude.

Methods: Erythropoietin levels were measured in 16 elite junior swimmers before and after 4 h exposure to normobaric hypoxia (Fio₂ 0.15, ~2500 m) as well as repeatedly during 3 week altitude training (2100–2300 m). Before and after the altitude training, total haemoglobin mass (CO rebreathing) and performance in a stepwise increasing swimming test were determined.

Results: The erythropoietin increase (10–185%) after 4 h exposure to normobaric hypoxia showed considerable inter-individual variation and was significantly (p<0.001) correlated with the acute erythropoietin increase during altitude training but not with the change in total haemoglobin mass (significant increase of ~6% on average). The change in sea level performance after altitude training was not related to the change in total haemoglobin mass.

Conclusions: The results of the present prospective study confirmed the wide inter-individual variability in erythropoietic response to altitude training in elite athletes. However, their erythropoietin response to acute altitude exposure might not identify those athletes who respond to altitude training with an increase in total haemoglobin mass.

     

Left ventricular mass, geometry and filling in elite female and male endurance athletes

We compared echocardiographic findings in female (n=30) and male (n=30) endurance athletes to age-matched female (n=15) and male (n=15) sedentary controls. The differences between athletes and controls were similar in both sexes; only left ventricular (LV) mass and septum thickness differed slightly more in men than in women (67% vs 55%, P=0.004, and 36% vs 30%, P=0.03, respectively). LV wall thicknesses were in the normal range in all women, while four (13%) male athletes exceeded 13 mm. In conclusion, the effects of endurance training on echocardiographic findings appear to be quite similar in women and men. However, in female athletes with an abnormally thick left ventricular wall a thorough cardiac evaluation is indicated. This contrasts with male athletes, in whom LV wall thicknesses of over 13 mm are a not uncommon finding.