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... After a 15 min warm-up, participants started leg cycling at a low intensity of 2.0 W kg −1 of body weight. Exercise intensity was increased 0.5 W kg −1 every 10 min as previously described (San-Millán et al., 2009). Power output, heart rate and lactate were measured throughout the entire test and recorded every 10 min including at the end of the test. ...
... However, it is interesting to appreciate that this classification also revealed significant differences at baseline, even prior to the graded exercise test. As the measurements of blood lactate accumulation during a short, graded exercise test can discriminate performance in different groups of cyclists (San-Millán et al., 2009) these results indicate that metabolomic measurements at baseline and during graded exercise testing may serve to expand the predictive qualities of lactate measurement alone. In support, it is noteworthy that the World-Tour cycling season started two weeks after our testing was performed. ...
... Increased glycolytic markers have also been identified in plasma during exercise (Jacobs et al., 2014). While lactate production as a function of output has been shown to discriminate cyclists of differing training status (San-Millán et al., 2009) all cyclists reached a point of exhaustion just prior to whole blood sampling for metabolomics. As such, only a few glycolytic intermediates trended with rates of lactate accumulation, but none significantly differed between the two groups. ...
The study of elite athletes provides a unique opportunity to define the upper limits of human physiology and performance. Across a variety of sports, these individuals have trained to optimize the physiological parameters of their bodies in order to compete on the world stage. To characterize endurance capacity, techniques such as heart rate monitoring, indirect calorimetry, and whole blood lactate measurement have provided insight into oxygen utilization, and substrate utilization and preference, as well as total metabolic capacity. However, while these techniques enable the measurement of individual, representative variables critical for sports performance, they lack the molecular resolution that is needed to understand which metabolic adaptations are necessary to influence these metrics. Recent advancements in mass spectrometry-based analytical approaches have enabled the measurement of hundreds to thousands of metabolites in a single analysis. Here we employed targeted and untargeted metabolomics approaches to investigate whole blood responses to exercise in elite World Tour (including Tour de France) professional cyclists before and after a graded maximal physiological test. As cyclists within this group demonstrated varying blood lactate accumulation as a function of power output, which is an indicator of performance, we compared metabolic profiles with respect to lactate production to identify adaptations associated with physiological performance. We report that numerous metabolic adaptations occur within this physically elite population (n = 21 males, 28.2 ± 4.7 years old) in association with the rate of lactate accumulation during cycling. Correlation of metabolite values with lactate accumulation has revealed metabolic adaptations that occur in conjunction with improved endurance capacity. In this population, cycling induced increases in tricarboxylic acid (TCA) cycle metabolites and Coenzyme A precursors. These responses occurred proportionally to lactate accumulation, suggesting a link between enhanced mitochondrial networks and the ability to sustain higher workloads. In association with lactate accumulation, altered levels of amino acids before and after exercise point to adaptations that confer unique substrate preference for energy production or to promote more rapid recovery. Cyclists with slower lactate accumulation also have higher levels of basal oxidative stress markers, suggesting long term physiological adaptations in these individuals that support their premier competitive status in worldwide competitions.
... Because these samples were taken from the same elite professional cyclists during a weeklong training camp prior to the season, they enable a paired comparison of molecular profiles as a function of exertion and define blood profiles of humans performing at optimal capacity. Metabolite profiles of the GXT demonstrated characteristic accumulations of circulating lactate, a biomarker of performance capacity that has been traditionally used to guide training exercise (San-Millán et al., 2009. In addition, we were able to quantify the extent to which upstream glycolytic intermediates are modulated to sustain lactate production. ...
... After a 15-minute warm-up, participants started leg cycling at a low intensity of 2.0 W·kg -1 of body weight. Exercise intensity was increased 0.5 W·kg -1 every 10 minutes as previously described (San-Millán et al., 2009) Power output, heart rate and lactate were measured throughout the entire test and recorded every 10 minutes including at the end of the test. The copyright holder for this preprint this version posted September 13, 2022. ...
To characterize molecular profiles of exertion in elite athletes during cycling, we performed metabolomics analyses on blood isolated from twenty-eight international-level elite World Tour professional male athletes from a Union Cycliste Internationale (UCI) World Team taken before and after a graded exercise test (GXT) to volitional exhaustion and before and after a long aerobic training session. Using dried blood spot collection to circumvent logistical hurdles associated with field sampling, these studies defined metabolite signatures and fold change ranges of anaerobic or aerobic exertion in elite cyclists, respectively. Moreover, established signatures were then used to characterize the metabolic physiology of five of these cyclists that were selected to represent the same UCI World Team during a 7-stage elite World Tour race. Collectively, these studies provide a unique view of alterations in the blood metabolome of elite athletes during competition and at the peak of their performance capabilities.
We profiled metabolism of 28 international-level elite World Tour professional male athletes from a Union Cycliste Internationale UCI World Team during training and World Tour multi-stage race;
Dried blood spot sampling affords metabolomics analyses to monitor exercise performance;
Determination of lactate thresholds during graded exercise test (GXT) to volitional exhaustion shows a range of from 3.75 to 6.5 watts per kilogram in this group;
Blood profiles of lactate, carboxylic acids, fatty acids and acylcarnitines differed between different exercise modes (GXT and 180 km aerobic training session);
Metabolic profiles were affected by stage-specific challenges (sprint vs climbing) during a World Tour multi-stage race.
... Compared with those with T2DM and MtS, or even untrained healthy individuals, in trained endurance athletes FATox is far greater during exercise at given absolute and relative exercise intensities [5,, giving rise to superb metabolic flexibility in PAs . Moreover, lactate is a key element for performance, and well-trained athletes have a higher lactate clearance capacity and decreased [La -] levels at the same relative and absolute submaximal exercise intensities [4, owing to mitochondrial abundance and function. This enhanced metabolic function and flexibility makes PAs a very good (if not 'gold standard') model to understand the effect of mitochondrial function on energy substrate partitioning in vivo. ...
... We studied 22 international-level male professional cyclists (PAs), 20 moderately active male individuals (MAs) and 10 male individuals with MtS, who performed graded exercise tests to maximal oxygen consumption (VO 2 max) on a leg cycle ergometer (Lode Excalibur; Lode B.V., Groningen, The Netherlands) . All subjects were given nutritional recommendations ([50% of kcal in the form of CHO) for the night before the test, as well as for the day of the test. ...
Increased muscle mitochondrial mass is characteristic of elite professional endurance athletes (PAs), whereas increased blood lactate levels (lactatemia) at the same absolute submaximal exercise intensities and decreased mitochondrial oxidative capacity are characteristics of individuals with low aerobic power. In contrast to PAs, patients with metabolic syndrome (MtS) are characterized by a decreased capacity to oxidize lipids and by early transition from fat to carbohydrate oxidation (FATox/CHOox), as well as elevated blood lactate concentration [La(-)] as exercise power output (PO) increases, a condition termed 'metabolic inflexibility'.
The aim of this study was to assess metabolic flexibility across populations with different metabolic characteristics.
We used indirect calorimetry and [La(-)] measurements to study the metabolic responses to exercise in PAs, moderately active individuals (MAs), and MtS individuals.
FATox was significantly higher in PAs than MAs and patients with MtS (p < 0.01), while [La(-)] was significantly lower in PAs compared with MAs and patients with MtS. FATox and [La(-)] were inversely correlated in all three groups (PA: r = -0.97, p < 0.01; MA: r = -0.98, p < 0.01; MtS: r = -0.92, p < 0.01). The correlation between FATox and [La(-)] for all data points corresponding to all populations studied was r = -0.76 (p < 0.01).
Blood lactate accumulation is negatively correlated with FATox and positively correlated with CHOox during exercise across populations with widely ranging metabolic capabilities. Because both lactate and fatty acids are mitochondrial substrates, we believe that measurements of [La(-)] and FATox rate during exercise provide an indirect method to assess metabolic flexibility and oxidative capacity across individuals of widely different metabolic capabilities.
... Subjects performed a graded exercise test to exhaustion on a calibrated, electrically braked cycle ergometer (Lode Excalibur Sport, Lode, Groningen, The Netherlands) on day 1. Subjects performed an incremental test according to our protocol, 19 which was slightly modified for this study. The initial workload was 2 W/kg, with increments of 0.5 W/kg every 3 minutes until volitional exhaustion. ...
... 29 Lactate concentration at submaximal exercise intensities has discriminative ability to predict performance in competitive cyclists. 19 Early in recovery, following high-intensity, fixed-load exercise that elicits high blood lactate accumulations, as in our study, enhanced lactate removal may aid recovery by a number of metabolic processes, including facilitating conversion to glucose in the liver and increasing substrate availability for many organs in the body, including the heart, brain, and less active skeletal muscle. 29,30 Various types of active recovery following intense exercise have been shown to improve lactate removal. ...
The purpose of this paper was to assess the feasibility of Micro-Mobile Compression® (MMC) on lactate clearance following exhaustive exercise and on subsequent exercise performance.
Elite male cyclists were randomized to MMC (n = 8) or passive recovery (control, n = 8). MMC is incorporated into a sandal that intermittently compresses the venous plexus during non-weight bearing to augment venous return. On day 1, subjects performed a graded exercise test on a cycle ergometer followed by 60 minutes of seated recovery, with or without MMC. Blood lactate concentration ([La(-)]) was measured during exercise and recovery. Subjects returned home for 3 more hours of seated recovery, with or without MMC. On days 2 and 3, subjects exercised to exhaustion in a fixed-load cycle ergometer test at 85% peak power and then repeated the day 1 post-exercise recovery procedures. Lactate clearance data after the time to exhaustion tests on days 2 and 3 were averaged to adjust for interday variation.
On the day after MMC or control recovery, mean time to exhaustion was 15% longer (mean difference, 2.1 minutes) in the MMC group (P = 0.30). The standardized mean difference of MMC for time to exhaustion was 0.55, defined as a moderate treatment effect. Following the graded exercise test, area under the 60-minute lactate curve was nonsignificantly lower with MMC (3.2 ± 0.4 millimolar [mM]) versus control (3.5 ± 0.4 mM, P = 0.10) and times from end of exercise to 4mM and 2mM were 2.1 minutes (P = 0.58) and 7.2 minutes (P = 0.12) shorter, although neither achieved statistical significance. Following time to exhaustion testing, the area under the 60-minute lactate curve was lower with MMC (3.2 ± 0.2 mM) versus control (3.5 ± 0.2 mM, P = 0.02) and times from end of exercise to 4mM and 2mM were 4.4 minutes (P = 0.02) and 7.6 minutes (P < 0.01) faster. The standardized mean difference of MMC on most lactate clearance parameters was >0.8, defined as a large treatment effect.
MMC yields large treatment effects on lactate clearance following high-intensity exercise and moderate treatment effects on subsequent exercise performance in elite male cyclists.
... Because these samples were taken from the same elite professional cyclists during a 1-week training camp prior to the season, they enable a paired comparison of molecular profiles as a function of exertion and serve to define blood profiles of humans performing at optimal capacity. Metabolite profiles of the GXT demonstrated characteristic accumulations of circulating lactate, a biomarker of performance capacity that has been traditionally used to guide training exercise [19,27]. In addition, we were also able to quantify the extent to which upstream glycolytic intermediates are modulated to sustain lactate production. ...
Background and Objective
Metabolomics studies of recreational and elite athletes have been so far limited to venipuncture-dependent blood sample collection in the setting of controlled training and medical facilities. However, limited to no information is currently available to determine if findings in laboratory settings are translatable to a real-world scenario in elite competitions. The goal of this study was to define molecular signatures of exertion under controlled exercise conditions and use these signatures as a framework for assessing cycling performance in a World Tour competition.
To characterize molecular profiles of exertion in elite athletes during cycling, we performed metabolomics analyses on blood isolated from 28 international-level, elite, World Tour professional male athletes from a Union Cycliste Internationale World Team taken before and after a graded exercise test to volitional exhaustion and before and after a long aerobic training session. Moreover, established signatures were then used to characterize the metabolic physiology of five of these cyclists who were selected to represent the same Union Cycliste Internationale World Team during a seven-stage elite World Tour race.
Using dried blood spot collection to circumvent logistical hurdles associated with field sampling, these studies defined metabolite signatures and fold change ranges of anaerobic or aerobic exertion in elite cyclists, respectively. Blood profiles of lactate, carboxylic acids, fatty acids, and acylcarnitines differed between exercise modes. The graded exercise test elicited significant two- to three-fold accumulations in lactate and succinate, in addition to significant elevations in free fatty acids and acylcarnitines. Conversely, the long aerobic training session elicited a larger magnitude of increase in fatty acids and acylcarnitines without appreciable increases in lactate or succinate. Comparable signatures were revealed after sprinting and climbing stages, respectively, in a World Tour race. In addition, signatures of elevated fatty acid oxidation capacity correlated with competitive performance.
Collectively, these studies provide a unique view of alterations in the blood metabolome of elite athletes during competition and at the peak of their performance capabilities. Furthermore, they demonstrate the utility of dried blood sampling for omics analysis, thereby enabling molecular monitoring of athletic performance in the field during training and competition.
... power) are measured. These values and the manner in which lactate concentration is building up when increasing exercise intensity are good indicators of the performance level of cyclists (San Millán et al. 2009;Wasserman et al. 1981;Karlsson and Jacobs 1982). Typically, at low exercise intensities, the lactate concentration will slowly increase. ...
We present a personalized approach for frequent fitness monitoring in road cycling solely relying on sensor data collected during bike rides and without the need for maximal effort tests. We use competition and training data of three world-class cyclists of Team Jumbo–Visma to construct personalised heart rate models that relate the heart rate during exercise to the pedal power signal. Our model captures the non-trivial dependency between exertion and corresponding response of the heart rate, which we show can be effectively estimated by an exponential kernel. To construct the daily heart rate models that are required for day-to-day fitness estimation, we aggregate all sessions in the previous week and apply sampling. On average, the explained variance of our models is 0.86, which we demonstrate is more than twice as large as for models that ignore the temporal integration involved in the heart’s response to exercise. We show that the fitness of a cyclist can be monitored by tracking developments of parameters of our heart rate models. In particular, we monitor the decay constant of the kernel involved, and also analytically determine virtual aerobic and anaerobic thresholds. We demonstrate that our findings for the virtual anaerobic threshold on average agree with the results of exercise tests. We believe this work is an important step forward in performance optimization by opening up avenues for switching to adaptive training programs that take into account the current physiological state of an athlete.
... We believe that in muscle mitochondria, lactate is oxidized through a complex we call mitochondrial lactate oxidation complex, comprising monocarboxylate transporter-1 (MCT1), its cell surface chaperone (CD147), mitochondrial lactate dehydrogenase (mLDH) and cytochrome oxidase (COx) (Figure 1) (23,146). Because of the stimulus from training, well trained endurance athletes have the most developed mitochondrial capacity characterized by an increased lactate clearance and oxidation of any humans (147,148). ...
Herein we use lessons learned in exercise physiology and metabolism to propose that augmented lactate production ("lactagenesis)", initiated by gene mutations, is the reason and purpose of the Warburg effect and that dysregulated lactate metabolism and signaling are key elements in carcinogenesis. Lactate producing ("lactagenic") cancer cells are characterized by increased aerobic glycolysis and excessive lactate formation, a phenomenon described by Otto Warburg 93 years ago, which still remains unexplained. After a hiatus of several decades, interest in lactate as a player in cancer has been renewed. In normal physiology, lactate, the obligatory product of glycolysis, is an important metabolic fuel energy source, the most important gluconeogenic precursor, and a signaling molecule (i.e., a "lactormone") with major regulatory properties. In lactagenic cancers, oncogenes and tumor suppressor mutations behave in a highly orchestrated manner, apparently with the purpose of increasing glucose utilization for lactagenesis purposes and lactate exchange between, within and among cells. Five main steps are identified: (1) increased glucose uptake, (2) increased glycolytic enzyme expression and activity, 3) decreased mitochondrial function, (4) increased lactate production, accumulation and release, and 5) upregulation of monocarboxylate transporters MTC1 and MCT4 for lactate exchange. Lactate is probably the only metabolic compound involved and necessary in all main sequela for carcinogenesis, specifically: angiogenesis, immune escape, cell migration, metastasis and self-sufficient metabolism. We hypothesize that lactagenesis for carcinogenesis is the explanation and purpose of the Warburg effect. Accordingly, therapies to limit lactate exchange and signaling within and among cancer cells should be priorities for discovery.
... One week later, participants performed a steady-state graded exercise test on the same cycle ergometer. After a warm-up of 10 min at 2 W kg −1 , the exercise protocol began at 2.5 W kg −1 and the load was then increased in steps of 0.5 W kg −1 every 10 min, until exhaustion . After the tests, the participants were recommended to sit down or walk slowly for 90 min. ...
... After a warm-up of 10 min at 2 W/kg, the test began at an initial workload of 2.5 W/kg and continued with increments of 0.5 W/kg every 10 min until exhaustion. This protocol has been used previously with amateur and elite road cyclists by San Millán et al. (2009) . In order to start the test well hydrated, each participant drank 4 mL/kg of water 2 h before the exercise. ...
In this study, we examined the relationship between plasma magnesium levels and hormonal variations during an incremental exercise test until exhaustion in 27, well-trained, male endurance athletes. After a warm-up of 10 min at 2 W/kg, the test began at an initial workload of 2.5 W/kg and continued with increments of 0.5 W/kg every 10 min until exhaustion. Plasma magnesium, catecholamine, insulin, glucagon, parathyroid hormone (PTH), calcitonin, aldosterone and cortisol levels were determined at rest, at the end of each stage and three, five and seven minutes post-exercise. With the incremental exercise test, no variations in plasma magnesium levels were found, while plasma adrenaline, noradrenaline, PTH, glucagon and cortisol levels increased significantly. Over the course of the exercise, plasma levels of insulin decreased significantly, but those of calcitonin remained steady. During the recovery period, catecholamines and insulin returned to basal levels. These findings indicate that the magnesium status of euhydrated endurance athletes during incremental exercise testing may be the result of the interrelation between several hormonal variations.
... After a warm up of 10 min at 2 W·kg -1 , the test began at an initial workload of 2.5 W·kg -1 and continued with increments of 0.5 W·kg -1 every 10 min until exhaustion. This protocol has been used previously with amateur and elite road cyclists by San Millán et al. . In order to start the test well hydrated, each subject drank 4 mL·kg -1 of water 2 h before the exercise, and, in addition, to remain hydrated, each subject drank around 0.8 L·h -1 of water ad libitum  . ...
The purpose of this study was to assess the effect of exercise intensity during an incremental exercise test on plasma Mg concentration in well-trained euhydrated athletes. Twenty-seven well-trained endurance athletes carried out a cycloergometer test: after a warm-up of 10 min at 2.0 W·kg(-1), the workload increased by 0.5 W·kg(-1) every 10 min until exhaustion. Oxygen uptake (VO(2)), blood lactate concentration ([La(-)](b)), catecholamines, and plasma Mg were measured at rest, at the end of each stage and at 3, 5 and 7 minutes post-exercise. Urine specific gravity (U(SG)) was analyzed before and after the test, and subjects drank water ad libitum. Fat oxidation rate (FAT(oxr)), carbohydrate oxidation rate (CHO(oxr)), energy expenditure from fat (EE(FAT)), energy expenditure from carbohydrate (EE(CHO)), and total EE (EE(TOTAL)) were estimated using stoichiometric equations. Plasma Mg concentration at each relative exercise intensity (W·kg(-1)) were compared by means of repeated-measures ANOVA. Pearson's correlations were performed to assess the relationship between variables. The significance level was set at p<0.05. No significant differences were found in U(SG) between before and after the test (1.014±0.004 vs 1.014±0.004 g·cm(-3)). Nor were significant differences found in plasma Mg as a function of the different exercise intensities. Further, no significant correlations were detected between Mg and metabolic variables. In conclusion, acute exercise at a range of submaximal intensities in euhydrated well-trained endurance athletes does not affect plasma Mg concentration, suggesting that the plasma volume plays an important role in Mg homeostasis during exercise.
The field of sports medicine and performance has undergone an important transformation in the past years where the scientific approach is becoming increasingly more important for teams and athletes. Physical and physiological fitness, nutrition, fatigue and recovery, as well as injury prevention are key elements of the scientific monitoring of athletes nowadays. Many different methods are used nowadays as part of the scientific monitoring and testing of the competitive athlete. Among them, physiological and metabolic testing, biomechanical and movement assessments, GPS-based tracking systems, heart rate monitors, power meters, and training software are an integrative part of the scientific monitor program of many teams and athletes.
The purpose of this study was to assess the effect of relative exercise intensity on various plasma trace elements in euhydrated endurance athletes. Twenty-seven well-trained endurance athletes performed a cycloergometer test: after a warm-up of 10 min at 2.0 W kg⁻¹, workload increased by 0.5 W kg⁻¹ every 10 min until exhaustion. Oxygen uptake, blood lactate concentration ([La⁻](b)), and plasma ions (Zn, Se, Mn and Co) were measured at rest, at the end of each stage, and 3, 5 and 7 min post-exercise. Urine specific gravity (U(SG)) was measured before and after the test, and subjects drank water ad libitum. Fat oxidation (FAT(OXR)), carbohydrate oxidation (CHO(OXR)), energy expenditure from fat (EE(FAT)), from carbohydrates (EE(CHO)) and total EE (EE(T)) were estimated using stoichiometric equations. A repeated measure (ANOVA) was used to compare plasma ion levels at each exercise intensity level. The significance level was set at P<0.05. No significant differences were found in U(SG) between, before, and after the test (1.014±0.004 vs. 1.014±0.004 g cm⁻³) or in any plasma ion level as a function of intensity. There were weak significant correlations of Zn (r=0.332, P<0.001) and Se (r=0.242, P<0.01) with [La⁻](b), but no relationships were established between [La⁻](b), VO₂, FAT(OXR), CHO(OXR), EE(FAT), EE(CHO), or EE(T) and plasma ion levels. Acute exercise at different submaximal intensities in euhydrated well-trained endurance athletes does not provoke a change in plasma trace element levels, suggesting that plasma volume plays an important role in the homeostasis of these elements during exercise.