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Introduction. Human metabolism is highly ariable. At the pathological end, inborn or acquired defects cause metabolic disease and systematically alter blood metabolites. Physiologically, genetic predisposition and years of training result in a highly anabolic, glycolytic or oxidative metabolism. We aimed to investigate whether years of aerobic, resistance or sprint training, resulting in physiological extremes of human metabolism systematically change blood metabolites.Methods. We recruited 35 healthy male subjects, 9 natural bodybuilders, 8 sprinters, 11 endurance athletes and 7 untrained controls. We phenotyped participants according to endurance performance, strength, and anthropometry. We drew blood at fasted rest and 5 minutes after a cycle ergometry to exhaustion and profiled 857 metabolites by untargeted metabolomics.Results. Multivariate analysis revealed that endurance athletes and natural bodybuilders years of training differentially shapes their blood metabolome at rest and after exercise, whereas sprinters and controls shared similarities. Endurance athletes and natural bodybuilders have lower levels of sulfated steroids compared to sprinters and controls and higher levels of sphingomyelins and long-chain polyunsaturated fatty acids. Endurance athletes showed higher concentrations of long-chain saturated acylcarnitines than bodybuilders, suggesting acutely higher oxidation rates during exercise or a higher capacity to mobilize. Natural bodybuilders have higher levels of amino acids mainly such involved in histidine metabolism. While we observed changes of known exercise metabolitessuch as lactate, pyruvate and hypoxanthine in all groups, we found significant differences in the responsiveness to exercise between each athlete group versus controls (e.g. acylcarnitines, dopamine metabolites).Discussion. We confirmed findings of our targeted metabolomics that highly anabolic and oxidative athletes have sysematically changed blood metabolite concentrations, c

Resistance training promotes metabolic health and stimulates muscle hypertrophy, but the precise routes by which resistance exercise (RE) conveys these health benefits is largely unknown. Aim: To investigate how acute RE affects human skeletal muscle metabolism. Methods: We collected vastus lateralis biopsies from six healthy male untrained volunteers at rest, before the first of 13 RE training sessions, and 45 min after the first and last bouts of RE. Biopsies were analysed using untargeted mass spectrometry-based metabolomics. Results: We measured 617 metabolites covering a broad range of metabolic pathways. In the untrained state RE altered 33 metabolites, including increased 3-methylhistidine and N-lactoylvaline, suggesting increased protein breakdown, as well as metabolites linked to ATP (xanthosine) and NAD (N1-methyl-2-pyridone-5-carboxamide) metabolism; the bile acid chenodeoxycholate also increased in response to RE in muscle opposing previous findings in blood. Resistance training led to muscle hypertrophy, with slow type I and fast/intermediate type II muscle fibre diameter increasing by 10.7% and 10.4%, respectively. Comparison of post-exercise metabolite levels between trained and untrained state revealed alterations of 46 metabolites, including decreased N-acetylated ketogenic amino acids and increased beta-citrylglutamate which might support growth. Only five of the metabolites that changed after acute exercise in the untrained state were altered after chronic training, indicating that training induces multiple metabolic changes not directly related to the acute exercise response. Conclusion: The human skeletal muscle metabolome is sensitive towards acute RE in the trained and untrained states and reflects a broad range of adaptive processes in response to repeated stimulation.

Introduction. Mouse studies suggest that exercise can promote white adipocyte browning by increasing the expression of UCP1, a gene that encodes the protein responsible for non-shivering thermogenesis. In humans, however, there is limited evidence that exercise can promote UCP1 expression in white adipocytes. The aim of this study was therefore to use a novel human serum on human white adipocyte assay to study the effects of exercise on UCP1 expression in white adipocytes. Method. To study exercise-induced browning of primary human subcutaneous white adipocytes, we obtained whole blood samples from 7 untrained controls, 9 natural bodybuilders, 8 sprinters, and 11 endurance athletes at fasted rest and after a graded cycle ergometry test to subjective exhaustion. From whole-blood, we generated serum which we used at a 10% v/v dilution to treat differentiated, primary human subcutaneous white adipocytes (purchased from Zen-Bio) for 16 h. We then isolated total RNA with Trizol and measured UCP1 mRNA by RT-qPCR.Results. In untrained controls, exercise-conditioned sera increased UCP1 expression significantly by 40% when compared to resting sera. In contrast, the exercise-conditioned sera of natural bodybuilders, sprinters and endurance athletes increase UCP1 expression by 124%, 185%, and 112%, respectively. Despite the mean increase, individual athlete responses included non-responders, average responders, and superresponders in all athlete groups. Discussion. In this study, we report a novel, minimally invasive human serum on human white adipocyte assay to assess white adipocyte browning (i.e. UCP1 expression). Using this assay to study the effect of exercise on browning revealed that exercise increased mean UCP1 expression in all groups. Some athletes were super-responders as their post exercise sera increased UCP1 expression by more than 200% when compared to sera taken at rest.

Introduction Resistance training is an effective intervention to increase muscle mass and function in athletes and patients (Colberg et al., 2016). Whilst we know much about how resistancetraining increases skeletal muscle mass, we poorly understand the underlying mechanism of metabolic adaptations when muscle hypertrophies. The aim of this study was therefore to investigate the effect of insulin-like growth factor (Igf)-1-stimulated C2C12 myotube hypertrophy on the muscle metabolome. Methods C2C12 cells were cultured and differentiated to myotubes using standard tissue culture techniques (Watt et al., 2010). Three days after initiation of differentiation, cells were treated with vehicle (control; VC), Igf-1 (100 ng/mL; IGF) or Rapamycin (10 ng/mL; RAP) for 48 h. Metabolites were extracted in 80% methanol and then analysed with liquid chromatography-tandem mass spectrometry. Data were analysed using a Student’s t-test for metabolite concentration. A false discovery rate (FDR) of < 0.2 was used to correct for multiple testing. Results Muscle growth stimulation increased lactic acid production in IGF compared to VC (198-306%; FDR = 0.09) and RAP (608-1,222%; FDR = 0.04). IGF increased concentrations of pentose phosphate pathway metabolites (e. g. Ribose 5-phosphate) as well as 13 amino acids (AA) when compared to VC and RAP (all FDR < 0.2), respectively. Discussion Our data suggest that Igf-1-stimulated C2C12 myotube hypertrophy is associated with increased glycolytic and pentose phosphate pathway flux. An increased rate of aerobic glycolysis is a sign for the Warburg effect by which healthy and cancerous, proliferating cells reprogram their metabolism to generate substrates for anabolic reactions. The results here suggest that a similar metabolic reprogramming also occurs during muscle hypertrophy.

Einleitung Chirurgische und FFP2-Masken reduzieren die SARS-CoV-2-Infektionsgefahr. Bei körperlicher Belastung kann jedoch die Ventilation von 5-10 l/min in Ruhe bis zu 200 l/min bei Leistungssportlern ansteigen und die Maske wird dann bei der Ausatmung wie ein Segel vom Gesicht geblasen. Um dies zu vermeiden wurde eine Klebe-Filtermaske entwickelt. Das Ziel dieser Studie war es bei körperlicher Belastung eine Klebe-Filtermaske mit einer chirurgischen Maske und keiner Maske zu vergleichen. Methode Vier Frauen und vier Männer im Alter von 24.5 ± 3.3 Jahren führten einen abgestuften Belastungstest bis zur subjektiven Erschöpfung unter drei Bedingungen durch: (1) Keine Maske (Kontrolle), (2) chirurgische Maske und (3) Klebe-Filtermaske. Während dieser Tests wurden das Empfinden von Atemnot, die Herzfrequenz, die Laktatkonzentration im Blut und die periphere Sauerstoffsättigung gemessen und die resultierenden Daten mit ein- oder zweiseitigen ANOVAs mit wiederholten Messungen analysiert. Außerdem wurde ein Fragebogen zur Bewertung des Maskenkomforts beantwortet. Ergebnisse Im Vergleich zu einer Belastung ohne Maske war die maximale Belastung mit einer KlebeFiltermaske signifikant um 12 ± 6% (p < 0.001) und mit einer chirurgischen Maske um 3 ± 6% (p > 0.05) reduziert. Die Sauerstoffsättigung bei 65 % der maximalen Belastung war mit einer Klebe-Maske um 1,5 % niedriger (p = 0.018) als ohne Maske. Herzfrequenz und die Laktatkonzentration im Blut unterscheiden sich bei keiner Belastung signifikant. Im Vergleich zum Tragen einer chirurgischen Maske hat das Tragen einer abgeklebten Filtergesichtsmaske einen signifikant besseren Tragekomfort (p = 0.038), fühlt sich besser auf der Haut an (p = 0.004), es besteht ein geringeres Feuchtigkeitsgefühl (p = 0.026) und die Träger nehmen eine geringere Wärmeentwicklung wahr (p = 0.021). Wir fanden keine Unterschiede zwischen den Geschlechtern bei allen Parametern. Diskussion Eine Klebe-Filtermaske wird bei leichter und mittlerer Trainin

Dried blood spots (DBS) are an alternative sampling method to blood plasma sampling. In contrast to blood plasma sampling, DBS are low-volume capillary blood samples obtained via pricking and collection on paper cards. DBS require less space and no cooling which is advantageous for exercise tests in the field. The aim of this project was to compare metabolite concentration measurements of DBS and blood plasma samples. Moreover, we investigated the effects of acute exercise in women and men. Methods DBS and blood plasma samples were collected from 28 fasted volunteers (13 female, age 24.9 ± 1.99 years) from the earlobe. Samples were taken at rest and directly after a graded-exercise test to exhaustion on a bicycle ergometer. Metabolite concentrations of 43 amino acids and acylcarnitines were measured via flow-injection analysis tandem mass spectrometry. Results All amino acids and 13 out of 30 acylcarnitines were quantified in the accepted LOD range (> 80% of samples) and included in further analyses. Absolute metabolite concentrations were significantly higher in blood plasma samples for 20 out of 26 remaining analytes when compared to DBS. Principal component analysis indicated a strong association between sampling method and the observed variation in our data. Correlations between DBS and blood plasma metabolite concentrations for the metabolites ranged between r = -0.107 for aspartate and r = 0.983 for octanoyl carnitine (0.587 ≥ p ≥ 0.001, n = 28). Linear regression revealed a proportional bias for 19, a systematic bias in eleven, and no bias in six out of 26 metabolites. To test for the influence of gender and exercise, we performed a two-factor repeated measures ANOVA which yielded differential results for each sampling method. In blood plasma, significant effects could be shown for 10 analytes by exercise and 4 by gender. In contrast, DBS has elucidated 23 changed metabolites by exercise and differences in gender in 10. Overall, exercise significantly changed

Introduction A growing number of portable devices has become available to quantify activities of daily living monitoring heart-rate (HR) and/or acceleration (ACC). Using these data, it is possible to estimate energy expenditure (EE). A linear relationship has been reported between EE and body acceleration in walking. Although there are different kinds of studies related to HR, ACC and EE, no one used an ear sensor before. This study assessed the validity of novel ear sensors and compared the outcome to mobile spirometry estimating EE. Methods Nineteen healthy male and female participants (age 26.4 ± 3.4, body mass 69.5 ± 9.8) performed one lab test consisted of a standard treadmill test (Modified Bruce Protocol) and an outdoor walking test (1 kilometre) at moderate and maximal walking speeds up- and downhill. As reference, EE was measured by a mobile spiroergometry device (MetaMax 3B-3X, Cortex) based on the Bouwer Equation (using O2 and CO2), whereas HR and ACC, were measured continuously by cosinuss° ear sensors one and two. Validity of the methods used to estimate EE was compared using Pearson correlations, and a regression model was conducted based on the lab session, and root mean squared error (RMSE) from cross-validation at the individual and population levels. Results A mixed-model analysis identified HR and ACC as factors that best predicted the relationship between HR, ACC, and EE. The model (with the highest likelihood ratio) was used to estimate energy expenditure. The correlation coefficient (r) between the measured and estimated energy expenditure was 0.789 whilst the (r) between magnitude vector and energy expenditure was 0.971. The model therefore accounted for 98.4% (r2) of the variance in EE in this sample. The linear regression equation for changes in HR showed the highest coefficient of determination (r2) of 0.984 with an F < 0.05, while the linear regression equation for changes in magnitude vector showed a coefficient of determination (r2) of 0