Matthieu Clauss

• Clauss, Matthieu; Bukhardt, Meike; Wøber, Sophie; Skålhegg, Bjørn Steen & Jensen, Jørgen (2024). Effect of five hours of mixed exercise on urinary nitrogen excretion in healthy moderate-to-well-trained young adults. Frontiers in Nutrition. ISSN 2296-861X. 11, p. 1–11. doi: 10.3389/fnut.2024.1345922.
• Clauss, Matthieu; Skattebo, Øyvind; Rasen Dæhli, Malin; Valsdottir, Thorhildur Ditta; Bastani, Nasser Ezzatkhah & Johansen, Egil Ivar [Show all 9 contributors for this article] (2023). Carbohydrate Ingestion during Prolonged Cycling Improves Next-Day Time Trial Performance and Alters Amino Acid Concentrations. Medicine & Science in Sports & Exercise. ISSN 0195-9131. 55(12), p. 2228–2240. doi: 10.1249/MSS.0000000000003264.
• Fenne, Karoline Tusvik; Clauss, Matthieu; Olstad, Daniela Schäfer; Johansen, Egil Ivar & Jensen, Jørgen (2023). An Acute Bout of Endurance Exercise Does Not Prevent the Inhibitory Effect of Caffeine on Glucose Tolerance the following Morning. Nutrients. ISSN 2072-6643. 15(8). doi: 10.3390/nu15081941. Full text in Research Archive Show summary

  Caffeine reduces glucose tolerance, whereas exercise training improves glucose homeostasis. The aim of the present study was to investigate the effect of caffeine on glucose tolerance the morning after an acute bout of aerobic exercise. Methods: The study had a 2 × 2 factorial design. Oral glucose tolerance tests (OGTT) were performed after overnight fasting with/without caffeine and with/without exercise the evening before. Eight healthy young active males were included (Age 25.5 ± 1.5 years; 83.9 ± 9.0 kg; VO2max: 54.3 ± 7.0 mL·kg−1·min−1). The exercise session consisted of 30 min cycling at 71% of VO2max followed by four 5 min intervals at 84% with 3 min of cycling at 40% of VO2max between intervals. The exercise was performed at 17:00 h. Energy expenditure at each session was ~976 kcal. Lactate increased to ~8 mM during the exercise sessions. Participants arrived at the laboratory the following morning at 7.00 AM after an overnight fast. Resting blood samples were taken before blood pressure and heart rate variability (HRV) were measured. Caffeine (3 mg/kg bodyweight) or placebo (similar taste/flavor) was ingested, and blood samples, blood pressure and HRV were measured after 30 min. Next, the OGTTs were initiated (75 g glucose dissolved in 3 dL water) and blood was sampled. Blood pressure and HRV were measured during the OGTT. Caffeine increased the area under curve (AUC) for glucose independently of whether exercise was done the evening before (p = 0.03; Two-way ANOVA; Interaction: p = 0.835). Caffeine did not significantly increase AUC for C-peptides compared to placebo (p = 0.096), and C-peptide response was not influenced by exercise. The acute bout of exercise did not significantly improve glucose tolerance the following morning. Diastolic blood pressure during the OGTT was slightly higher after intake of caffeine, independent of whether exercise was performed the evening before or not. Neither caffeine nor exercise the evening before significantly influenced HRV. In conclusion, caffeine reduced glucose tolerance independently of whether endurance exercise was performed the evening before. The low dose of caffeine did not influence heart rate variability but increased diastolic blood pressure slightly.

• Sollie, Ove; Clauss, Matthieu; Jeppesen, Per Bendix; Tangen, Daniel S.; Johansen, Egil Ivar & Skålhegg, Bjørn Steen [Show all 8 contributors for this article] (2023). Similar performance after intake of carbohydrate plus whey protein and carbohydrate only in the early phase after non-exhaustive cycling. Scandinavian Journal of Medicine & Science in Sports. ISSN 0905-7188. 33(7), p. 1091–1103. doi: 10.1111/sms.14364. Full text in Research Archive Show summary

  Aim: The aim of the present study was to compare performance 5 h after a 90-min endurance training session when either carbohydrate only or carbohydrate with added whey hydrolysate or whey isolate was ingested during the first 2 h of the recovery period. Methods: Thirteen highly trained competitive male cyclists completed three exercise and diet interventions (double-blinded, randomized, crossover design) separated by 1 week. The 90-min morning session (EX1) included a 60 min time-trial (TT60). Immediately and 1 h after exercise, participants ingested either (1) 1.2 g carbohydrate∙kg−1∙h−1 (CHO), (2) 0.8 g carbohydrate∙kg−1∙h−1 + 0.4 g isolate whey protein∙kg−1∙h−1 (ISO) or (3) 0.8 g carbohydrate∙kg−1∙h−1 + 0.4 g hydrolysate whey protein∙kg−1∙h−1 (HYD). Additional intakes were identical between interventions. After 5 h of recovery, participants completed a time-trial performance (TTP) during which a specific amount of work was performed. Blood and urine were collected throughout the day. Results: TTP did not differ significantly between dietary interventions (CHO: 43:54 ± 1:36, ISO: 46:55 ± 2:32, HYD: 44:31 ± 2:01 min). Nitrogen balance during CHO was lower than ISO (p < 0.0001) and HYD (p < 0.0001), with no difference between ISO and HYD (p = 0.317). In recovery, the area under the curve for blood glucose was higher in CHO compared to ISO and HYD. HR, VO2, RER, glucose, and lactate during EX2 were similar between interventions. Conclusion: Performance did not differ after 5 h of recovery whether carbohydrate only or isocaloric carbohydrate plus protein was ingested during the first 2 h. Correspondingly, participants were not in negative nitrogen balance in any dietary intervention.

• Fabre, Marina; Mathieu, Bertrand; Tiollier, Eve; Leduc, Cedric; Clauss, Matthieu & Marchand, Alexandre [Show all 13 contributors for this article] (2022). Effects of Native Whey Protein and Carbohydrate Supplement on Physical Performance and Plasma Markers of Muscle Damage and Inflammation during a Simulated Rugby Sevens Tournament: A Double-Blind, Randomized, Placebo-Controlled, Crossover Study. Nutrients. ISSN 2072-6643. 14.
• Skattebo, Øyvind; Peci, Dafina; Clauss, Matthieu; Johansen, Egil Ivar & Jensen, Jørgen (2022). Increased Mass-Specific Maximal Fat Oxidation Rate with Small versus Large Muscle Mass Exercise. Medicine & Science in Sports & Exercise. ISSN 0195-9131. 54(6), p. 974–983. doi: 10.1249/MSS.0000000000002864. Full text in Research Archive Show summary

  Introduction: Skeletal muscle perfusion and oxygen (O2) delivery are restricted during whole-body exercise due to a limited cardiac output (Q[Combining Dot Above]). This study investigated the role of reducing central limitations to exercise on the maximal fat oxidation rate (MFO) by comparing mass-specific MFO (per kg active lean mass) during one-legged (1 L) and two-legged (2 L) cycling. We hypothesized that the mass-specific MFO would be higher during 1 L- than 2 L cycling. Methods: Twelve male subjects (V[Combining Dot Above]O2peak: 59.3 ± 8.4 mL·kg-1·min-1; mean ± SD) performed step-incremental 2 L- (30-80% of V[Combining Dot Above]O2peak) and 1 L (50% of 2 L power output, i.e., equal power output per leg) cycling (counterbalanced) while steady-state pulmonary gas exchanges, Q[Combining Dot Above] (pulse-contour analysis), and skeletal muscle (vastus lateralis) oxygenation (near-infrared spectroscopy) were determined. MFO and the associated power output (FatMax) were calculated from pulmonary gas exchanges and stoichiometric equations. A counterweight (10.9 kg) was added to the contralateral pedal arm during 1 L cycling. Leg lean mass was determined by DEXA. Results: The absolute MFO was 24% lower (0.31 ± 0.12 vs 0.44 ± 0.20 g·min-1; P = 0.018) while mass-specific MFO was 52% higher (28 ± 11 vs 20 ± 10 mg·min-1·kg-1; P = 0.009) during 1 L- than 2 L cycling. FatMax was similar expressed as power output per leg (60 ± 28 vs 58 ± 22 W; P = 0.649). Q· increased more from rest to exercise during 1 L- than 2 L cycling when expressed per active leg (ANOVA main effect: P = 0.003). The tissue oxygenation index and Δ[deoxy(Hb + Mb)] were not different between exercise modes (ANOVA main effects: P ≥ 0.587), indicating similar skeletal muscle fractional O2 extraction. Conclusions: Mass-specific MFO is increased by exercising a small muscle mass, potentially explained by increased perfusion and more favorable conditions for O2 delivery than during whole-body exercise.

• Clauss, Matthieu; Gérard, Philippe; Mosca, Alexis & Leclerc, Marion (2021). Interplay Between Exercise and Gut Microbiome in the Context of Human Health and Performance. Frontiers in Nutrition. ISSN 2296-861X. 8. doi: 10.3389/fnut.2021.637010. Full text in Research Archive Show summary

  Gut microbiota and exercise have recently been shown to be interconnected. Both moderate and intense exercise are typically part of the training regimen of endurance athletes, but they exert different effects on health. Moderate exercise has positive effects on the health of average athletes, such as a reduction in inflammation and intestinal permeability and an improvement in body composition. It also induces positive changes in the gut microbiota composition and in the microbial metabolites produced in the gastrointestinal tract. Conversely, intense exercise can increase gastrointestinal epithelial wall permeability and diminish gut mucus thickness, potentially enabling pathogens to enter the bloodstream. This, in turn, may contribute to the increase in inflammation levels. However, elite athletes seem to have a higher gut microbial diversity, shifted toward bacterial species involved in amino acid biosynthesis and carbohydrate/fiber metabolism, consequently producing key metabolites such as short-chain fatty acids. Moreover, rodent studies have highlighted a bidirectional relationship, with exercise impacting the gut microbiota composition while the microbiota may influence performance. The present review focuses on gut microbiota and endurance sports and how this interconnection depends upon exercise intensity and training. After pointing out the limits of the studies so far available, we suggest that taking into account the microbiota composition and its metabolic contribution to human host health could help in monitoring and modulating athletes' health and performance. Such an integrated approach should help in the design of microbiome-based solutions for health or performance.

• Olsen, Thomas; Sollie, Ove; Nurk, Eha; Turner, Cheryl; Jernerén, Fredrik & Ivy, John L. [Show all 10 contributors for this article] (2020). Exhaustive Exercise and Post-exercise Protein Plus Carbohydrate Supplementation Affect Plasma and Urine Concentrations of Sulfur Amino Acids, the Ratio of Methionine to Homocysteine and Glutathione in Elite Male Cyclists. Frontiers in Physiology. ISSN 1664-042X. doi: 10.3389/fphys.2020.609335. Full text in Research Archive Show summary

  Plasma and tissue sulfur amino acid (SAA) availability are crucial for intracellular methylation reactions and cellular antioxidant defense, which are important processes during exercise and in recovery. In this randomized, controlled crossover trial among eight elite male cyclists, we explored the effect of exhaustive exercise and post-exercise supplementation with carbohydrates and protein (CHO+PROT) vs. carbohydrates (CHO) on plasma and urine SAAs, a potential new marker of methylation capacity (methionine/total homocysteine ratio [Met/tHcy]) and related metabolites. The purpose of the study was to further explore the role of SAAs in exercise and recovery. Athletes cycled to exhaustion and consumed supplements immediately after and in 30 min intervals for 120 min post-exercise. After ~18 h recovery, performance was tested in a time trial in which the CHO+PROT group cycled 8.5% faster compared to the CHO group (41:53 ± 1:51 vs. 45:26 ± 1:32 min, p

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• Clauss, Matthieu; Burkhardt, Meike; Wöber, Sophie; Skålhegg, Bjørn Steen & Jensen, Jørgen (2024). Corrigendum: Effect of five hours of mixed exercise on urinary nitrogen excretion in healthy moderate-to-well-trained young adults, (Front. Nutr, (2024), 11, (1345922), 10.3389/fnut.2024.1345922). Frontiers in Nutrition. ISSN 2296-861X. 11. doi: 10.3389/fnut.2024.1406641.

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