BRYAN SAUNDERS
Projetos de Pesquisa
Unidades Organizacionais
LIM/17 - Laboratório de Investigação em Reumatologia, Hospital das Clínicas, Faculdade de Medicina
15 resultados
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- Directions for Future Studies to Determine Dietary Nitrate Efficacy in Female Athletes(2023) CARVALHO, Arthur; DUARTE, Breno; ELLIOTT-SALE, Kirsty Jayne; SAUNDERS, Bryan
- Can I Have My Coffee and Drink It? A Systematic Review and Meta-analysis to Determine Whether Habitual Caffeine Consumption Affects the Ergogenic Effect of Caffeine(2022) CARVALHO, Arthur; MARTICORENA, Felipe Miguel; GRECCO, Beatriz Helena; BARRETO, Gabriel; SAUNDERS, BryanObjective The aim was to quantify the proportion of the literature on caffeine supplementation that reports habitual caffeine consumption, and determine the influence of habitual consumption on the acute exercise response to caffeine supplementation, using a systematic review and meta-analytic approach. Methods Three databases were searched, and articles screened according to inclusion/exclusion criteria. Three-level meta-analyses and meta-regression models were used to investigate the influence of habitual caffeine consumption on caffeine's overall ergogenic effect and within different exercise types (endurance, power, strength), in men and women, and in trained and untrained individuals. Sub-analyses were performed according to the following: acute relative dose (< 3, 3-6, > 6 mg/kg body mass [BM]); whether the acute caffeine dose provided was lower or higher than the mean daily caffeine dose; and the caffeine withdrawal period prior to the intervention (< 24, 24-48, > 48 h). Results Sixty caffeine studies included sufficient information on habitual consumption to be included in the meta-analysis. A positive overall effect of caffeine was shown in comparison to placebo (standard mean difference [SMD] = 0.25, 95% confidence interval [CI] 0.20-0.30; p < 0.001) with no influence of relative habitual caffeine consumption (p = 0.59). Subgroup analyses showed a significant ergogenic effect when the caffeine dose was < 3 mg/kg BM (SMD = 0.26, 95% CI 0.12-0.40; p = 0.003) and 3-6 mg/kg BM (SMD = 0.26, 95% CI 0.21-0.32; p < 0.0001), but not > 6 mg/kg BM (SMD = 0.11, 95% CI - 0.07 to 0.30; p = 0.23); when the dose was both higher (SMD = 0.26, 95% CI 0.20-0.31; p < 0.001) and lower (SMD = 0.21, 95% CI 0.06-0.36; p = 0.006) than the habitual caffeine dose; and when withdrawal was < 24 h, 24-48 h, and > 48 h. Caffeine was effective for endurance, power, and strength exercise, with no influence (all p >= 0.23) of relative habitual caffeine consumption within exercise types. Habitual caffeine consumption did not modify the ergogenic effect of caffeine in male, female, trained or untrained individuals. Conclusion Habitual caffeine consumption does not appear to influence the acute ergogenic effect of caffeine.
- The interplay between bicarbonate kinetics and gastrointestinal upset on ergogenic potential after sodium bicarbonate intake: a randomized double-blind placebo-controlled trial(2023) DURKALEC-MICHALSKI, Krzysztof; NOWACZYK, Paulina M.; KAMINSKA, Joanna; SAUNDERS, Bryan; LONIEWSKI, Igor; CZUBASZEK, Dominika; STEFFL, Michal; PODGORSKI, TomaszThis double-blind placebo-controlled cross-over study utilized comprehensive monitoring of blood bicarbonate (HCO3 over bar ) kinetics and evaluation of gastrointestinal (GI) upset to determine their impact on an ergogenic potential of sodium bicarbonate (SB) co-ingested with carbohydrate (CHO). Nineteen CrossFit athletes performed 6 bouts of 15 s Wingate Anaerobic Test (WAnT) 90 min post-ingestion of 0.4 g center dot kg(-1) body mass (BM) of SB (SB + CHO treatment) or PLA (PLA + CHO treatment) with 15 g CHO. Blood HCO3 over bar concentration was evaluated at baseline, 30-, 60-, 75- and 90 min post-ingestion, in between WAnT bouts, and 3 and 45 min post-exercise, while GI upset at 120 min after protocol started. Control (no supplementation; CTRL) procedures were also performed. An effective elevation of extra-cellular buffering capacity was observed 60-90 min post-ingestion of SB + CHO. At mean peak blood HCO3 over bar , or at start of exercise an increase > 6 mmol center dot L-1 in HCO3 over bar was noted in 84% and 52.6% participants, respectively. SB + CHO did not prevent performance decrements in WAnT bouts. There were no significant relationships between changes in blood HCO3 over bar and WAnTs' performance. Total GI was significantly higher in SB + CHO compared to CTRL, and stomach problems in SB + CHO compared to CTRL and PLA + CHO. There were inverse associations between peak- (p = 0.031; r = - 0.495), average- (p = 0.002; r = - 0.674) and minimum power (p = 0.008; r = - 0.585) and total GI upset, as well as average power and severe GI distress (p = 0.042; r = - 0.471) at SB + CHO. The implemented dose of SB + CHO was effective in improving buffering capacity, but did not prevent decrements in WAnTs' performance. GI side effects were crucial in affecting the ergogenic potential of SB and thus must be insightfully monitored in future studies.
- Editorial: Personalized Sport and Exercise Nutrition(2019) SAUNDERS, Bryan; EL-SOHEMY, Ahmed; DERAVE, Wim
- Beta-alanine did not improve high-intensity performance throughout simulated road cycling(2022) PERIM, Pedro; GOBBI, Nathan; DUARTE, Breno; OLIVEIRA, Luana Farias de; COSTA, Luiz Augusto Riani; SALE, Craig; GUALANO, Bruno; DOLAN, Eimear; SAUNDERS, BryanThis study investigated the effect of beta-alanine supplementation on short-duration sprints and final 4-km simulated uphill cycling time-trial performance during a comprehensive and novel exercise protocol representative of the demands of road-race cycling, and determined if changes were related to increases in muscle carnosine content. Seventeen cyclists (age 38 +/- 9 y, height 1.76 +/- 0.07 m, body mass 71.4 +/- 8.8 kg, V?O-2max 52.4 +/- 8.3 ml center dot kg(-1)center dot min(-1)) participated in this placebo-controlled, double-blind study. Cyclists undertook a prolonged intermittent cycling protocol lasting 125 min, with a 10-s sprint every 20 min, finishing with a 4-km time-trial at 5% simulated incline. Participants completed two familiarization sessions, and two main sessions, one pre-supplementation and one post-supplementation following 28 days of 6.4 g center dot day(-1) of beta-alanine (N=11) or placebo (N=6; maltodextrin). Muscle biopsies obtained pre- and post-supplementation were analysed for muscle carnosine content. There were no main effects on sprint performance throughout the intermittent cycling test (all P>0.05). There was no group (P=0.69), time (P=0.50) or group x time interaction (P=0.26) on time-to-complete the 4-km time-trial. Time-to-completion did not change from pre- to post-supplementation for BA (-19.2 +/- 45.6 s, P=0.43) or PL (+2.8 +/- 31.6 s, P=0.99). Beta-alanine supplementation increased muscle carnosine content from pre- to post-supplementation (+9.4 +/- 4.0 mmol center dot kg(-1)dm; P<0.0001) but was not related to performance changes (r=0.320, P=0.37). Chronic beta-alanine supplementation increased muscle carnosine content but did not improve short-duration sprint performance throughout simulated road race cycling, nor 4-km uphill time-trial performance conducted at the end of this cycling test.
- 24-Week beta-alanine ingestion does not affect muscle taurine or clinical blood parameters in healthy males(2020) SAUNDERS, Bryan; FRANCHI, Mariana; OLIVEIRA, Luana Farias de; SILVA, Vinicius da Eira; SILVA, Rafael Pires da; PAINELLI, Vitor de Salles; COSTA, Luiz Augusto Riani; SALE, Craig; HARRIS, Roger Charles; ROSCHEL, Hamilton; ARTIOLI, Guilherme Giannini; GUALANO, BrunoPurpose To investigate the effects of chronic beta-alanine (BA) supplementation on muscle taurine content, blood clinical markers and sensory side-effects. Methods Twenty-five healthy male participants (age 27 +/- 4 years, height 1.75 +/- 0.09 m, body mass 78.9 +/- 11.7 kg) were supplemented with 6.4 g day(-1) of sustained-release BA (N = 16; CarnoSyn (TM), NAI, USA) or placebo (PL; N = 9; maltodextrin) for 24 weeks. Resting muscle biopsies of the m. vastus lateralis were taken at 0, 12 and 24 weeks and analysed for taurine content (BA, N = 12; PL, N = 6) using high-performance liquid chromatography. Resting venous blood samples were taken every 4 weeks and analysed for markers of renal, hepatic and muscle function (BA, N = 15; PL, N = 8; aspartate transaminase; alanine aminotransferase; alkaline phosphatase; lactate dehydrogenase; albumin; globulin; creatinine; estimated glomerular filtration rate and creatine kinase). Results There was a significant main effect of group (p = 0.04) on muscle taurine, with overall lower values in PL, although there was no main effect of time or interaction effect (both p > 0.05) and no differences between specific timepoints (week 0, BA: 33.67 +/- 8.18 mmol kg(-1) dm, PL: 27.75 +/- 4.86 mmol kg(-1) dm; week 12, BA: 35.93 +/- 8.79 mmol kg(-1) dm, PL: 27.67 +/- 4.75 mmol kg(-1) dm; week 24, BA: 35.42 +/- 6.16 mmol kg(-1) dm, PL: 31.99 +/- 5.60 mmol kg(-1) dm). There was no effect of treatment, time or any interaction effects on any blood marker (all p > 0.05) and no self-reported side-effects in these participants throughout the study. Conclusions The current study showed that 24 weeks of BA supplementation at 6.4 g day(-1) did not significantly affect muscle taurine content, clinical markers of renal, hepatic and muscle function, nor did it result in chronic sensory side-effects, in healthy individuals. Since athletes are likely to engage in chronic supplementation, these data provide important evidence to suggest that supplementation with BA at these doses for up to 24 weeks is safe for healthy individuals.
- High-Intensity Interval Training Augments Muscle Carnosine in the Absence of Dietary Beta-alanine Intake(2018) PAINELLI, Vitor De Salles; NEMEZIO, Kleiner Marcio; PINTO, Ana Jessica; FRANCHI, Mariana; ANDRADE, Isabel; RIANI, Luiz Augusto; SAUNDERS, Bryan; SALE, Craig; HARRIS, Roger Charles; GUALANO, Bruno; ARTIOLI, Guilherme GianniniPurpose Cross-sectional studies suggest that training can increase muscle carnosine (MCarn), although longitudinal studies have failed to confirm this. A lack of control for dietary -alanine intake or muscle fiber type shifting may have hampered their conclusions. The purpose of the present study was to investigate the effects of high-intensity interval training (HIIT) on MCarn. Methods Twenty vegetarian men were randomly assigned to a control (CON) (n = 10) or HIIT (n = 10) group. High-intensity interval training was performed on a cycle ergometer for 12 wk, with progressive volume (6-12 series) and intensity (140%-170% lactate threshold [LT]). Muscle carnosine was quantified in whole-muscle and individual fibers; expression of selected genes (CARNS, CNDP2, ABAT, TauT, and PAT1) and muscle buffering capacity in vitro (m(in vitro)) were also determined. Exercise tests were performed to evaluate total work done, VO2max, ventilatory thresholds (VT) and LT. Results Total work done, VT, LT, VO2max, and m(in vitro) were improved in the HIIT group (all P < 0.05), but not in CON (P > 0.05). MCarn (in mmolkg(-1) dry muscle) increased in the HIIT (15.8 5.7 to 20.6 +/- 5.3; P = 0.012) but not the CON group (14.3 +/- 5.3 to 15.0 +/- 4.9; P = 0.99). In type I fibers, MCarn increased in the HIIT (from 14.4 +/- 5.9 to 16.8 +/- 7.6; P = 0.047) but not the CON group (from 14.0 +/- 5.5 to 14.9 +/- 5.4; P = 0.99). In type IIa fibers, MCarn increased in the HIIT group (from 18.8 +/- 6.1 to 20.5 +/- 6.4; P = 0.067) but not the CON group (from 19.7 +/- 4.5 to 18.8 +/- 4.4; P = 0.37). No changes in gene expression were shown. Conclusions In the absence of any dietary intake of -alanine, HIIT increased MCarn content. The contribution of increased MCarn to the total increase in m(in vitro) appears to be small.
- The Influence of Caffeine Expectancies on Simulated Soccer Performance in Recreational Individuals(2019) SHABIR, Akbar; HOOTON, Andy; SPENCER, George; STOREY, Mitch; ENSOR, Olivia; SANDFORD, Laura; TALLIS, Jason; SAUNDERS, Bryan; HIGGINS, Matthew F.Caffeine (CAF) has been reported to improve various facets associated with successful soccer play, including gross motor skill performance, endurance capacity and cognition. These benefits are primarily attributed to pharmacological mechanisms. However, evidence assessing CAF's overall effects on soccer performance are sparse with no studies accounting for CAF's potential psychological impact. Therefore, the aim of this study was to assess CAF's psychological vs. pharmacological influence on various facets of simulated soccer performance. Utilising a double-dissociation design, eight male recreational soccer players (age: 22 +/- 5 years, body mass: 78 +/- 16 kg, height: 178 +/- 6 cm) consumed CAF (3 mg/kg/body mass) or placebo (PLA) capsules, 60 min prior to performing the Loughborough Intermittent Shuttle Test (LIST) interspersed with a collection of ratings of perceived exertion (RPE), blood glucose and lactate, heart rate and performing the Loughborough Soccer Passing Test (LSPT). Whole-body dynamic reaction time (DRT) was assessed pre- and post- LIST, and endurance capacity (T-LIM) post, time-matched LIST. Statistical analysis was performed using IBM SPSS (v24) whilst subjective perceptions were explored using template analysis. Mean T-LIM was greatest (p < 0.001) for synergism (given CAF/told CAF) (672 +/- 132 s) vs. placebo (given PLA/told PLA) (533 +/- 79 s). However, when isolated, T-LIM was greater (p = 0.012) for CAF psychology (given PLA/told CAF) (623 +/- 117 s) vs. pharmacology (given CAF/told PLA) (578 +/- 99 s), potentially, via reduced RPE. Although DRT performance was greater (p = 0.024) post-ingestion (+5 hits) and post-exercise (+7 hits) for pharmacology vs. placebo, psychology and synergism appeared to improve LSPT performance vs. pharmacology. Interestingly, positive perceptions during psychology inhibited LSPT and DRT performance via potential CAF over-reliance, with the opposite occurring following negative perceptions. The benefits associated with CAF expectancies may better suit tasks that entail lesser cognitive-/skill-specific attributes but greater gross motor function and this is likely due to reduced RPE. In isolation, these effects appear greater vs. CAF pharmacology. However, an additive benefit may be observed after combining expectancy with CAF pharmacology (i.e., synergism).
article Acute effects of beta-alanine ingestion on regulatory mechanisms of muscle carnosine content: an experimental approach(2023) COSTA, Breno Duarte; CARVALHO, Arthur; LONGOBARD, Igor; SAUNDERS, BryanCarnosine is a dipeptide with several physiological actions, standing out in its intracellular buffering capacity. It is synthesized in situ from the amino acids L-histidine and beta-alanine (BA) and the increase in muscle carnosine concentration caused by BA supplementation is widely known. However, the relationship between the acute beta-alanine response, and proteins and genes related to carnosine metabolism after acute and chronic BA supplementation and its relationship to chronic changes in muscle carnosine content are not fully understood. The aim of this study was to evaluate the acute responses to BA supplementation on the plasma concentration of BA, on the expression of genes related to carnosine metabolism and on their respective content in skeletal muscle, before and after chronic BA supplementation. Fourteen healthy and physically active men (participating in weekly physical exercise, but not involved in a structured training program) aged between 18 and 45 years were recruited, they underwent acute supplementation of 1600 mg of BA before and after a chronic supplementation period of 6400 mg/day for 4 weeks. Muscle samples were collected before and after the supplementation period to assess expression and content of proteins and genes related to carnosine metabolism. The analysis of these parameters will help in the understanding of carnosine metabolism and in the determination of more individualized and efficient supplementation guidelines.- Acute effects of beetroot juice and caffeine co-ingestion during a team-sport-specific intermittent exercise test in semi-professional soccer players: a randomized, double-blind, placebo-controlled study(2022) BERJISIAN, Erfan; MCGAWLEY, Kerry; SAUNDERS, Bryan; DOMINGUEZ, Raul; KOOZEHCHIAN, Majid S.; OLIVEIRA, Caio Victor Coutinho de; RAFIEI, Ramin; MIRAFTABI, Hossein; SARSHIN, Amir; NADERI, AlirezaBackground Beetroot juice (BJ) and caffeine (CAF) are considered as ergogenic aids among athletes to enhance performance, however, the ergogenic effects of BJ and CAF co-ingestion are unclear during team-sport-specific performance. This study aimed to investigate the acute effects of BJ and CAF co-ingestion on team-sport-specific performance, compared with placebo (PL), BJ, and CAF alone. Method Sixteen semi-professional male soccer players (age: 19.8 +/- 2.2 years, body mass: 69.2 +/- 6.1 kg, height: 177.3 +/- 6.0 cm) completed four experimental trials using a randomized, double-blind study design: BJ + CAF, CAF + PL, BJ + PL, and PL + PL. Countermovement jump with arm swing (CMJAS) performance and cognitive function by Stroop Word-Color test were evaluated before and after the Yo-Yo Intermittent Recovery Test level 1 (YYIR1). Also, rate of perceived exertion (RPE), heart rate, and gastrointestinal (GI) discomfort were measured during each session. Results No significant differences were shown between test conditions for total distance covered in YYIR1 (BJ + CAF: 1858 +/- 455 m, CAF + PL: 1798 +/- 422 m, BJ + PL: 1845 +/- 408 m, PL + PL 1740 +/- 362 m; p = 0.55). Moreover, CMJAS performance, cognitive function, and RPE during the YYIR1 were not significantly different among conditions (p > 0.05). However, the average heart rate during the YYIR1 was higher in CAF + PL compared to PL + PL (by 6 +/- 9 beats/min; p < 0.05), and GI distress was greater in BJ + CAF compared to PL + PL (by 2.4 +/- 3.6 a.u.; p < 0.05). Conclusion These results suggest, neither acute co-ingestion of BJ + CAF nor BJ or CAF supplementation alone significantly affected team-sport-specific performance compared to the PL treatment.