BRYAN SAUNDERS
Projetos de Pesquisa
Unidades Organizacionais
LIM/17 - Laboratório de Investigação em Reumatologia, Hospital das Clínicas, Faculdade de Medicina
11 resultados
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bookPart 3 Citação(ões) na Scopus Creatine supplementation in sport, exercise and health(2019) RAWSON, E. S.; DOLAN, E.; SAUNDERS, B.; WILLIAMS, M. E.; GUALANO, B.- A Systematic Risk Assessment and Meta-Analysis on the Use of Oral beta-Alanine Supplementation(2019) DOLAN, Eimear; SWINTON, Paul A.; PAINELLI, Vitor de Salles; HEMINGWAY, Benedict Stephens; MAZZOLANI, Bruna; SMAIRA, Fabiana Infante; SAUNDERS, Bryan; ARTIOLI, Guilherme G.; GUALANO, Brunobeta-Alanine supplementation is one of the world's most commonly used sports supplements, and its use as a nutritional strategy in other populations is ever-increasing, due to evidence of pleiotropic ergogenic and therapeutic benefits. Despite its widespread use, there is only limited understanding of potential adverse effects. To address this, a systematic risk assessment and meta-analysis was undertaken. Four databases were searched using keywords and Medical Subject Headings. All human and animal studies that investigated an isolated, oral, beta-alanine supplementation strategy were included. Data were extracted according to 5 main outcomes, including 1) side effects reported during longitudinal trials, 2) side effects reported during acute trials, 3) effect of supplementation on circulating health-related biomarkers, 4) effect of supplementation on skeletal muscle taurine and histidine concentration, and 5) outcomes from animal trials. Quality of evidence for outcomes was ascertained using the Grading of Recommendations Assessment Development and Evaluation (GRADE) framework, and all quantitative data were meta-analyzed using multilevel models grounded in Bayesian principles. In total, 101 human and 50 animal studies were included. Paraesthesia was the only reported side effect and had an estimated OR of 8.9 [95% credible interval (CrI): 2.2, 32.6] with supplementation relative to placebo. Participants in active treatment groups experienced similar dropout rates to those receiving the placebo treatment. beta-Alanine supplementation caused a small increase in circulating alanine aminotransferase concentration (effect size, ES: 0.274, CrI: 0.04, 0.527), although mean data remained well within clinical reference ranges. Meta-analysis of human data showed no main effect of beta-alanine supplementation on skeletal muscle taurine (ES: 0.156; 95% CrI: -0.38, 0.72) or histidine (ES: -0.15; 95% CrI: -0.64, 0.33) concentration. A main effect of beta-alanine supplementation on taurine concentration was reported for murine models, but only when the daily dose was >= 3% beta-alanine in drinking water. The results of this review indicate that beta-alanine supplementation within the doses used in the available research designs, does not adversely affect those consuming it.
- Effects of -alanine and sodium bicarbonate supplementation on the estimated energy system contribution during high-intensity intermittent exercise(2019) SILVA, Rafael Pires da; OLIVEIRA, Luana Farias de; SAUNDERS, Bryan; KRATZ, Caroline de Andrade; PAINELLI, Vitor de Salles; SILVA, Vinicius da Eira; MARINS, Joao Carlos Bouzas; FRANCHINI, Emerson; GUALANO, Bruno; ARTIOLI, Guilherme GianniniThe effects of -alanine (BA) and sodium bicarbonate (SB) on energy metabolism during work-matched high-intensity exercise and cycling time-trial performance were examined in 71 male cyclists. They were randomised to receive BA+placebo (BA, n=18), placebo+SB (SB, n=17), BA+SB (BASB, n=19), or placebo+placebo (PLA, n=18). BA was supplemented for 28days (6.4gday(-1)) and SB (0.3gkg(-1)) ingested 60min before exercise on the post-supplementation trial. Dextrose and calcium carbonate were placebos for BA and SB, respectively. Before (PRE) and after (POST) supplementation, participants performed a high-intensity intermittent cycling test (HICT-110%) consisting of four 60-s bouts at 110% of their maximal power output (60-s rest between bouts). The estimated contribution of the energy systems was calculated for each bout in 39 of the participants (BA: n=9; SB: n=10; BASB: n=10, PLA: n=10). Ten minutes after HICT-110%, cycling performance was determined in a 30-kJ time-trial test in all participants. Both groups receiving SB increased estimated glycolytic contribution in the overall HICT-110%, which approached significance (SB: +23%, p=0.068 vs. PRE; BASB: +18%, p=0.059 vs. PRE). No effects of supplementation were observed for the estimated oxidative and ATP-PCr systems. Time to complete 30 kJ was not significantly changed by any of the treatments, although a trend toward significance was shown in the BASB group (p=0.06). We conclude that SB, but not BA, increases the estimated glycolytic contribution to high-intensity intermittent exercise when total work done is controlled and that BA and SB, either alone or in combination, do not improve short-duration cycling time-trial performance.
- Editorial: Personalized Sport and Exercise Nutrition(2019) SAUNDERS, Bryan; EL-SOHEMY, Ahmed; DERAVE, Wim
bookPart 0 Citação(ões) na Scopus Beta-alanine supplementation in sport, exercise and health(2019) SAUNDERS, B.; DOLAN, E.- Comparative physiology investigations support a role for histidine-containing dipeptides in intracellular acid base regulation of skeletal muscle(2019) DOLAN, Eimear; SAUNDERS, Bryan; HARRIS, Roger Charles; BICUDO, Jose Eduardo Pereira Wilken; BISHOP, David John; SALE, Craig; GUALANO, BrunoHistidine containing dipeptides (HCDs: carnosine, anserine and balenine) have numerous therapeutic and ergogenic properties, but there is a lack of consensus on the mechanistic pathways through which they function. Potential roles include intracellular buffering, neutralisation of reactive species, and calcium regulation. Comparative investigations of the HCD content of various species provide unique insight into their most likely mechanisms of action. This review chronologically describes how the comparative physiology studies, conducted since the beginning of the 20th century, have shaped our understanding of the physiological roles of HCDs. The investigation of a wide range of physiologically distinct species indicates that those species with a strong reliance on non-oxidative forms of energy production are abundant in HCDs. These include: whales who experience long periods of hypoxia while diving; racehorses and greyhound dogs who have highly developed sprint abilities, and chickens and turkeys whose limited capacity for flight is largely fuelled by their white, glycolytic, muscle. Additionally, a higher HCD content in the Type 2 muscle fibres of various species (which have greater capacity for non-oxidative metabolism) was consistently observed. The pKa of the HCDs render them ideally suited to act as intracellular physicochemical buffers within the pH transit range of the skeletal muscle. As such, their abundance in species which show a greater reliance on non-oxidative forms of energy metabolism, and which experience regular challenges to acid-base homeostasis, provides strong evidence that intracellular proton buffering is an important function of the HCDs in skeletal muscle.
- Effect of beta-alanine supplementation during high-intensity interval training on repeated sprint ability performance and neuromuscular fatigue(2019) MILIONI, Fabio; POLI, Rodrigo Araujo Bonetti de; SAUNDERS, Bryan; GUALANO, Bruno; ROCHA, Alisson L. da; SILVA, Adelino Sanchez Ramos da; MULLER, Paulo de Tarso Guerrero; ZAGATTO, Alessandro MouraThe study investigated the influence of beta-alanine supplementation during a high-intensity interval training (HIIT) program on repeated sprint ability (RSA) performance. This study was randomized, double-blinded, and placebo controlled. Eighteen men performed an incremental running test until exhaustion (T-INC) at baseline and followed by 4-wk HIIT (10 x 1min runs 90% maximal T-INC velocity [1-min recovery]). Then, participants were randomized into two groups and performed a 6-wk HIIT associated with supplementation of 6.4 g/day of beta-alanine (G beta) or dextrose (placebo group; GP). Pre- and post-6-wk HIIT + supplementation, participants performed the following tests: 1) T-INC; 2) supramaximal running test; and 3) 2 x 6 x 35-m sprints (RSA). Before and immediately after RSA, neuromuscular function was assessed by vertical jumps, maximal isometric voluntary contractions of knee extension, and neuromuscular electrical stimulations. Muscle biopsies were performed to determine muscle carnosine content, muscle buffering capacity in vitro (beta m(in) (vitro)), and content of phos-phofructokinase (PFK), monocarboxylate transporter 4 (MCT4), and hypoxia-inducible factor-1 alpha (HIF-1 alpha). Both groups showed a significant time effect for maximal oxygen uptake (G beta: 6.2 +/- 3.6% and GP: 6.5 +/- 4.2%; P > 0.01); only G beta showed a time effect for total (-3.0 +/- 2.0%; P > 0.001) and best (-3.3 +/- 3.0%; P = 0.03) RSA times. A group-by-time interaction was shown after HIIT + Supplementation for muscle carnosine (G beta: 34.4 +/- 2.3 mmol.kg(-1).dm(-1) and GP: 20.7 +/- 3.0 mmol.kg(-1) dm(-1); P = 0.003) and neuromuscular voluntary activation after RSA (G beta: 87.2 +/- 3.3% and GP: 78.9 +/- 12.4%; P = 0.02). No time effect or group-by-time interaction was shown for supramaximal running test performance, beta m, and content of PFK, MCT4, and HIF-1 alpha. In summary, beta-alanine supplementation during HIIT increased muscle carnosine and attenuated neuromuscular fatigue, which may contribute to an enhancement of RSA performance. NEW & NOTEWORTHY beta-Alanine supplementation during a high-intensity interval training program increased repeated sprint performance. The improvement of muscle carnosine content induced by beta-alanine supplementation may have contributed to an attenuation of central fatigue during repeated sprint. Overall, beta-alanine supplementation may be a useful dietary intervention to prevent fatigue.
- Can the Skeletal Muscle Carnosine Response to Beta-Alanine Supplementation Be Optimized?(2019) PERIM, Pedro; MARTICORENA, Felipe Miguel; RIBEIRO, Felipe; BARRETO, Gabriel; GOBBI, Nathan; KERKSICK, Chad; DOLAN, Eimear; SAUNDERS, BryanCarnosine is an abundant histidine-containing dipeptide in human skeletal muscle and formed by beta-alanine and L-histidine. It performs various physiological roles during exercise and has attracted strong interest in recent years with numerous investigations focused on increasing its intramuscular content to optimize its potential ergogenic benefits. Oral beta-alanine ingestion increases muscle carnosine content although large variation in response to supplementation exists and the amount of ingested beta-alanine converted into muscle carnosine appears to be low. Understanding of carnosine and beta-alanine metabolism and the factors that influence muscle carnosine synthesis with supplementation may provide insight into how beta-alanine supplementation may be optimized. Herein we discuss modifiable factors that may further enhance the increase of muscle carnosine in response to beta-alanine supplementation including, (i) dose; (ii) duration; (iii) beta-alanine formulation; (iv) dietary influences; (v) exercise; and (vi) co-supplementation with other substances. The aim of this narrative review is to outline the processes involved in muscle carnosine metabolism, discuss theoretical and mechanistic modifiable factors which may optimize the muscle carnosine response to beta-alanine supplementation and to make recommendations to guide future research.
- 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).
- Beta-alanine supplementation improves isometric, but not isotonic or isokinetic strength endurance in recreationally strength-trained young men(2019) BASSINELLO, Diogo; PAINELLI, Vitor de Salles; DOLAN, Eimear; LIXANDRAO, Manoel; CAJUEIRO, Monique; CAPITANI, Mariana de; SAUNDERS, Bryan; SALE, Craig; ARTIOLI, Guilherme G.; GUALANO, Bruno; ROSCHEL, Hamiltonbeta-Alanine (BA) supplementation may be ergogenic during high-intensity exercise, primarily due to the buffering of hydrogen cations, although the effects of beta-alanine supplementation on strength endurance are equivocal. The aim of the study was to determine the effects of 4weeks of beta-alanine supplementation on skeletal muscle endurance using a battery of performance tests. This study employed a parallel group, repeated measures, randomised, double-blinded and placebo-controlled design. Twenty recreationally strength-trained healthy males completed tests of isotonic strength endurance (repeated bench and leg press), along with tests of isometric and isokinetic endurance conducted using an isokinetic dynamometer. Tests were performed before and after a 4week intervention, comprising an intake of 6.4gday(-1) of BA (n=9) or placebo (maltodextrin, n=11). Time-to-exhaustion during the isometric endurance test improved by 17% in the BA group (p<0.01), while PL remained unchanged. No significant within-group differences (p>0.1) were shown for any of the performance variables in the isokinetic test (peak torque, fatigue index, total work) nor for the total number of repetitions performed in the isotonic endurance tests (leg or bench press). Four weeks of BA supplementation (6.4gday(-1)) improved isometric, but not isokinetic or isotonic endurance performance.