Does creatine supplementation harm renal function?

Enquanto o consumo de creatina por atletas e praticantes de atividade física tem crescido vertiginosamente, os efeitos adversos desse suplemento continuam sendo alvos de calorosos debates científicos, sobretudo no que se refere à função renal. O objetivo dessa revisão é descrever as falhas metodológicas e lacunas na literatura, que contribuem para a divergência do tema. Relatos de caso sugerem que a creatina é um potencial agente nefrotóxico. Em contrapartida, estudos longitudinais, embora possuam diversas limitações, indicam o oposto. Pesquisas com humanos não demonstram efeitos deletérios da suplementação de creatina à função renal, porém a falta de controle experimental e o caráter retrospectivo da maioria delas comprometem as conclusões dos autores. Já os estudos experimentais com ratos empregam bons marcadores de função renal e possuem controle de variáveis satisfatório. Contudo, os resultados destes são contraditórios. Estudos futuros devem investigar os efeitos da suplementação de creatina em diversas patologias renais, assim como em idosos, diabéticos do tipo 2 e hipertensos, cuja propensão a nefropatia é bem descrita. Não há evidências de que a suplementação de creatina prejudique a função renal em sujeitos saudáveis, quando consumida na dosagem preconizada. Diante disso, questiona-se a legitimidade científica da proibição do comércio de creatina no Brasil.While creatine consumption has been greatly increasing among athletes and physical activity practitioners, the adverse effects of this supplement remain scientifically controversial, especially concerning renal function. The aim of this review is to describe the methodological limitations and gaps in the literature which contribute to the topic’s divergence. Case reports suggest that creatine is a nephrotoxic agent. On the other hand, despite having several limitations, longitudinal studies have indicated the opposite. Research with humans does not demonstrate any deleterious effects as a consequence of creatine supplementation; however, the absence of experimental control as well as their retrospective characteristics compromise the authors’ conclusion. Experimental studies with animal models though, use both gold standard for renal function and have satisfactory variable control. However, the results remain controversial. Future studies should investigate the effects of creatine supplementation in several kidneys diseases as well as in the elderly, type 2 diabetis and hypertensive individuals, whose tendency to renal dysfunction is well-described. There is not evidence that creatine supplementation causes renal deterioration in healthy subjects when it is ingested in the recommended dosage. Thus, we have some concerns about the sale prohibition of creatine supplementation in Brazil

Estratégias de reposição hídrica: revisão e recomendações aplicadas

Grande atenção tem-se dado às estratégias de reidratação durante e após a atividade física, como forma de manter os líquidos corporais. Quando discutimos a necessidade de repor as perdas hídricas associadas à atividade física, buscamos, em última análise, formas de prolongar ou manter pelo maior tempo possível o rendimento do indivíduo. Alterações das funções fisiológicas conseqüentes das perdas hídricas comprometem o desempenho, tomando-se assim fatores determinantes de fadiga. Este artigo de revisão discute a necessidade de repor as perdas hídricas associadas à atividade física, apresentando algumas * estratégias presentes na literatura. Alguns artigos consideram a reposição hídrica, em conjunto com a oferta de nutrientes e eletrólitos, como um importante recurso ergogênico, já que a depleção de substratos energéticos (glicogênio muscular e hepático), o acúmulo de metabólitos (lactato e ions H4) e o prejuízo dos processos de termorregulação estão intimamente ligados à diminuição do desempenho. Assim, além da oferta de água, as estratégias discutidas nesta revisão procuram também avaliar a disponibilidade de carboidratos e eletrólitos, quer como agentes facilitadores da própria reposição hídrica ou como fonte exógena de substratosThe fluid replacement strategies are very important before, during and after physical activity to maintain body fluids. When we discuss about the need for fluid replacement as a consequence of physical activity, the main focus is to enhance endurance to prolonged exercise. The physiological modifications due to body water loss can decrease the performance and also be responsible to the fatigue. This review paper will emphasize the importance of body water replacement due to physical activity, and present different ways to manage it. Some papers regard the water consumption, associated to different nutrients and electrolytes and an important ergogenic aid, as a mean of trying to keep carbohydrate concentration in the body (liver and muscle glycogen), as well as to prevent the accumulation of metabolites (lactate and H+ ions) and also to keep the efficiency of thermoregulatory process. Moreover, this paper will argue that the availability of carbohydrates and electrolytes will facilitate water replacement as well as being an exogen source of substrate

Possible effect of the supplementation of branched chain aminoacids, aspartate and asparagine on anaerobic threshold

Recently, the concept of "Anaerobic Threshold” has been widely criticized. The most important critiques are about the mccanisms involved in the concentration of blood lactate increment, mainly muscular hipoxia, and about the supposed aclion-and-reaction relation between the metabolic and ventilatory threshold. In spite of the criticisms the Anaerobic Threshold has been found to have wide aplicabilities, thus, many researches had been done in order to facilitate its measurement, not in a invasive way, but with ventilator)' parameters and using the heart rate deflection curve. Recently, the amount of people who practices motor activities using aminoacids has been widely spread, and this fact became an issue of discussion to many researches. It was proposed that suplemcntation with branched chain aminoacids, aspartate and asparagine results in increased resistance to prolonged exercise, due to an increase of the muscle glycogen content and oxaloacetatc synthesis to sustain the Krebs cycle activity and oxidative metabolism. Thus, glucose transport to inner muscle cell decreases, delaying the depletion of muscle glycogen content and metabolic acidosis, the evident causes of fatigue. In consequence, the oxidation of fatty acids during continuous and moderate exercise increases, delaying the lactate accumulation in muscles and blood. This would delay the metabolic stimulus for the H C 03‘ buffering process and consequent C 02 ventilator)' compensation, and may dissociate the metabolic threshold from ventilator)' threshold. This dissociation of thresholds would reinforce critiques about the concept of Anaerobic Threshold and it would, other, also, make difficult its identification through methods such as the heart rale deflection curveRecentemente o conceito “Limiar Anacróbio” tem sido muito criticado. As principais críticas repousam sobre os mecanismos considerados para o aumento da concentração de laclato sangüíneo, hipóxia muscular principalmente, c sobre a suposta relação de causa-c-cfeito entre os limiares mctabólico e ventilatório. Apesar de criticado, o conceito Limiar Anacróbio encontrou muitas aplicações, c por esta razão, vários estudos foram realizados para facilitar a sua determinação não invasivamente, a partir de parâmetros ventilatórios c da dcílexão da curva de freqüência cardíaca. Recentemente o uso de aminoácidos tem se difundido largamente entre os praticantes de atividades motoras, tornando-se objeto de estudo para vários pesquisadores. Foi proposto que a suplementação de aminoácidos de cadeia ramificada, aspartalo c asparagina promove aumento da resistência ao esforço físico prolongado, em decorrência do aumento do conteúdo de glicogênio muscular c síntese de oxaloacetato para manutenção da atividade do ciclo de Krebs c do própio metabolismo oxidativo. Com isto o transporte de glicose para o interior da célula muscular diminui, retardando a dcplcção de glicogênio muscular e a acidose metabólica, causas evidentes de fadiga. Em conseqüência, a oxidação de AGLs durante o exercício contínuo moderado aumenta, retardando o acúmulo de lactato sangüíneo c muscular. Isto retardaria o estímulo mctabólico para o processo de tamponamento pelo H C 03' c a conseqüente compensação venlilalória para C 0 2, podendo dissociar os limiares mctabólico c ventilatório. A dissociação dos limiares reforçaria as críticas sobre o conceito Limiar Anacróbio c poderia, inclusive, prejudicar a sua identificação através de outros métodos, como por exemplo, a dcílexão da curva de freqüência cardíac

Técnicas de coaching de bemestar na mudança do estilo de vida no sistema público de saúde

According to the latest Vigitel 2017 report, non-communicable chronic diseases accounted for 68% of a total of 38 million deaths worldwide in 2012. In Brazil, the scenario is no different; in 2011 the non-communicable diseases were responsible for 68.3% of all deaths. Thousands of dollars are spent today on policies that encourage healthier living habits, but this strategy, by itself, has continually failed to produce consistent and long-lasting results. A new approach is needed that promotes lifestyle changes, making it possible to improve people’s health parameters. The process of coaching supports the development of a help-oriented relationship, encouraging patients to identify their vision, needs and goals. In addition, coaching aims to assist in the organization of routines and priorities, while putting patients in control of their health end-goal.De acordo com o último relatório da Vigitel 2017 as Doenças Crônicas Não Transmissíveis (DCNT) são responsáveis por 68% de um total de 38 milhões de mortes ocorridas no mundo em 2012. No Brasil, esse cenário não é diferente: em 2011 as DCNT foram responsáveis por 68,3% do total de mortes. Milhares de dólares são gastos hoje com políticas que estimulam hábitos de vida mais saudável, mas essa estratégia, por si só, tem continuamente falhado em produzir resultados consistentes e duradouros. É necessário uma nova abordagem, que promova mudanças no estilo de vida, possibilitando a melhora dos parâmetros de saúde das pessoas. O processo de coaching apoia o desenvolvimento de um relacionamento de ajuda, incentivando o paciente a identificar sua visão, necessidades e objetivos. Além disso, o coaching visa ajudar na organização de rotinas e prioridades, enquanto coloca o paciente no controle de seu destino de saúde

Genetics and sport performance: current challenges and directions to the future

In recent years there has been a great progress in molecular biology techniques, which has facilitated the researches on influence of genetics on human performance. There are specific regions of DNA that can vary between individuals. Such variations (i.e., polymorphisms) may, in part, explain why some individuals have differentiated responses to certain stimuli, including the responses to sports training. In a particular sport, the presence of specific polymorphisms may contribute to high levels of performance. Since 1998, several polymorphisms have been associated with athletic phenotypes; however the accumulation of information generated over these 15 years shows that the influence of genetics to sport is extremely complex. In this review, we will summarise the current status of the field, discussing the implications of available knowledge for the practice of professionals involved with the sport and suggesting future directions for research. We also discuss topics related to the importance of polygenic profile characterization of athletes, methods for the identification of new polymorphisms associated with physical performance, the use of genetic testing for predicting competitive success, and how crucial is the genetic profile for the success athletes in competition.In recent years there has been a great progress in molecular biology techniques, which has facilitated the researches on influence of genetics on human performance. There are specific regions of DNA that can vary between individuals. Such variations (i.e., polymorphisms) may, in part, explain why some individuals have differentiated responses to certain stimuli, including the responses to sports training. In a particular sport, the presence of specific polymorphisms may contribute to high levels of performance. Since 1998, several polymorphisms have been associated with athletic phenotypes; however the accumulation of information generated over these 15 years shows that the influence of genetics to sport is extremely complex. In this review, we will summarise the current status of the field, discussing the implications of available knowledge for the practice of professionals involved with the sport and suggesting future directions for research. We also discuss topics related to the importance of polygenic profile characterization of athletes, methods for the identification of new polymorphisms associated with physical performance, the use of genetic testing for predicting competitive success, and how crucial is the genetic profile for the success athletes in competition

The need of a weight management control program in judo: a proposal based on the successful case of wrestling

Judo competitions are divided into weight classes. However, most athletes reduce their body weight in a few days before competition in order to obtain a competitive advantage over lighter opponents. To achieve fast weight reduction, athletes use a number of aggressive nutritional strategies so many of them place themselves at a high health-injury risk. In collegiate wrestling, a similar problem has been observed and three wrestlers died in 1997 due to rapid weight loss regimes. After these deaths, the National Collegiate Athletic Association had implemented a successful weight management program which was proven to improve weight management behavior. No similar program has ever been discussed by judo federations even though judo competitors present a comparable inappropriate pattern of weight control. In view of this, the basis for a weight control program is provided in this manuscript, as follows: competition should begin within 1 hour after weigh-in, at the latest; each athlete is allowed to be weighed-in only once; rapid weight loss as well as artificial rehydration (i.e., saline infusion) methods are prohibited during the entire competition day; athletes should pass the hydration test to get their weigh-in validated; an individual minimum competitive weight (male athletes competing at no less than 7% and females at no less than 12% of body fat) should be determined at the beginning of each season; athletes are not allowed to compete in any weight class that requires weight reductions greater than 1.5% of body weight per week. In parallel, educational programs should aim at increasing the athletes', coaches' and parents' awareness about the risks of aggressive nutritional strategies as well as healthier ways to properly manage body weight.The authors would like to thank FAPESP (#06/51293-4 and #09/02896-6) and CNPq (#1428 10/2009-6) for the financial support.The authors would like to thank FAPESP (#06/512934 and #09/028966) and CNPq (#1428 10/20096) for the financial support

Recovery time between weigh-in and first match in State level judo competitions

Rapid weight loss is highly prevalent among combat sport athletes. After the weigh-in, there is a period in which athletes can refeed and rehydrate before the combats. The length of this recovery period is determinant for performance in the subsequent combats. No study, however, has determined the time patterns of such period. The purpose of this study was to determine the patterns of recovery time between the weigh-in and the first combats during judo competitions. One hundred and seventeen juvenile, junior and senior male athletes were analyzed during two São Paulo state competitions. The time at which each athlete has finished the weight-in and the time at which they have started the first combat were recorded and then the recovery period between weigh-in and combats was calculated. Average recovery time was approximately four hours. Most athletes had a 2.5 to 5-hour recovery time between the weigh-in and the first combat. Senior athletes had a significant longer recovery time compared to junior and juvenile (p < 0.001). Junior athletes also had a significant longer recovery time in comparison to juvenile athletes (p < 0.001). In conclusion, the patterns for recovery time presented in this study are likely to be a standard if competitions of similar size and organization are considered. Recovery period for the majority of athletes is enough to allow them to refeed and rehydrate, so the impact of weight loss on performance would be minimal. This can stimulate athletes to engage in potentially harmful rapid weight loss procedures.A perda rápida de peso é altamente prevalente entre atletas de luta. No judô, há um período entre a pesagem e o início da competição no qual atletas podem se recuperar da perda de peso. Apesar desse tempo ser determinante para o desempenho, nenhum estudo avaliou seu padrão de duração. Este estudo objetivou determinar o padrão de duração do tempo entre a pesagem e o início das lutas em competições oficiais de judô. Foram analisados 117 atletas do sexo masculino (classes juvenil, júnior e sênior) durante duas competições oficiais. Registraram-se o horário de término da pesagem e do início da primeira luta de cada atleta. O tempo médio de recuperação foi de aproximadamente quatro horas. A maior parte dos atletas teve aproximadamente 2,5 - 5 horas entre a pesagem e o início das lutas. O período para a classe sênior foi significantemente maior do que o das classes júnior e juvenil (p < 0,01) e o da classe júnior foi significantemente maior do que o da classe juvenil (p < 0,01). Conclui-se que os tempos de recuperação aqui registrados são provavelmente padrões para competições de mesmo porte e esquema organizacional, embora os tempos específicos para as classes etárias possam se modificar. O período que a maioria dos atletas teve para recuperar-se é suficiente para adequada ingestão de alimentos e líquidos, o que minimiza o impacto da perda de peso sobre o desempenho e estimula a pratica de métodos agressivos de perda rápida de peso

Does long-term creatine supplementation impair kidney function in resistance-trained individuals consuming a high-protein diet?

Abstract\ud \ud \ud \ud Background\ud \ud The aim of this study was to determine the effects of creatine supplementation on kidney function in resistance-trained individuals ingesting a high-protein diet.\ud \ud \ud \ud Methods\ud \ud A randomized, double-blind, placebo-controlled trial was performed. The participants were randomly allocated to receive either creatine (20 g/d for 5 d followed by 5 g/d throughout the trial) or placebo for 12 weeks. All of the participants were engaged in resistance training and consumed a high-protein diet (i.e., ≥ 1.2 g/Kg/d). Subjects were assessed at baseline (Pre) and after 12 weeks (Post). Glomerular filtration rate was measured by 51Cr-EDTA clearance. Additionally, blood samples and a 24-h urine collection were obtained for other kidney function assessments.\ud \ud \ud \ud Results\ud \ud No significant differences were observed for 51Cr-EDTA clearance throughout the trial (Creatine: Pre 101.42 ± 13.11, Post 108.78 ± 14.41 mL/min/1.73m2; Placebo: Pre 103.29 ± 17.64, Post 106.68 ± 16.05 mL/min/1.73m2; group x time interaction: F = 0.21, p = 0.64). Creatinine clearance, serum and urinary urea, electrolytes, proteinuria, and albuminuria remained virtually unchanged.\ud \ud \ud \ud Conclusions\ud \ud A 12-week creatine supplementation protocol did not affect kidney function in resistance-trained healthy individuals consuming a high-protein diet; thus reinforcing the safety of this dietary supplement.\ud \ud \ud \ud Trial registration\ud \ud ClinicalTrials.gov NCT01817673We are thankful to Fundação de Amparo à Pesquisa do Estado de São Paulo e Conselho Nacional de Desenvolvimento Científico e Tecnológico for the financial support

Does creatine supplementation improve the plasma lipid profile in healthy male subjects undergoing aerobic training?

Abstract\ud \ud \ud \ud \ud \ud We aimed to investigate the effects of creatine (Cr) supplementation on the plasma lipid profile in sedentary male subjects undergoing aerobic training.\ud \ud \ud \ud Methods\ud \ud Subjects (n = 22) were randomly divided into two groups and were allocated to receive treatment with either creatine monohydrate (CR) (~20 g·day-1 for one week followed by ~10 g·day-1 for a further eleven weeks) or placebo (PL) (dextrose) in a double blind fashion. All subjects undertook moderate intensity aerobic training during three 40-minute sessions per week, over 3 months. High-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), very low-density lipoprotein cholesterol (VLDL), total cholesterol (TC), triglyceride (TAG), fasting insulin and fasting glycemia were analyzed in plasma. Thereafter, the homeostasis model assessment (HOMA) was calculated. Tests were performed at baseline (Pre) and after four (Post 4), eight (Post 8) and twelve (Post 12) weeks.\ud \ud \ud \ud Results\ud \ud We observed main time effects in both groups for HDL (Post 4 versus Post 8; P = 0.01), TAG and VLDL (Pre versus Post 4 and Post 8; P = 0.02 and P = 0.01, respectively). However, no between group differences were noted in HDL, LDL, CT, VLDL and TAG. Additionally, fasting insulin, fasting glycemia and HOMA did not change significantly.\ud \ud \ud \ud Conclusion\ud \ud These findings suggest that Cr supplementation does not exert any additional effect on the improvement in the plasma lipid profile than aerobic training alone.We are grateful to Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, 2003/140885) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for financial support.We are grateful to Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, 2003/14088-5) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for financial support

Association between physical activity level of leisure and cognitive performance in healthy children

O objetivo do presente estudo foi avaliar a associação da atividade física de lazer sobre o desempenho cognitivo em crianças saudáveis. Foi conduzido um estudo transversal, no qual 100 crianças (10,8 ± 0,6 anos) foram divididas em dois grupos: "Insuficientemente Ativos" (IA) e "Ativos" (A). O desempenho cognitivo foi avaliado pelo Teste de Memória e Aprendizagem de Figuras, o Teste de Stroop e o Teste de Trilhas. Foi observada uma diferença estatisticamente significante entre os grupos para a condição de memória incidental do Teste de Memória e Aprendizagem de Figuras (IA: 6,6 ± 1,37 versus A: 7,1 ± 1,24; p = 0,03). Entretanto, não foram observadas diferenças estatisticamente significativas entre os grupos para todas as outras variáveis. Esses achados revelam uma influência positiva da atividade física de lazer sobre a memória incidental de crianças saudáveis, mas não a memória tardia, a flexibilidade mental e o controle inibitório. Estudos com maiores amostras e medidas diretas de avaliação de nível de atividade física precisam ser conduzidos para confirmar esses achados.The aim of this study was to assess the association of leisure physical activity on cognitive performance in healthy children. It was performed a cross-sectional study in which 100 children (10.8 ± 0.6 years of age) were divided into two groups as follows: "Insufficiently actives" (IA) and "Actives" (A). The cognitive performance was assessed by Memory and Learning of Figure Test, Stroop Test, Trail Making Test. It was observed a significant difference between groups for an incidental memory task from Memory and Learning of Figure Test (IA: 6.6 ± 1.4 versus A: 7.1 ± 1.2; p = 0.03). However, no significant differences were noted for any other variables. These findings reveal a positive influence of leisure physical activity on the incidental memory, but not long-term memory, mental flexibility, and inhibitory control in healthy children. Future studies with larger samples and direct measures of physical activity levels must be conducted to confirm these results