Práticas alimentares, efeito do índice glicêmico e da hidratação no desempenho de ciclistas
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2010-12-10
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Universidade Federal de Viçosa
Resumo
Esta dissertação é composta por três estudos. Primeiro estudo: teve como
objetivo revisar os efeitos da ingestão pré-exercício de refeições de alto, moderado e baixo índice glicêmico (IG) no desempenho. Foi realizada uma busca na base de
dados Medline, Scielo, Science Direct e Pubmed. Alguns estudos evidenciaram
associação positiva entre a ingestão de refeição de BIG ou moderado índice
glicêmico (MOD-IG) antes do exercício e a melhoria no desempenho físico, outros
não observaram diferenças significantes na distância, no trabalho ou no tempo do
teste de desempenho realizado após o consumo de refeições diferindo em IG. Torna-se necessária à realização de mais pesquisas bem controladas para avaliar o efeito do IG no desempenho. Segundo estudo: o objetivo foi investigar os hábitos alimentares do café da manhã pré-exercício e as estratégias nutricionais usadas antes e durante o treinamento e competição de ciclistas de mountain bike. Foram entrevistados 146 ciclistas participantes de uma competição nacional de ciclismo. O questionário incluía 13 questões sobre as características dos participantes, hábitos alimentares pré-exercício e os sintomas sistêmicos ou gastrintestinais apresentados durante o treinamento e competição. Todos participantes consumiam café da manhã pré-competição. Os alimentos como banana, pão branco e pão integral foram os mais consumidos no café da manhã pré-treino e pré-competição. Em relação ao uso de suplementos, 42 % e 58 % dos participantes faziam uso no café da manhã antes do treinamento e competição, respectivamente. A maioria dos participantes indicou o consumo de algum suplemento durante o treino (88,35 %) e competição (97,26 %). Do total de participantes, 86,3 % relataram algum sintoma adverso durante o exercício. Apesar da maioria dos participantes ter o hábito de ingerir café da manhã pré-exercício, grande parte dos alimentos selecionados foi inadequada. Eles também apresentaram alto consumo de suplementos antes e durante o exercício. Terceiro estudo: o objetivo foi comparar o efeito do IG da refeição consumida 30 minutos antes do exercício nos parâmetros metabólicos e desempenho de ciclistas com diferentes formas de hidratação (água ou isotônico) durante o exercício em cicloergômetro. Doze ciclistas consumiam uma refeição de alto índice glicêmico (AIG) ou de baixo índice glicêmico (BIG), 30 minutos antes de iniciarem um exercício em cicloergômetro durante 90 minutos, seguido por ciclo de desempenho (6 km). Durante cada etapa, foi oferecida água ou isotônico. A resposta glicêmica pós-prandial e as áreas abaixo das curvas (AAC) glicêmicas após 30 minutos do consumo das refeições de AIG foram maiores do que após a ingestão das refeições de BIG. Durante o exercício, constatou-se que a resposta glicêmica no teste de BIG e hidratação com água (BIGHA) foi mais estável em comparação ao teste de AIG e hidratação com água (AIGHA). No entanto, quando o isotônico foi consumido durante o exercício, verificou-se redução das diferenças nas respostas glicêmicas observadas após a ingestão das refeições de BIG e AIG antes do exercício. Não foi verificada diferença significante no desempenho entre os testes. O IG das refeições não afetou o desempenho de ciclistas com diferentes formas de hidratação durante a atividade física.
This dissertation is composed of three studies. First study: the objective was to review the effects of pre-exercise ingestion of high, moderate and low glycemic index (GI) meals on performance. For the first study, was held search in the Medline, Scielo, Science Direct and Pubmed databases. Some studies reveals a positive association between pre-exercise intake of LGI or MOD-GI meal and improvement in physical performance, others observed no significant differences in the distance, at work or at the time of performance testing conducted after consumption of meals differing in GI. Well-controlled studies are required to evaluated the effect of the GI on performance. Second study: the objective was to investigate the breakfast dietary habits and nutritional strategies used before and during training and competition, in mountain bikers. Were interviewed 146 cyclists of the national cyclism competition. The questionnaire included 13 questions about the participant s characteristics, pre-exercise eating habits and the systemic or gastrointestinal symptoms during training and competition. All participants consumed pre-competition breakfast. The foods banana, white bread and wholemeal bread were the most consumed for pre-training and pre-competition breakfast. Regarding the use of supplement, 42 % and 58 % of the participants used in the breakfast before of the training and competition, respectively. Most participants indicated the consumption of some supplement during training (88.35 %) and competition (97.26 %). Eighty-six percent (86.3 %) of the participants reported some adverse symptom during the exercise. Although most of the participants ingested pre-exercise breakfast, the majority of selected foods were inadequate. They also showed high supplement consumption before and during the exercise. Third study: the objective was to compare the effect of the GI of meal consumed 30 minutes prior to exercise on metabolic parameters and performance of cyclists with types different hydration (water or isotonic) during exercise on a cycle ergometer. Twelve cyclists consumed a high glycemic index (HGI) or low glycemic index (LGI) meal, 30 minutes before exercise on a cycle ergometer during 90 minutes, followed by performance cycle (6 km). During each trial, was offered water or isotonic. The postprandial glycemic response and areas under the curve (AUC) blood glucose after 30 minutes of the consuming of HGI meals were higher than after ingestion of LGI meals. During exercise, we found that glycemic response in LGI trial and hydration with water (LGIHW) was more stable than in HGI trial and hydration with water (HGIHW). However, when the isotonic was consumed during exercise, there were reduced of the differences in glycemic responses observed after the ingestion of LGI and HGI meals before exercise. There was no significant difference on performance among the trials. The GI of meals did not affect the performance of cyclists with hydration types different during the physical activity.
This dissertation is composed of three studies. First study: the objective was to review the effects of pre-exercise ingestion of high, moderate and low glycemic index (GI) meals on performance. For the first study, was held search in the Medline, Scielo, Science Direct and Pubmed databases. Some studies reveals a positive association between pre-exercise intake of LGI or MOD-GI meal and improvement in physical performance, others observed no significant differences in the distance, at work or at the time of performance testing conducted after consumption of meals differing in GI. Well-controlled studies are required to evaluated the effect of the GI on performance. Second study: the objective was to investigate the breakfast dietary habits and nutritional strategies used before and during training and competition, in mountain bikers. Were interviewed 146 cyclists of the national cyclism competition. The questionnaire included 13 questions about the participant s characteristics, pre-exercise eating habits and the systemic or gastrointestinal symptoms during training and competition. All participants consumed pre-competition breakfast. The foods banana, white bread and wholemeal bread were the most consumed for pre-training and pre-competition breakfast. Regarding the use of supplement, 42 % and 58 % of the participants used in the breakfast before of the training and competition, respectively. Most participants indicated the consumption of some supplement during training (88.35 %) and competition (97.26 %). Eighty-six percent (86.3 %) of the participants reported some adverse symptom during the exercise. Although most of the participants ingested pre-exercise breakfast, the majority of selected foods were inadequate. They also showed high supplement consumption before and during the exercise. Third study: the objective was to compare the effect of the GI of meal consumed 30 minutes prior to exercise on metabolic parameters and performance of cyclists with types different hydration (water or isotonic) during exercise on a cycle ergometer. Twelve cyclists consumed a high glycemic index (HGI) or low glycemic index (LGI) meal, 30 minutes before exercise on a cycle ergometer during 90 minutes, followed by performance cycle (6 km). During each trial, was offered water or isotonic. The postprandial glycemic response and areas under the curve (AUC) blood glucose after 30 minutes of the consuming of HGI meals were higher than after ingestion of LGI meals. During exercise, we found that glycemic response in LGI trial and hydration with water (LGIHW) was more stable than in HGI trial and hydration with water (HGIHW). However, when the isotonic was consumed during exercise, there were reduced of the differences in glycemic responses observed after the ingestion of LGI and HGI meals before exercise. There was no significant difference on performance among the trials. The GI of meals did not affect the performance of cyclists with hydration types different during the physical activity.
Descrição
Palavras-chave
Índice glicêmico, Refeição pré-exercício, Desempenho, Nutrição esportiva, Mountain bike, Hidratação, Água isotônico, Glycemic índex, Pré-exercise meal, performance, Sports nutrition, Mountain bike, Hydration, Isotonic water
Citação
CAZAL, Mariana de Melo. Dietary practices, effect of the glycemic índex and hydration on performance of cyclists. 2010. 128 f. Dissertação (Mestrado em Valor nutricional de alimentos e de dietas; Nutrição nas enfermidades agudas e crônicas não transmis) - Universidade Federal de Viçosa, Viçosa, 2010.