Ramadan fasting and sports performance: A Malaysian perspective

The purpose of this study was to identify factors that would affect Muslim athletes in their training or competition during the Ramadan fast. This would lead to a better understanding of the changes in lifestyle, behavioural and training practices of Muslim athletes when they participate in Ramadan fasting and exercise at the same time. A total of 172 Malaysian Muslim national elite athletes participated in a questionnaire survey assessing personal perception on sport performance, sleep pattern, food and fluid intake during Ramadan fasting. The results showed that a quarter of these athletes perceived that there was an adverse effect from the Ramadan fast on their sport performance. A majority of them (58.1%) said that Ramadan fasting did not affect their sleep pattern but 52.3% of them did take an extra nap during the daytime. Most of the athletes (45.9%) ate the same amount of calories as they normally would however 86.0 % believed that they drank more fluids than usual. The changes in lifestyle during the Ramadan fast did not adversely affect the perceived sport performance in this cohort of Muslim elite athletes. However, there is an equivocal opinion on the impact of Ramadan fasting on the quality of training

Effects of short-term intermittent fasting on neuromuscular performance, aerobic and anaerobic capacity

This dissertation aimed at providing a comprehensive approach to the effects of intermittent fasting (IF) on physical parameters, namely on performance, and body composition of young, physically active healthy males. Specifically, it comprises a set of 5 studies that were designed to i) determine the effects of IF on specific exercise performance outcomes; ii) determine the effects of different types of IF on body composition and nutritional status, exercise and control of energy intake as moderators of the impact of IF on body composition; iii) examine the effects of time-restricted feeding (TRE) on exercise performance, namely on neuromuscular strength, aerobic and anaerobic capacity as well as on body composition. Studies I and II reflect the state of the art on the effects of different types of IF (Ramadan vs. non- Ramadan) on exercise performance and body composition, showing that TRE may be effective for improving aerobic power. These studies also show that, overall, fat mass (FM) loss is more pronounced with non-Ramadan IF. In addition, we found that non-Ramadan IF leads to greater reductions in body mass index when combined with exercise training. Finally, we observed that this type of IF may be well-suited for eliciting small, but significant increases in fat-free mass (FFM), under circumstances involving control of energy intake. Study III aimed at providing an in-depth understanding of the effects of both short- and long-term TRE vs. regular diet on Wingate performance and body composition in well-trained young men. The results of this study showed that TRE, when used in combination with regular training, leads to improved supramaximal exercise performance. Subsequently, study IV unravelled that four-weeks of TRE, when used in combination with endurance running, elicits body mass reductions in trained males. Yet, when compared to that seen after following a regular dietary pattern, TRE does not offer any benefit for improving submaximal or peak exercise capacity in well-trained males. Finally, study V confirmed that TRE, when used in combination with resistance training, is effective for reducing FM and for improving high-speed strength in response to upper-body dynamic tasks (in trained males). However, once again, we determined that, when compared to that seen following a regular dietary pattern, TRE does not offer any benefit for improving lower-body strength.Esta dissertação teve o objetivo estudar os efeitos do jejum intermitente ao nível de parâmetros físicos, nomeadamente de desempenho e composição corporal em participantes jovens do sexo masculino, fisicamente ativos e saudáveis. Especificamente, este documento compreende um conjunto de 5 estudos que foram estruturados para i) determinar os efeitos do jejum intermitente sobre o desempenho de exercícios específicos; ii) determinar os efeitos de diferentes tipos de jejum intermitente sobre a composição corporal e estado nutricional, exercício e controlo de aporte energético como moderadores do impacto do jejum intermitente sobre a composição corporal; iii) examinar os efeitos da dieta com restrição de aporte energético no domínio do tempo sobre o desempenho físico, nomeadamente na força neuromuscular, capacidade aeróbia e anaeróbia e na composição corporal. Os estudos I e II refletem o estado da arte a respeito dos efeitos dos diferentes tipos de jejum intermitente (Ramadão vs. não Ramadão) no desempenho físico e na composição corporal. Em conjunto, demonstram que a dieta com restrição temporal (TRE) pode ser eficaz para melhorar a potência aeróbia. Não obstante, verificou-se que a perda de massa gorda é mais pronunciada com jejum intermitente não Ramadão. Segundo os nossos resultados, este exacerba a redução do índice de massa corporal quando combinado com treino físico. Finalmente, verificou-se que esta tipologia de jejum intermitente pode ser adequada para a indução de ligeiros aumentos (mas significativos) na massa isenta de gordura em circunstâncias que impliquem o controlo paralelo do aporte energético. O Estudo III objetivou uma compreensão mais aprofundada sobre os efeitos da TRE de curto e longo prazo vs. dieta regular ao nível do desempenho supramaximal (teste de Wingate) e da composição corporal em homens jovens bem treinados. Segundo os dados deste estudo, pode concluir-se que a o efeito combinado da TRE com o treino físico regular exacerba o desempenho físico na resposta ao exercício supramáximo. Subsequentemente, o estudo IV permitiu verificar que quatro semanas de TRE combinada com treino regular de corrida é eficaz para a redução da massa corporal em indivíduos treinados do sexo masculino. Não obstante, face aos resultados obtidos no decurso da intervenção centrada na dieta regular, a TRE não resultou em benefícios adicionais ao nível da capacidade submáxima ou de pico na corrida. Finalmente, o estudo V permitiu demonstrar que a TRE pode ser usada conjuntamente com o treino de resistência muscular para induzir uma redução de massa gorda e para melhorar o desempenho na resposta a tarefas dinâmicas realizadas com explosividade no trem superior, em homens treinados. Contudo, comparativamente aos resultados obtidos na resposta a uma dieta regular, a TRE demonstrou não oferecer qualquer benefício adicional face à melhoria da força muscular dinâmica do trem inferior

The effects of fasting for a single day and during Ramadan upon performance

Ramadan requires individuals to abstain from food and fluid intake between sunrise and sunset; physiological considerations predict that poorer mood, physical performance and mental performance will result. In addition, any difficulties will be worsened because preparations for fasting and recovery from it often mean that nocturnal sleep is decreased in length, and this independently affects mood and performance. Previous field studies have indicated that some of these predictions are borne out in practice; in the first study of the present thesis, a field study performed in Libya, these predictions were tested further by adding more physiological measurements and tests of performance. Findings indicated that Ramadan was associated with negative effects upon a wide range of variables, including rising urine daytime osmolality (indicative of progressive dehydration), subjective estimates of amounts of activities actually performed and those wished to be done (indicating less activity in the daytime), and metabolic and subjective responses to a short bout of exercise (increased effort required and metabolism tending towards fat rather than glucose catabolism). Because of the difficulties of performing a battery of tasks in a field study, two laboratory-based experiments were then performed, the second differing from the first in studying a greater range of variables and more time-points during the daytime. These two studies also differed from the situation in Ramadan in that non-Muslim students were volunteers and fasting was performed for only one day. Many of the changes previously found in Ramadan were duplicated in this work, so justifying the use of laboratory experiments lasting one day and using non-Muslim subjects as a model for some of the problems present in Ramadan. However, it was also found that preparations before the fast were often less marked than was the case with Muslims in Ramadan, a difference that can be attributed to subjects' lack of experience of fasting as well as the amount of time spent fasting. A difficulty of interpretation in all these studies was that changes could be due to fasting and/or the length of sleep, which tends to decrease. These two factors were separated in the final experiment, an intervention study performed in the laboratory. This study compared effects of different durations of fasting (4, 8 or 16 h) upon a wide variety of measures (including subjective and objective assessments of performance, dehydration and responses to a short bout of exercise) - but with an unchanged amount of nocturnal sleep and daytime naps not allowed. Many of the negative effects observed in previous studies were present in this experiment also. These findings indicate that fasting was responsible for much of the change previously observed, though some effect of sleep loss, particularly if occurring on successive days (as would occur in Ramadan) cannot be excluded. One finding common to all studies was that tests of performance that had shown variations due to the combination of circadian influences, time awake and sleep loss in other experiments (including grip strength, the Stroop test and accuracy at throwing darts) seemed little affected. Possible reasons for these negative findings are discussed, together with further experiments to separate out effects of sleep loss and fasting, and the role of subjects' experience in studies of fasting. In addition, more detailed studies to investigate changes in sleep and the type and level of physical activities when fasting are propose