Responses to exercise, fluid, and energy balances during Ramadan in sedentary and active males

Ramadan Intermittent Fasting and Plasma Volume Variations in Individuals with Different Body Weights

Background: There is increasing awareness of the physiological effects of Ramadan intermittent fasting (RIF) in obese subjects. However, there are no data on the effects of RIF on plasma volume changes (ΔPV) in individuals with different body weights. Background and Objectives: This study investigated the effects of RIF on ΔPV in normal-weight (NW) and overweight (OW) adult men, and adult men with obesity (OB) and severe obesity (SO). Materials and Methods: Thirty-two male subjects (32) were divided into four groups (n = 8 per group) according to their body mass index (BMI): normal weight (NW) (BMI < 25 kg/m2; age = 27.4 ± 3.8), overweight (OW) (BMI between 25 and 29.9 kg/m2; age = 26.8 ± 3.7), obese subjects (OB) (BMI between 30 and 34.9 kg/m2; age = 25.6 ± 2.9), and severely obesity (SO) (BMI between 35 and 40 kg/m2; age = 24.0 ± 4.1). Blood samples were collected for 24 h on 4 different occasions, at T0 before the start of the Ramadan month, at T1 15 days after the start of Ramadan, at T2 one day after the end of Ramadan, and at T3 on the 21st day after the end of Ramadan to determine ΔPV. All groups completed their fasting rituals for the 30 days of Ramadan. Results: A significant group × time effect occurred for body mass (p = 0.001; ES = 0.53), BMI (p = 0.001; ES = 0.53), and body fat percentage (p = 0.001; ES = 0.52). Post hoc tests indicated reductions in body mass in OB and SO at T1 (p = 0.03; ES = 0.21 and p = 0.002; ES = 0.12) and T2 (p = 0.03; ES = 0.31 and p = 0.02; ES = 0.23), reductions in BMI in OB and SO at T1 (p = 0.04; ES = 0.35 and p = 0.03; ES = 0.42) and T2 (p = 0.03; ES = 0.52 and p = 0.005; ES = 0.48), and reductions in body fat percentage only in OB AT T1 (p = 0.002; ES = 0.31) and T2 (p = 0.001; ES = 0.17). A significant group × time effect occurred for hematocrit (p = 0.02; ES = 0.34), hemoglobin (p = 0.01; ES = 0.35), and ΔPV (p = 0.02; ES = 0.18). Post hoc tests indicated increases in hematocrit in OB at T2 (p = 0.03; ES = 0.36) and hemoglobin in OB and SO at T1 (p = 0.03; ES = 0.35 and p = 0.002; ES = 0.32) and T2 (p = 0.003; ES = 0.21 and p = 0.002; ES = 0.33). There were also increases in ΔPV in OB at T1 and T2 (p = 0.002; ES = 0.25 and p = 0.003; ES = 0.22) and in SO only at T2 (p = 0.02; ES = 0.37). Contrast analysis indicated that NW was significantly lower than the grand mean of OW, Ob, and SO for all anthropometric and PVV variables (all p < 0.05). Conclusions: The effects of RIF on ΔPV and anthropometric characters was greater in obese individuals compared to normal-weight and overweight participants, suggesting that the improvements in body composition and ΔPV produced by RIF could positively influence obesity.

Changes in energy and macronutrient intakes during Ramadan fasting: a systematic review, meta-analysis, and meta-regression

CONTEXT

Ramadan fasting (RF) is associated with various physiological and metabolic changes among fasting Muslims. However, it remains unclear whether these effects are attributable to changes in meal timing or changes in dietary energy and macronutrient intakes. Furthermore, the literature on the associations between RF, meal timing, and energy and macronutrient intakes is inconclusive.

OBJECTIVES

This systematic review aimed to estimate the effect sizes of RF on energy and macronutrient intakes (carbohydrates, protein, fats, dietary fiber, and water) and determine the effect of different moderators on the examined outcomes.

DATA SOURCES

The Cochrane, CINAHL, EMBASE, EBSCOhost, Google Scholar, PubMed/MEDLINE, ProQuest Medical, Scopus, ScienceDirect, and Web of Science databases were searched from inception to January 31, 2022.

DATA EXTRACTION

The studies that assessed energy, carbohydrate, protein, fat, fiber, and water intakes pre- and post-fasting were extracted.

DATA ANALYSIS

Of the 4776 identified studies, 85 relevant studies (n = 4594 participants aged 9-85 y) were selected. The effect sizes for the studied variables were as follows: energy (number of studies [K] = 80, n = 3343 participants; mean difference [MD]: -142.45; 95% confidence interval [CI]: -215.19, -69.71), carbohydrates (K = 75, n = 3111; MD: -23.90; 95% CI: -36.42, -11.38), protein (K = 74, n = 3108; MD: -4.21; 95% CI: -7.34, -1.07), fats (K = 73, n = 3058; MD: -2.03; 95% CI: -5.73, 1.67), fiber (K = 16, n = 1198; MD: 0.47; 95% CI: -1.44, 2.39), and water (K = 17, n = 772; MD: -350.80; 95% CI: -618.09, 83.50). Subgroup analyses showed age significantly moderated the 6 dietary outcomes, and physical activity significantly moderated water intake. There were significant reductions in energy, carbohydrate, and protein intakes during RF.

CONCLUSIONS

The change in meal timing rather than quantitative dietary intake may explain various physiological and health effects associated with RF.

Alteration in body water compartments following intermittent fasting in Ramadan

Concerning the health outcomes of intermittent fasting in Ramadan, loss of fat-free mass (FFM) and changes in the content of body water are of paramount importance. In this study, we aimed to assess the concomitant alterations in body water compartment and composition following Ramadan fasting in healthy individuals. We conducted an open-label cohort with longitudinal follow-up, involving 73 healthy medical staff who planned to fast for at least 20 consecutive days during Ramadan. The primary outcomes of the cohort were changes in parameters related to body composition and water content, which were measured using bioelectrical impedance analysis by InBody S10 (InBody, Seoul, South Korea). Based on the results, the participants' weight decreased significantly by approximately 1,030 g after the fasting period (p < 0.001). There was a significant reduction in the fat mass of an average 828 g (p < 0.001), which accounted for more than 80% of the weight loss. The decline in FFM was not significant (190 g; p = 0.234). The amount of total body water (TBW) and extracellular water (ECW) did not change, while intracellular water (ICW) decreased significantly by about 160 mL (p = 0.027). A strong correlation was observed between the reduction of phase angle and the increase in ECW/TBW ratio (R = -0.71, p < 0.001). Overall, our findings revealed a minimal amount of weight loss after Ramadan fasting, which was mainly due to the loss of fat mass. The parallel decrease in ICW and phase angle indicated impaired cell membrane integrity, with subsequent movement of water from the intracellular to the extracellular compartment.

Religious fasting and its impacts on individual, public, and planetary health: Fasting as a "religious health asset" for a healthier, more equitable, and sustainable society

Religious fasting is practiced by people of all faiths, including Christianity, Islam, Buddhism, Jainism, as well as Hinduism, Judaism, and Taoism. Individual/clinical, public, global, and planetary health has traditionally been studied as separate entities. Nevertheless, religious fasting, in conjunction with other religious health assets, can provide several opportunities, ranging from the individual to the population, environmental, and planetary levels, by facilitating and supporting societal transformations and changes, such as the adoption of healthier, more equitable, and sustainable lifestyles, therein preserving the Earth's systems and addressing major interconnected, cascading, and compound challenges. In this review, we will summarize the most recent evidence on the effects of religious fasting, particularly Orthodox and Ramadan Islamic fasting, on human and public health. Further, we will explore the potential effects of religious fasting on tackling current environmental issues, with a special focus on nutrition/food restriction and planetary health. Finally, specific recommendations, particularly around dietary intake during the fasting rituals, will be provided to ensure a sustainable healthy planet.

Exploring the Effects of Energy Constraints on Performance, Body Composition, Endocrinological/Hematological Biomarkers, and Immune System among Athletes: An Overview of the Fasting State

The Ramadan fasting period (RFP) means abstaining from consuming food and/or beverages during certain hours of the day—from sunrise to sunset. Engaging in exercise and sports during the RFP leads to the lipolysis of adipose tissue and an increase in the breakdown of peripheral fat, leading to an increase in fat consumption. The effects of the RFP on functional, hematological, and metabolic parameters needs further study as existing studies have reported contradictory results. The differences in the results of various studies are due to the geographical characteristics of Muslim athletes, their specific diets, and their genetics, which explain these variations. In recent years, the attention of medical and sports researchers on the effects of the RFP and energy restrictions on bodily functions and athletic performance has increased significantly. Therefore, this brief article examines the effects of the RFP on the immune system, body composition, hematology, and the functionality of athletes during and after the RFP. We found that most sporting activities were performed during any time of the day without being affected by Ramadan fasting. Athletes were able to participate in their physical activities during fasting periods and saw few effects on their performance. Sleep and nutritional factors should be adjusted so that athletic performance is not impaired.

Outcomes of a Medically Supervised Fasting Module on Healthy Females in a Controlled Residential Environment: A Brief Report

Background:

Fasting is being used as a therapeutic and cultural practice for millennia. There are numerous reports available on beneficial effects of fasting on various disease conditions. Despite the mounting evidence on fasting, little is known on its physiological effects in humans as most of the studies on physiological effects are done in animals.

Methods:

Twenty healthy female volunteers (mean age ± SD, 21.95 ± 2.52 years) participated in a 10-day fasting program, which has 1 preparatory day and 1 refeeding day (1,000 kcal) and 8 fasting days (500 kcal). All the participants consented to participate in the study. Blood parameters like complete blood count, renal function test, total iron binding capacity, lipid profile, liver profile, vitamins D and B12, thyroid function tests, glycated hemoglobin, and air blood gas test along with anthropometric measurements were taken on the first and last day.

Results:

All the parameters under the study have shown statistically significant changes (p < 0.05) except hemoglobin (p = 0.7) and non-high density lipoprotein (p = 0.32). Notable changes were the significant increase in vitamins D and B12 levels that signifies the homoeostatic potential of a fasting regimen.

Conclusion:

The result depicts the positive impact of fasting on various physiological parameters that warrants further studies on the safety of fasting in diverse diseases, especially the ones that have metabolic disarray as the root cause. Despite the limitation of the smaller sample size and lack of a control group, the results are encouraging to devise disease-specific fasting programs.

Microwave Hydration Monitoring: System Assessment Using Fasting Volunteers

Hydration is an important aspect of human health, as water is a critical nutrient used in many physiological processes. However, there is currently no clinical gold standard for non-invasively assessing hydration status. Recent work has suggested that permittivity in the microwave frequency range provides a physiologically meaningful metric for hydration monitoring. Using a simple time of flight technique for estimating permittivity, this study investigates microwave-based hydration assessment using a population of volunteers fasting during Ramadan. Volunteers are measured throughout the day while fasting during Ramadan and while not fasting after Ramadan. Comparing the estimated changes in permittivity to changes in weight and the time s fails to establish a clear relationship between permittivity and hydration. Assessing the subtle changes in hydration found in a population of sedentary, healthy adults proves difficult and more work is required to determine approaches suitable for tracking subtle changes in hydration over time with microwave-based hydration assessment techniques.

Effects of Ramadan and Non-ramadan Intermittent Fasting on Body Composition: A Systematic Review and Meta-Analysis

Intermittent fasting (IF) has gained popularity for body-composition improvement purposes. The aim of this systematic review and meta-analysis was to summarize the effects of Ramadan vs. non-Ramadan IF on parameters of body composition. We conducted a comprehensive search of peer-reviewed articles in three electronic databases: PubMed, Scopus, and Web of Science (published until May 2020). Studies were selected if they included samples of adults (≥18 years), had an experimental or observational design, investigated any type of IF and included body composition outcomes. Meta-analytical procedures were conducted when feasible. Sixty-six articles met the eligibility criteria. We found that non-Ramadan IF is effective for decreasing body weight (−0.341 (95% CI [−0.584, −0.098], p = 0.006), body mass index (−0.699, 95% CI [−1.05, −0.347], p < 0.001), and absolute fat mass (−0.447, 95% CI [−0.673, −0.221], p < 0.001). When contrasting pre- post-intervention data on fat-free mass between treatments and controls, group-differences were non-significant (p > 0.05). Conversely, we observed a significant increase in fat-free mass when comparing pre- to post-intervention in a within design fashion (0.306, 95% CI [0.133, 0.48], p = 0.001). Finally, despite being accompanied by dehydration, Ramadan IF is effective in decreasing body weight (−0.353; 95% CI [−0.651, −0.054], p = 0.02) and relative fat mass (−0.533; 95% CI [−1.025, −0.04], p = 0.034). Ramadan IF seems to implicate some beneficial adaptations in weight management, although non-Ramadan IF appears to be more effective in improving overall body composition.

Effects of Time-Restricted Feeding during Ramadan on Dietary Intake, Body Composition and Metabolic Outcomes

Ramadan fasting is a form of time-restricted feeding which combines a fast and feast period daily for a duration of one month every year. During Ramadan, Muslims abstain from food and drink consumption from dawn till sunset and this change in the meal schedule and frequency results in significant changes to the composition of the diet, such as energy and nutrient intake. These changes in dietary habits and their corresponding effects on cardiometabolic disease risk are compiled in this review. Ramadan fasting shows limited benefits to body composition via reductions in body mass in both healthy and obese individuals, although the results are often found to be transient and heterogeneous. There is, however, a more consistent improvement in blood lipid profile during Ramadan fasting, which often lasts beyond the Ramadan period. The results for glucose homeostasis, on the contrary, are more conflicting and inconclusive. The heterogeneity in the findings from the various studies can be generally attributed to cultural variations in dietary habits, differences in the duration of fasting due to seasonal/climatic differences at various geographical locations, age, gender and socioeconomic status, as well as other health and lifestyle factors of the various study populations.

Does Ramadan Observance Affect Cardiorespiratory Capacity of Healthy Boys?

Studies raising the issue of the effects of Ramadan observance (RO) on boys' 6-min walk test (6MWT) data are rare. The studies, which did not include control groups of non-fasters, presented contradictory results. This study aimed to compare the 6MWT data (6-min walk distance [6MWD; m, %predicted], heart rate [HR; bpm, % of maximal predicted HR]), oxy-hemoglobin saturation (Oxy-sat; %), systolic and diastolic blood pressures (SBP and DBP, respectively; mmHg) determined at rest (_Rest and at the end _End of the test) of a group of 22 healthy fasting boys (age: 12 to 15 years) with an age-matched non-fasting group (n = 10). The 6MWTs were performed during three experimental conditions (ECs): Pre-Ramadan, Mid-Ramadan, and Post-Ramadan. The two groups' 6MWT data for each EC were compared, and repeated factorial analysis of variance (2 groups vs. 3 ECs) was performed. Both groups had similar values of 6MWD (m, %predicted), HR_Rest or HR_End (bpm, % of maximal predicted HR), Oxy-sat_Rest, Oxy-sat_End, SBP_Rest, and DBP_Rest during the three ECs. Compared to the non-fasting group, the fasting group had significantly higher SBP_End (121 ± 10 vs. 130 ± 11) and DBP_End (72 ± 6 vs. 78 ± 7) determined during the Mid-Ramadan EC. No significant interactive effects of the groups (2) vs. ECs (3) was found for the 6MWD (%predicted; p = .809), HR_Rest (%, p = .555), HR_End (%, p = .964), Oxy-sat_Rest (p = .336), Oxy-sat_End (p = .389), SBP_Rest (p = .708), SBP_End (p = .548), DBP_Rest (p = .277), and DBP_End (p = .096). To conclude, in boys, RO does not impact the 6MWD, HR, or Oxy-sat, but it has minimal impact on the SBP_End and DBP_End.

Mendonca G. Effects of Intermittent Fasting on Specific Exercise Performance Outcomes: A Systematic Review Including Meta-Analysis

Intermittent fasting (IF) has been studied in athletes during Ramadan and in those willing to decrease adiposity while maintaining or increasing lean body mass. The purpose of this systematic review was to summarize the effects of IF on performance outcomes. We searched peer-reviewed articles in the following databases: PubMed, Web of Science and Sport Discus (up to December 2019). Studies were selected if they included samples of adults (≥18 years), had an experimental or observational design, investigated IF (Ramadan and time-restricted feeding (TRF)), and included performance outcomes. Meta-analytical procedures were conducted when feasible. Twenty-eight articles met the eligibility criteria. Findings indicated that maximum oxygen uptake is significantly enhanced with TRF protocols (SMD = 1.32, p = 0.001), but reduced with Ramadan intermittent fasting (Ramadan IF; SMD = −2.20, p < 0.001). Additional effects of IF may be observed in body composition (body mass and fat mass). Non-significant effects were observed for muscle strength and anaerobic capacity. While Ramadan IF may lead to impairments in aerobic capacity, TRF may be effective for improving it. As there are few studies per performance outcome, more research is needed to move the field forward.

Exercise Training and Fasting: Current Insights

Fasting is defined as the abstinence from consuming food and/or beverages for different periods of time. Both traditional and modern healthcare systems recommend fasting as a therapeutic intervention for the management of several chronic, non-infectious diseases. Exercising during a fasting state increases lipolysis in adipose tissue while also stimulating peripheral fat oxidation, resulting in increased fat utilization and weight loss. A key focus of this review is to assess whether endurance training performed while fasting induces specific training adaptations, where increased fat oxidation improves long-term endurance levels. Fasting decreases body weight, lean body and fat content in both trained and untrained individuals. Several studies indicate a broader impact of fasting on metabolism, with effects on protein and glucose metabolism in sedentary and untrained subjects. However, there are conflicting data regarding the effects of fasting on glucose metabolism in highly trained athletes. The effects of fasting on physical performance indicators also remain unclear, with some reporting a decreased performance, while others found no significant effects. Differences in experimental design, severity of calorie restriction, duration, and participant characteristics could, at least in part, explain such discordant findings. Our review of the literature suggests that there is little evidence to support the notion of endurance training and fasting-mediated increases in fat oxidation, and we recommend that endurance athletes should avoid high intensity training while fasting.

Clinical practice points for diabetes management during RAMADAN fast

Diabetes management during Ramadan is very crucial from the patient perspective as it can present significant risk of hypoglycemia and death when proper care is not taken. Moreover, managing diabetes in fasting Ramadan patients require different mechanisms than the routine diabetes management and pose significant challenge to the health care practitioners. Here we set forth to review the available literature of various clinical trials and studies on different antidiabetic agents in the context of Ramadan. On the basis of available evidence, we suggest that gliclazide is effective and it could be safely recommended in type 2 diabetic patients fasting during Ramadan.

Ramadan fasting does not adversely affect neuromuscular performances and reaction times in trained karate athletes

Background

The present study aimed to investigate the concomitant effects of Ramadan intermittent fast (RIF) and muscle fatigue on neuromuscular performances and reaction times in young trained athletes.

Methods

Eight karate players (17.2 ± 0.5 years) were tested on three sessions: during a control period (S1: one week before Ramadan), and during the first (S2) and the fourth week of RIF (S3). Dietary intake and anthropometric measurements were assessed before each session. During each test session, participants performed maximal voluntary isometric contractions (MVC) and a submaximal contraction at 75 % MVC until exhaustion (T_lim) of the right elbow flexors. Surface electromyography was recorded from biceps brachii muscle during MVC and T_lim. Simple (SRT) and choice (CRT) reaction times were evaluated at rest and just after T_lim in a random order.

Results

The total daily energy (S2: +19.5 %, p < 0.05; S3: +27.4 %, p < 0.01) and water (S2: +26.8 %, p < 0.01; S3: +23.2 %, p < 0.05) intake were significantly increased during RIF. However, neither body mass nor body mass index was altered by RIF (F_(2,14) = 0.80, p = 0.47 and F_(2,14) = 0.78, p = 0.48, respectively). In addition, T_lim (F_(2,14) = 2.53, p = 0.12), MVC (F_(2,14) = 0.51, p = 0.61) and associated electrical activity (F_(2,14) = 0.13, p = 0.88) as well as neuromuscular efficiency (F_(2,14) = 0.27, p = 0.76) were maintained during RIF. Moreover, neither SRT nor CRT was affected by RIF (F_(2,14) = 1.82, p = 0.19 and F_(2,14) = 0.26, p = 0.78, respectively) or neuromuscular fatigue (F_(1,7) = 0.0002, p = 0.98 and F_(1,7) = 3.78, p = 0.09, respectively).

Conclusions

The present results showed that RIF did not adversely affect the neuromuscular performances and anthropometric parameters of elite karate athletes who were undertaking their usual training schedule. In addition, neither RIF nor neuromuscular fatigue poorly affects reaction times in elite karate athletes.

Effect of Ramadan intermittent fasting on selective fitness profile parameters in young untrained Muslim men

Background

The present study was aimed at investigating the effects of sleep deprivation and dietary irregularities during Ramadan intermittent fasting (RIF) on selective fitness profile parameters in young untrained male Muslim individuals.

Methods

77 untrained Muslim men were recruited in the study. They were divided into the experimental group (EG; n=37, age: 22.62±1.77 years) and the control group (CG; n=40, age: 23.00±1.48 years). EG was undergoing RIF while CG abstained. Aerobic fitness, anaerobic capacity or high-intensity efforts (HIEs), agility, flexibility, vertical jump height and handgrip strength were measured on 8 separate occasions—15 days before RIF, 7 days before RIF, 1st day of RIF, 7th day of RIF, 15th day of RIF, 21st day of RIF, last day of RIF and 15 days after RIF.

Results

Aerobic fitness and HIE showed a significant difference (p<0.05) during RIF in EG. Agility and flexibility score showed a significant decrease in EG during RIF, whereas changes in the vertical jump score (VJT) and handgrip strength were statistically insignificant. Studied parameters showed an insignificant variation in CG during RIF. Aerobic fitness, HIEs, agility and flexibility showed a significant intergroup variation during different experimental trials.

Conclusions

The present investigation revealed that RIF had adverse effects on aerobic fitness, HIEs, agility and flexibility of young untrained Muslims of Kolkata, India. VJT, waist-hip ratio and handgrip strength were not affected by RIF in the studied population. Mild but statistically insignificant reduction in body mass was also reflected after the mid-Ramadan week.

Microstructural effects of Ramadan fasting on the brain: a diffusion tensor imaging study

PURPOSE

We aimed to examine whether the brain displays any microstructural changes after a three-week Ramadan fasting period using diffusion tenson imaging.

METHODS

This study included a study and a control group of 25 volunteers each. In the study group, we examined and compared apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values of the participants during (phase 1) and after (phase 2) a period of fasting. The control group included individuals who did not fast. ADC and FA values obtained in phase 1 and phase 2 were compared between the study and control groups.

RESULTS

In the study group, ADC values of hypothalamus and, to a lesser extent, of insula were lower in phase 1 compared with phase 2 and the control group. The FA values of amygdala, middle temporal cortex, thalamus and, to a lesser extent, of medial prefrontal cortex were lower in phase 1 compared with phase 2 and the control group. Phase 2 ADC and FA values of the study group were not significantly different compared with the control group at any brain location.

CONCLUSION

A three-week Ramadan fasting period can cause microstructural changes in the brain, and diffusion tensor imaging enables the visualization of these changes. The identification of brain locations where changes occurred in ADC and FA values during fasting can be helpful in diagnostic imaging and understanding the pathophysiology of eating disorders.

A Prospective Study of the Physiological and Neurobehavioral Effects of Ramadan Fasting in Preteen and Teenage Boys

BACKGROUND

Intermittent fasting during the month of Ramadan, although not obligatory, is commonly practiced by Muslim children.

OBJECTIVE

Our aim was to describe the effects of Ramadan fasting on various physiological and neurobehavioral measures in preteen and teenaged boys.

DESIGN

We conduced a prospective cohort study during Ramadan, observed from August 9 to September 11, 2010.

PARTICIPANTS

Eighteen healthy Muslim boys (mean age±standard deviation 12.6±1.5 years) were recruited and assessed before, during (1st and 4th weeks), and after Ramadan. Subjects were classified as preteens (aged 9 to 12 years) or teens (aged 13 to 15 years).

INTERVENTION

On each clinic visit, participants completed a match-to-sample test, a spatial planning and working memory task, and a working memory capacity test using the Cambridge Neuropsychological Test Automated Battery. Participants were also assessed for their sleep patterns, daily energy expenditure, and dietary intake. Body composition was determined using a dual-energy x-ray scan. Complete blood count, lipid profile analysis, and iron indices were conducted.

MAIN OUTCOME MEASURES

We measured morphologic, metabolic, and neurobehavioral parameters.

STATISTICAL ANALYSES

A linear mixed model was used to assess changes in outcome measures. Post hoc pairwise comparisons were performed as necessary with Bonferroni adjustment.

RESULTS

Within 1 week of fasting, there was a drop in body fat only in preteens (P=0.001). Reported fat (P=0.004) and protein intake (P=0.037) was higher during Ramadan, but energy expenditure did not change. By the end of Ramadan, there was a significant reduction in hemoglobin (mean±standard error -0.48±0.4 mmol/L) and serum iron (-25.7±31.8 μg/dL [-4.6±5.7 μmol/L]) levels. During week 4, total sleep duration decreased by 1.8 hours. At week 4, performance on the spatial planning and working memory task and working memory capacity test increased significantly (P=0.002), while match-to-sample test performance declined in preteens only (P=0.045).

CONCLUSIONS

Ramadan fasting was associated with significant changes in body composition, dietary intake, and sleep patterns. Reductions in attention and iron indices were observed in preteens only.

Effects of Ramadan on physical capacities of North African boys fasting for the first time

INTRODUCTION

Most of the literature related to the effects of Ramadan fasting on physical performance has focused on adults, and only three studies have examined its impact on children's physical performance.

AIMS

To examine the effects of Ramadan fasting on first-time fasting boys' performance in short-term explosive exercises [vertical and horizontal jump tests (VJT and HJT), 20-m and 30-m sprints and medicine-ball throw (MBT)], as well as in sub-maximal endurance [6-min walking distance (6MWD) measured during the 6-min walk test (6MWT)].

METHODS

Eighteen Tunisian boys [mean±standard deviation (SD) of age and body mass (BM): 11.9±0.8 y and 55.4±18.2 kg, respectively] were included. The experimental design comprised four testing phases: 2-weeks before Ramadan (BR), the end of the second week (R2) and the fourth week (R4) of Ramadan, and 10-12 days after the end of Ramadan (AR). At each phase, boys performed two test sessions in the afternoon (15:00-17:00 h) interrupted by 48 h of recovery (first test session: BM, VJT, HJT, and 20-m and 30-m sprint tests; second session: MBT and 6MWT). The study was conducted during the summer of 2012 from July 5 to August 29.

RESULTS

6MWDs (m) were significantly shorter during R2 (652±101) and R4 (595±123) compared to BR (697±86) and came back to baseline values AR. BM (kg) mean±SD did not significantly change during R2 (52±15) and during R4 (53±15) compared to BR (55±17), and short-term explosive performances were unchanged throughout the study.

CONCLUSION

In non-athletic children, first-ever Ramadan fasting impairs sub-maximal aerobic capacity but has no effect on BM or short-term explosive performance.

Islamic fasting and weight loss: a systematic review and meta-analysis

OBJECTIVE

Studies on the effects of Ramadan fasting on weight changes have been contradictory. We brought together all published data to comprehensively examine the effects in a systematic review and meta-analysis.

DESIGN

Relevant studies were obtained through searches of PubMed and CINAHL and by independent screening of reference lists and citations without any time restriction. All searches were completed between October and November 2011.

SETTING

Changes in body weight during and after Ramadan were extracted from thirty-five English-language studies and were meta-analysed. Most of the studies were conducted in West Asia (n 19); the remainder were conducted in Africa (n 7), East Asia (n 3) and North America/Europe (n 4).

SUBJECTS

Healthy adults.

RESULTS

Fasting during Ramadan resulted in significant weight loss (-1·24 kg; 95% CI -1·60, -0·88 kg). However, most of the weight lost was regained within a few weeks and only a slight decrease in body weight was observed in the following weeks after Ramadan compared with that at the beginning of Ramadan. Weight loss at the end of Ramadan was significant in both genders (-1·51 kg for men and -0·92 kg for women); but again the weight loss lasted no longer than 2 weeks after Ramadan. Weight loss during Ramadan was greater among Asian populations compared with Africans and Europeans.

CONCLUSIONS

Weight changes during Ramadan were relatively small and mostly reversed after Ramadan, gradually returning to pre-Ramadan status. Ramadan provides an opportunity to lose weight, but structured and consistent lifestyle modifications are necessary to achieve lasting weight loss.

Intraday blood rheological changes induced by Ramadan fasting in sickle cell trait carriers

The goal of the present study was to test whether fasting during the holy period of Ramadan may disturb blood rheology in sickle cell trait (SCT) carriers more than in a group of subjects with normal hemoglobin. Twenty African male students participated in the study: 10 SCT carriers and 10 subjects with normal hemoglobin (CONT). Biochemical parameters (plasma glucose and lipids levels), hematocrit, blood viscosity, and urine specific gravity were measured in the two groups on the 14th day of the Ramadan period (Ramadan condition) and 6 wks after the end of Ramadan (baseline condition). All the measurements were performed twice for each experimental day to measure intraday variation: 8:00 and 18:00 h. Plasma glucose level and lipid profile were not significantly different between the two groups. Although Ramadan did not affect the lipid profile, the plasma glucose concentration was lower during the Ramadan period compared with the baseline condition in the two groups. Hematocrit and urine specific gravity did not differ between the two groups and was greater in the evening than in the morning, independently of the condition. SCT carriers had higher blood viscosity than the CONT group. However, whereas blood viscosity remained unchanged through the day in the CONT group, whatever the condition, SCT carriers were characterized by a large increase of blood viscosity in the evening during the Ramadan period, indicating higher risk for microcirculatory blood flow impairments. Specific medical recommendations are needed for SCT carriers engaged in religious fasting.

Does Ramadan affect the risk of injury in professional football?

OBJECTIVE

To investigate whether fasting during Ramadan influences injury incidence in professional Muslim and non-Muslim footballers.

DESIGN

Prospective cohort study.

SETTING

Professional First Division League of Qatar.

PARTICIPANTS

About 527 male football players (462 Muslim and 65 non-Muslim) from 7 league clubs (first year of data collection) and 8 clubs (second and third years).

INTERVENTIONS

Daily collection of training and match exposure from August 2008 until April 2011 by club medical staff. Injuries during training and match play were recorded on standardized injury cards.

MAIN OUTCOME MEASURES

Injury incidence was calculated as number of injuries per hour exposed to risk, and expressed as rate per 1000 hours. The probability of injury for different Arabic months between Muslims and non-Muslims was calculated using Generalized Estimating Equations (GEEs).

RESULTS

There was no significant difference in total, match, and training injury incidence between the Ramadan and non-Ramadan periods. Non-Muslim footballers had a significantly higher injury incidence rate than Muslim footballers both during Ramadan (8.5 vs 4.0 injuries/1000 hours, P = 0.009) and non Ramadan (6.6 vs 4.9 injuries/1000 hours, P = 0.004) periods. The GEE analysis revealed that after adjusting for age and random factors (month and club), the probability of match injury among non-Muslims was the highest in Ramadan and the 2 consecutive following months (adjusted odds ratio of injury among non-Muslims compared with Muslims was 3.7 [95% confidence interval (CI), 1.7-7.9], P = 0.001 during Ramadan (ninth) month; 2.4 (95% CI, 1.1-4.9), P = 0.021 during 10th month; and 2.7 (95% CI, 1.2-5.8), P = 0.013 during 11th month). Finally, there was no change in injury patterns over the months of the Islamic calendar.

CONCLUSIONS

Ramadan does not impact injury incidence for Muslim footballers in Qatar, suggesting the current adjustments and scheduling of football activities during Ramadan are sufficient. The increased match injury among non-Muslims during and 2 months post-Ramadan may suggest less effective coping strategies.

Effects of Ramadan fasting on peptic ulcer disease as diagnosed by upper gastrointestinal endoscopy

BACKGROUND AND STUDY AIMS

The diagnostic methods such as upper gastrointestinal endoscopy (UGE) have played an important role in the evaluation of peptic ulcer (PU). Every year, millions of Muslims fast in Ramadan month. The aim of this study was to evaluate the effect of fasting on PU via UGE.

PATIENTS AND METHODS

A total of 321 patients in the period from 2009 to 2011, who underwent UGE as a diagnostic work-up mainly for epigastric pain, were analysed. Patients were divided into three groups: Patients who have been evaluated by UGE, in the month just before Ramadan (group I, n=69), in Ramadan month (group II, n=132) and in the month just after Ramadan (group III, n=120). Continuous data were expressed as the mean±SD, and were compared with one-way analysis of variance (ANOVA) test amongst groups. Categorical data were given as percentages and were compared with the chi-squared test.

RESULTS

Epigastric pain was the most common indication for referral in each group. Interestingly, the indication 'bleeding' was found to be the least in group II, but was far from statistical significance. The highest prevalence of duodenal ulcers and duodenitis was found in group II; the differences to the other groups were statistically significant.

CONCLUSION

Duodenal ulcers and duodenitis were found more during Ramadan month. We recommend that, the patients with epigastric pain may fast by taking their medications.

Effect of ramadan fasting on body water status markers after a rugby sevens match

Purpose

To evaluate the effect of Ramadan fasting on body water status markers of rugby players at basal condition and following a simulation of rugby sevens match.

Methods

Twelve recreational rugby sevens players played three matches: one day before Ramadan (before Ramadan), at the end of the first week of Ramadan (Beg-R) and at the end of Ramadan (End-R). Before and immediately after each match, body weight was determined and blood samples were taken for the measurement of body water status markers. Total body water was measured with an impedancemeter only before matches.

Results

At rest, an increase in hematocrit (+4.4%, P=0.03), hemoglobin (+3.4%, P=0.01) and plasma osmolarity (+2.8%, P<0.001) was noticed at End-R compared to before Ramadan. Total body water measured before Ramadan did not differ significantly from that of Ramadan. After the match, values of hematocrit and plasma osmolarity increased significantly at End-R (+1.4%, P=0.02; +3.1%, P<0.001 respectively) compared to before Ramadan. Although, hemoglobin measured after matches occurring during Ramadan did not differ from those of before Ramadan. In response to matches, the change of percentage of body water status markers did not differ during each period of the investigation.

Conclusions

The present results show that Ramadan fasting induces dehydration at basal conditions. Also, rugby sevens match played during Ramadan did not exacerbate the magnitude of responses to matches of blood and body water status markers.

Ramadan and Its Effect on Fuel Selection during Exercise and Following Exercise Training

Fasting induces short-term physiological adaptations which spare the body's remaining carbohydrate stores and mobilize lipid stores to provide a substitute fuel for many tissues and organs, especially skeletal muscle. Rodent studies show that regular occurrence of fasting then refeeding, stimulates adaptations in muscle which make the animal better placed to withstand a further period of fasting by possessing a better ability to oxidise lipid.This review explores the research describing these adaptations, with an emphasis on Ramadan, a human model of repeated fasting/refeeding. Separately, a single bout of endurance exercise places similar metabolic stress on the body as fasting since the exercising muscle must reduce its use of carbohydrate and utilize lipid more readily as exercise progresses. Not surprisingly therefore, adaptations in muscle to repeated bouts of endurance exercise (endurance training) are similar to those seen with repeated fasting/refeeding. Superimposing the stressors of repeated fasting/refeeding and exercise training, and subsequent adaptations to the muscle and exercise response, are examined by describing the published research which has investigated the situation where athletes continue their training whilst participating in Ramadan.

Effects of ramadan fasting on biochemical and anthropometric parameters in physically active men

Purpose

The aim of this study was to assess the effects of Ramadan fasting on several biochemical and anthropometric parameters in physically active men by comparing fasters and nonfasters before, during, and after Ramadan.

Methods

Eighteen physically active men (10 fasters and 8 nonfasters) participated in this study. Subjects visited the laboratory for a total of four sessions on the following occasions: three days before Ramadan (Bef-R), the 15^th day of Ramadan (Mid-R), the 29^th day of Ramadan (End-R), and 21 days after Ramadan (Post-R). During each session, subjects underwent anthropometric measurements, completed a dietary questionnaire and provided a fasting blood sample.

Results

Body weight and body fat percentage decreased in fasters by 1.9% (P<0.001) and 6.2% (P=0.003), respectively, but increased in nonfasters by 2.2% (P<0.001) and 10.2% (P=0.001), respectively, from Bef-R to End-R. Fasters’ hematocrit and hemoglobin increased by 5.3% (P<0.001) and 6.3% (P=0.01), respectively, from Bef-R to End-R, while neither of these parameters changed in nonfasters. Fasters experienced an increase in the following parameters from Bef-R to End-R: urea (8.7%; P<0.001), creatinine (7.5%; P<0.001), uric acid (12.7%; P<0.001), serum sodium (1.9%; P<0.001), serum chloride (2.6%; P<0.001) and high-density lipoprotein cholesterol (27.3%; P<0.001). Of these parameters, only creatinine increased (4.4%; P=0.01) in nonfasters.

Conclusion

We conclude that Ramadan fasting lowers body weight and body fat percentage and can elevate high-density lipoprotein cholesterol in physically active men. However, practicing aerobic exercise during a hot and humid Ramadan month can induce a state of dehydration marked by an increase in some renal function markers and serum electrolytes.

Effect of ramadan fasting on body composition and physical performance in female athletes

Purpose

The aim of this study was to determine the effect of Ramadan fasting on body composition, calorie intake and physical performance in young female athletes undertaking training sessions during Ramadan.

Methods

Twelve voluntary female athletes (15-27 years old) were assigned to the research. A prospective study was conducted to investigate the athletes on four different occasions: one week before Ramadan (T1), the second (T2) and fourth (T3) weeks of Ramadan, and two weeks after the end of Ramadan (T4). Food intake, body composition and physical performance (agility, balance and explosive leg power) were investigated on each occasion. Further, Physical performance was assessed by agility, vertical jump and balance tests.

Results

There was a significant main effect for time for body composition indices. A significant decrease was observed in weight (P=0.01) and body mass index (BMI) (P=0.01) in T2 compared with T1, further decrease in weight (P<0.001) and BMI (P<0.001) was observed in T3 compared to T1. Calorie intake decreased significantly in T3 compared with T1 (P=0.008), and increased significantly in T4 compared with T3 (P=0.04). There was a significant main effect for time for agility performance (P=0.03), but no significant main effect for time was observed for vertical jumping (P=0.1) and balance performance (P=0.3).

Conclusions

This study has found that Ramadan fasting could affect the body composition, but not physical performance in female athletes during Ramadan.

Investigating Two Different Training Time Frames during Ramadan Fasting

Purpose

Muslim athletes may continue training and competing while they are fasting. There is a concern about negative effects of fasting on sports performance. This study aimed to investigate the influence of two training time frames on athletes’ body composition and performance during Ramadan fasting.

Methods

An observational study was conducted and thirty four male volunteer athletes from different sports including volleyball, karate, taekwondo and football were assigned in two groups. The first group included 14 elite athletes who during Ramadan voluntarily participated in training sessions at 1 hour before Iftar (BI) and the second group of 20 elite athletes who during Ramadan participated in training sessions at 3 hours after Iftar (AI). Testing was performed one week before; in the first and fourth weeks of Ramadan and one week after Ramadan. Weights, heights and skinfold thickness were assessed at each time point and body mass index was calculated. Each player was assessed for agility and explosive strength as well.

Results

The mean weight and body mass index of both groups decreased significantly during Ramadan (P<0.001). Performance variables were not negatively affected by fasting in BI or AI group athletes.

Conclusions

Weight reduction might come with either BI or AI training schedules in Ramadan. Daytime or evening training did not inversely affect the agility and power performances in a group of elite athletes during Ramadan fasting.

The implications of Ramadan fasting for human health and well-being

Islamic Ramadan is a 29-30 day fast in which food, fluids, medications, drugs and smoking are prohibited during the daylight hours which can be extended between 13 and 18 h · day(-1) depending on the geographical location and season. The majority of health-specific findings related to Ramadan fasting are mixed. The likely causes for these heterogeneous findings lie in the amount of daily time of fasting, number of subjects who smoke, take oral medications, and/or receive intravenous fluids, in the type of food and eating habits and in changes in lifestyle. During Ramadan fasting, glucose homeostasis is maintained by meals taken during night time before dawn and by liver glycogen stores. Changes in serum lipids are variable and depend on the quality and quantity of food intake, physical activity and exercise, and changes in body weight. Compliant, well-controlled type II diabetics may observe Ramadan fasting, but fasting is not recommended for type I, noncompliant, poorly controlled and pregnant diabetics. There are no adverse effects of Ramadan fasting on respiratory and cardiovascular systems, haematologic profile, endocrine, and neuropsychiatric functions.

CONCLUSIONS

Although Ramadan fasting is safe for all healthy individuals, those with various diseases should consult their physicians and follow medical and scientific recommendations.

The effects of Ramadan intermittent fasting on athletic performance: recommendations for the maintenance of physical fitness

The behavioural modifications that accompany Ramadan intermittent fasting (RIF) are usually associated with some alterations in the metabolic, physiological, and psychological responses of athletes that may affect sport performance. Muslim athletes who are required to train and/or compete during the month-long, diurnal fast must adopt coping strategies that allow them to maintain physical fitness and motivation if they are to perform at the highest level. This updated review aims to present the current state of knowledge of the effects of RIF on training and performance, focusing on key-factors that contribute to the effects of Ramadan on exercise performance: energy restriction, sleep deprivation, circadian rhythm perturbation, dehydration, and alterations in the training load. The available literature contain few studies that have examined the effects of RIF on physical performance in athletes and, to date, the results are inconclusive, so the effects of RIF on competition outcomes are not at present wholly understood. The diverse findings probably indicate individual differences in the adaptability and self-generated coping strategies of athletes during fasting and training. However, the results of the small number of well-controlled studies that have examined the effects of Ramadan on athletic performance suggest that few aspects of physical fitness are negatively affected, and where decrements are observed these are usually modest. Subjective feelings of fatigue and other mood indicators are often cited as implying additional stress on the athlete throughout Ramadan, but most studies show that these factors may not result in decreases in performance and that perceived exercise intensity is unlikely to increase to any significant degree. Current evidence from good, well-controlled research supports the conclusion that athletes who maintain their total energy and macronutrient intake, training load, body composition, and sleep length and quality are unlikely to suffer any substantial decrements in performance during Ramadan. Further research is required to determine the effect of RIF on the most challenging events or exercise protocols and on elite athletes competing in extreme environments.

The impact of Ramadan observance upon athletic performance

Ramadan observance requires a total abstention from food and drink from sunrise to sunset for a period of one month. Such intermittent fasting has only minor effects upon the overall nutrition and physiological responses of the general sedentary population. Larger meals are consumed at night and in the early morning. Body mass usually remains unchanged, the total energy intake remains roughly constant, and there is little alteration in the relative consumption of protein, fats and carbohydrates. However, Ramadan observance may be of greater consequence for the training and performance of the competitive athlete, particularly when the festival is celebrated in the hotter part of the year and daylight hours are long, as is the case for the 2012 Summer Olympic Games in London, England. The normal sleeping time then tends to be shortened, and blood sugar and tissue hydration decrease progressively throughout the hours of daylight. Some limitation of anaerobic effort, endurance performance and muscle strength might be anticipated from the decrease in muscle glycogen and body fluid reserves, and a reduced blood glucose may cause a depressed mood state, an increased perception of effort, and poorer team work. This review considers empirical data on the extent of such changes, and their likely effect upon anaerobic, aerobic and muscular performance, suggesting potential nutritional and behavioral tactics for minimizing such effects in the Muslim competitor.

Impact of caloric and dietary restriction regimens on markers of health and longevity in humans and animals: a summary of available findings

Considerable interest has been shown in the ability of caloric restriction (CR) to improve multiple parameters of health and to extend lifespan. CR is the reduction of caloric intake - typically by 20 - 40% of ad libitum consumption - while maintaining adequate nutrient intake. Several alternatives to CR exist. CR combined with exercise (CE) consists of both decreased caloric intake and increased caloric expenditure. Alternate-day fasting (ADF) consists of two interchanging days; one day, subjects may consume food ad libitum (sometimes equaling twice the normal intake); on the other day, food is reduced or withheld altogether. Dietary restriction (DR) - restriction of one or more components of intake (typically macronutrients) with minimal to no reduction in total caloric intake - is another alternative to CR. Many religions incorporate one or more forms of food restriction. The following religious fasting periods are featured in this review: 1) Islamic Ramadan; 2) the three principal fasting periods of Greek Orthodox Christianity (Nativity, Lent, and the Assumption); and 3) the Biblical-based Daniel Fast. This review provides a summary of the current state of knowledge related to CR and DR. A specific section is provided that illustrates related work pertaining to religious forms of food restriction. Where available, studies involving both humans and animals are presented. The review includes suggestions for future research pertaining to the topics of discussion.

Effects of ramadan fasting on body composition, aerobic performance and lactate, heart rate and perceptual responses in young soccer players

The purpose of this study was to examine the effects of Ramadan fasting on body composition, aerobic exercise performance and blood lactate, heart rate and perceived exertion in regularly trained young soccer players. Sixteen male soccer players participated in this study. Mean age, stature, body mass and training age of the players were 17.4±1.2 years, 175.4±3.6 cm, 69.6±4.3 kg and 5.1±1.3 years, respectively. During the Ramadan period, all subjects voluntarily chose to follow the fasting guidelines and abstained from eating and drinking from sunrise to sunset. Body composition, hydration status, dietary intake and sleep duration were assessed on four occasions: before Ramadan, at the beginning of Ramadan, at the end of Ramadan and 2 weeks after the end of Ramadan. On each occasion, aerobic exercise performance and blood lactate, heart rate and rating of perceived exertion responses of players were also determined during an incremental running test. Repeated measures of ANOVA revealed that body mass, percentage of body fat, fat-free mass, hydration status, daily sleeping time and daily energy and macronutrient intake of players did not vary significantly throughout the study period (p>0.05). However, players experienced a small but significant decrease in skinfold thicknesses over the course of the study (p<0.05). Although ratings of perceived exertion at submaximal workloads increased during Ramadan (p<0.05), blood lactate and heart rate responses had decreased by the end of Ramadan (p<0.05). In line with these changes, peak running performance and running velocity at anaerobic threshold also improved by the end of Ramadan (p<0.05). Improvements in aerobic exercise performance with time were probably due to the effects of pre-season training program that was performed after the break of the fast (Iftar) during the month of Ramadan. The results of the present study suggest that if regular training regimen, body fluid balance, daily energy intake and sleep duration are maintained as before Ramadan, Ramadan fasting does not have detrimental effects on aerobic exercise performance or body composition in young soccer players.

Effect of fasting on voice in males

PURPOSE OF THE STUDY

The aim of the study was to study how fasting between 12 and 14 hours affects voice production.

STUDY DESIGN

This is a prospective study of male subjects.

MATERIAL AND METHOD

A total of 26 healthy male subjects were recruited for the study. The age varied between 22 and 50 years with a mean of 28 years. Exclusion criteria included hoarseness at the time of presentation, history of recent upper respiratory tract infection, or microlaryngeal surgery. Subjects were evaluated while fasting and nonfasting. Each subject was asked about vocal fatigue and ease of phonation. This was followed by acoustic analyses and laryngeal videostroboscopy.

RESULTS

The incidence of vocal fatigue was not higher while fasting compared to nonfasting (P = 1.00). Phonatory effort was significantly greater during fasting (P < .001). Fifty percent of the subjects had an increase in their phonatory effort. There was a significant decrease in the habitual pitch, voice turbulence index, and noise-to-harmonic ratio (P = .018, .045, and .001, respectively). There were no laryngeal videostroboscopic changes.

CONCLUSION

Fasting in males results in an increase in phonatory effort. These phonatory changes may be secondary to dehydration as well as overall neuromuscular fatigability.

The impact of religious fasting on human health

The past two decades have seen a rise in the number of investigations examining the health-related effects of religiously motivated fasts. Islamic Ramadan is a 28 - 30 day fast in which food and drink are prohibited during the daylight hours. The majority of health-specific findings related to Ramadan fasting are mixed. The likely causes for these heterogeneous findings are the differences between studies in the following: 1) the amount of daily fasting time; 2) the percentage of subjects who smoke, take oral medications, and/or receive intravenous fluids; and 3) the subjects' typical food choices and eating habits. Greek Orthodox Christians fast for a total of 180 - 200 days each year, and their main fasting periods are the Nativity Fast (40 days prior to Christmas), Lent (48 days prior to Easter), and the Assumption (15 days in August). The fasting periods are more similar than dissimilar, and they can each be described as a variant of vegetarianism. Some of the more favorable effects of these fasts include the lowering of body mass, total cholesterol, LDL-C, and the LDL-C/HDL-C ratio. The Biblical-based Daniel Fast prohibits the consumption of animal products, refined carbohydrates, food additives, preservatives, sweeteners, flavorings, caffeine, and alcohol. It is most commonly partaken for 21 days, although fasts of 10 and 40 days have been observed. Our initial investigation of the Daniel Fast noted favorable effects on several health-related outcomes, including: blood pressure, blood lipids, insulin sensitivity, and biomarkers of oxidative stress. This review summarizes the health-specific effects of these fasts and provides suggestions for future research.

Effects of Ramadan intermittent fasting on sports performance and training: a review

The month-long diurnal Ramadan fast imposes a major challenge to Islamic athletes. Sporting events are programmed throughout the year, with the result that training and competition are often scheduled during Ramadan. The small numbers of well-controlled studies that have examined the effects of Ramadan on athletic performance suggest that few aspects of physical fitness are negatively affected, and only modest decrements are observed. Whereas subjective feelings of fatigue and other mood indicators are often cited as implying additional stress on the athlete throughout Ramadan, most studies show these measures may not be reflected in decreases in performance. The development and early implementation of sensible eating and sleeping strategies can greatly alleviate the disruptions to training and competitiveness, thus allowing the athlete to perform at a high level while undertaking the religious intermittent fast. Nevertheless, further research is required to understand the mechanisms and energy pathways that allow athletes to maintain their performance capacities during Ramadan, and which factors are responsible for the observed decrements in performance of some individuals.

The F-MARC study on Ramadan and football: research design, population, and environmental conditions

Ramadan is a month of penance during which Muslims take food or drink only after sunset and before the sun rises. This fast can present a considerable challenge to the Muslim athlete. Sports performance in those who observe Ramadan and those who do not has not been formally compared. Four Tunisian junior football squads participated in the study, and it was the individual's choice whether they observed the Ramadan fast. In this study, 64 players fasted while 36 players did not. Players completed daily questionnaires on perception of training difficulty before and during Ramadan. Anthropometric data were recorded 3 weeks before Ramadan, during the second and fourth weeks of Ramadan, and into the third week after Ramadan. Performance tests (sprint, leg power, agility, aerobic endurance, football-specific skills) were also measured on these test days. Nutritional intake was recorded by recall three times during each phase of the study. Haematological and biochemical analyses were performed on a 7-ml blood sample taken from each participant on each of the test days. Sweat samples were collected during a training session in the third week of Ramadan, when heart rate was also measured. The data analyses are presented and discussed elsewhere in this issue.

The effect of participation in Ramadan on substrate selection during submaximal cycling exercise

This study was undertaken to investigate whether or not substrate selection during exercise is altered with participation in Ramadan, and whether or not this alteration is influenced by exercise intensity. Eight men (21-41 years) exercised on an electronically braked cycle ergometer at three 10-min workloads (45, 60 and 75% VO(2peak)): (1) the week before Ramadan; (2) the end of the first week of Ramadan and (3) the final week of Ramadan. Four subjects were unable to complete the final 10-min (75% VO(2peak)) workload during Ramadan. During the two lower workloads, exercise RER significantly decreased during Ramadan (p<0.01) and there was a significant effect of Ramadan on the increase in RER with increased workload (p=0.041). Post hoc contrasts revealed only that RER during exercise at the end of the first week was significantly lower (p<0.01) than pre-Ramadan. Rate of lipid oxidation increased from 0.18gmin(-1)+/-0.22 to 0.31gmin(-1)+/-0.28 by the first week of Ramadan (p<0.01), the effect reversed by the final week (0.23gmin(-1)+/-0.22) (p=0.02). Although body weight declined during Ramadan (from 71.1kg+/-6.9 to 69.8kg+/-7.3, p=0.02), percentage body fat, measured via underwater weighing, did not change. In conclusion, daily fasting during Ramadan induces changes in substrate selection during submaximal exercise within 1 week, but these changes are moderated with continued daily fasting. However, changes in anthropometric variables reflect a net energy deficit during Ramadan which may have mediated the observed increased lipid oxidation during submaximal exercise.

The effect of the Ramadan fast on physical performance and dietary habits in adolescent soccer players

The purpose of this study was to examine the effect of the Ramadan fast on performance capacities, dietary habits, and the daily behavioral patterns in adolescent (14-16-year-old) soccer players. Nineteen male players performed a series of fitness tests before and at the end of Ramadan fast. Caloric intake, physical activity pattern and sleep habits were evaluated during the week before the Ramadan fast and during the last week of the Ramadan fast. The fast resulted in a significant reduction in aerobic capacity [3,000 m run time (mean +/- SD): 812.8 +/- 73.3 s vs. 819.9 +/- 73.4 s, P < 0.001], speed endurance (Sum 6 x 40 m run time: 46.36 +/- 1.36 s vs. 46.73 +/- 1.31 s, P < 0.001, and performance decrement: 9.0 +/- 1.5% vs. 9.5 +/- 1.7%, P < 0.05), and jumping performance (44.8 +/- 4.5 cm vs. 44.0 +/- 4.5 cm, P < 0.05), but had no significant effect on sprint performance (7.38 +/- 0.25 s vs. 7.40 +/- 0.26 s, P = 0.20) or agility (4 x 10 m shuttle run time: 9.53 +/- 0.35 s vs. 9.55 +/- 0.37 s, P = 0.26). Daily intense physical activity was significantly reduced during Ramadan (6.4 +/- 0.2 h/week vs. 4.5 +/- 0.1 h/week, P < 0.005). There were no significant differences in total caloric intake (3,012 +/- 412 kcal/day vs. 3240 +/- 348 kcal/day, P = 0.39) or total daily sleeping hours (8.6 +/- 0.7 h/day vs. 8.6 +/- 0.5 h/day, P = 0.80) between Ramadan and a regular month. The results indicate that Ramadan fasting can lead to a significant decrease in athletic performance capacities. The decrease in performance does not necessarily relate to changes in caloric intake and sleeping hours during the fast.