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.

Time-restricted feeding and cognitive function in sedentary and physically active elderly individuals: Ramadan diurnal intermittent fasting as a model.

Objectives: This study aimed to investigate the effects of Ramadan diurnal intermittent fasting (RDIF) on cognitive performance, sleep quality, daytime sleepiness, and insomnia in physically active and sedentary elderly individuals. Methods: A total of 58 participants (62.93 ± 3.99 years) were assigned to one of the following two groups: a sedentary group (control group) who observed Ramadan (n = 32) and a physically active group (n = 26) who continued to train while observing Ramadan. Participants were assessed 2 weeks before Ramadan and during the fourth week of Ramadan. On each occasion, participants completed a digital assessment of their cognitive performance and responded to the Pittsburgh sleep quality index (PSQI), the insomnia severity index (ISI) and the Epworth sleepiness scale (ESS) questionnaires to assess sleep parameters. Results: Compared to before Ramadan, performance in executive function (p = 0.035), attention (p = 0.005), inhibition (p = 0.02), associative memory (p = 0.041), and recognition memory (p = 0.025) increased significantly during Ramadan in the physically active group. For the sedentary group, associative learning performance decreased (p = 0.041), whilst performances in the remaining domains remained unchanged during Ramadan. Global PSQI, ISI, and ESS scores indicated both groups suffered from poor sleep quality and excessive daytime sleepiness, with significantly higher negative effects of RDIF observed in the sedentary group. Conclusion: Older adults who continue to train at least three times per week during Ramadan may improve their cognitive performance, despite the impairment of sleep quality. Future studies in older adults during Ramadan including objective measures of sleep (e.g., polysomnography, actigraphy) and brain function (e.g., functional magnetic resonance imaging) are warranted.

Observing Ramadan and sleep-wake patterns in athletes: a systematic review, meta-analysis and meta-regression.

OBJECTIVE: To evaluate the effect of observing Ramadan on athletes' sleep patterns. DESIGN: Systematic review and meta-analysis. DATA SOURCES: The entire content of PubMed/MEDLINE and Web of Science. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Single-group, prepost and cross-over design studies conducted in athletes aged ≥18 years, training at least twice a week and published in English before 12 July 2018 were included. Studies assessing sleep quantity, quality, daytime sleepiness and/or daily naps based on objective or subjective methods were deemed eligible. STUDY APPRAISAL: The methodological quality was assessed using 'QualSyst'. RESULTS: Of 13 selected articles, 7 were of strong quality, 3 were moderate and 3 were weak. 11 studies evaluated total sleep time (TST); this decreased during Ramadan in 4 studies, increased in 1 and remained unchanged in 6. Pooled TST findings indicated a moderate effect size (- 0.97, SE=0.37, 95% CI -1.69 to -0.25, t=-2.64, p=0.01) with significant heterogeneity but no publication bias. Meta-regressions showed no effects of study year, age, sample size, type of sport or competition level, but there were effects of country (with France and Tunisia being the most affected countries and Turkey the least affected, Q=32.14, p<0.0001) and study design (Q=7.74, p=0.02). Four studies measured self-reported sleep quality and it decreased in three studies. One study of sleep architecture reported more frequent waking and more light sleep during Ramadan. Daily nap duration was increased in two studies, but daytime sleepiness remained unchanged in four studies. CONCLUSION: When athletes continue to train at least two times/week while observing Ramadan, TST is decreased compared with athletes' baseline levels.

Practical recommendations to improve sleep during Ramadan observance in healthy practitioners of physical activity.

BACKGROUND: During the month of Ramadan, many Muslims continue to exercise and/or to compete in sporting events. However, the combination of Ramadan observance (RO) and physical activity (PA) is likely to be associated with disrupted sleep-wake patterns. OBJECTIVES: to (i) evaluate the effects of RO on sleep patterns in practitioners of PA and (ii) provide some evidence-based practical recommendations to improve an active individual's sleep patterns during RO. METHODS: The entire content of two databases, PubMed/MEDLINE and Web of Science was searched for relevant articles through March, 25 2019. All accepted articles concerned healthy practitioners of PA and have assessed sleep quantity and/or quality and/or daily naps, whether based on objective or subjective methods. RESULTS: Thirteen studies evaluated total sleep time (TST) of active individuals in relation to RO; TST decreased in five studies, increased in one and remained unchanged in seven studies. Sleep quality was self-estimated in five studies, with three noting a decreased quality of sleep and two reporting no change. The duration of daily naps was increased in two studies. Conclusions and practical recommendations: Continuation of PA during RO did not decrease TST. However, no firm conclusions can be drawn regarding sleep quality/characteristic and daily naps durations. Sleep quantity and quality should be evaluated in order to counteract sleep disturbances. Physically active individuals should avoid large late night meal, and if possible take 20- to 30- minute daytime naps. A 10- minute shower at ∼40°C and a self-administered 6-min mindfulness induction video may be helpful immediately before bedtime. Tryptophan (1g/day) or melatonin (5- 8mg) supplements may also improve sleep characteristics.

Effects of Ramadan fasting on athletes' hematological indices: a systematic review.

OBJECTIVE: To evaluate the effects of Ramadan fasting on hematological data in athletes through a systematic appraisal of the literature. DESIGN: Systematic review Data sources: The entire content of two databases, PubMed/MEDLINE and Web of Science Eligibility criteria for selecting studies: Ramadanrelated measurements of any hematological indices in athletes were considered. Both single-group pre-post with and without a control group studies conducted in athletes and published in English language before December 31, 2018 were included. Study appraisal: The methodological quality of the studies identified was assessed using 'QualSyst'. RESULTS: Of nine selected articles, eight were of moderate quality and only one was of strong quality. The main problem to date has been a lack of appropriate controls. Compared to before Ramadan, hematocrit and hemoglobin values increased in three studies, decreased in one study and did not change in one study during Ramadan fasting. Another study reported increased hematocrit and a puzzling decrease of hemoglobin during as compared to before Ramadan fasting. In most studies, blood platelet counts and the limited number of immune function used to date remainedunchanged. CONCLUSIONS: All reported changes in hematological indices remained within the normal reference range of the laboratory. Therefore, regular training can continue safely during Ramadan fasting from a hematological view point.