How does diurnal intermittent fasting impact sleep, daytime sleepiness, and markers of the biological clock? Current insights

Abstract

Mealtimes and feeding schedules may interfere with the circadian system and impact sleep. The practice of intermittent fasting (IF) in its different formats is increasing worldwide. However, most studies addressing the effect of IF on circadian rhythms, daytime sleepiness, and sleep architecture have been conducted during diurnal IF for Ramadan. In this article, we analyze the effect of diurnal IF on the circadian clock, sleep, and daytime sleepiness. In free-living, unconstrained environments that do not control for lifestyle changes such as sleep/wake schedules, sleep duration, and light exposure, studies have demonstrated sudden and significant delays in bedtime and wake time during diurnal intermittent fasting for Ramadan. However, subsequent studies that accounted for lifestyle factors and sleep/wake patterns have reported no changes in markers of the biological clock, daytime sleepiness, or sleep parameters. Nevertheless, several researchers have demonstrated a reduction in the proportion of rapid eye movement stage sleep as the significant alteration in sleep architecture during fasting.

Recent Evidence on the Impact of Ramadan Diurnal Intermittent Fasting, Mealtime, and Circadian Rhythm on Cardiometabolic Risk: A Review

“…Furthermore, some of the proposed experimental fasting protocols, such as the alternate-day fasting protocol are not practical due to accompanying severe hunger (41). As there are major differences between Ramadan diurnal IF and other forms of experimental IF, in this article, we restricted the discussion to Ramadan diurnal IF (42).…”

“…Theoretically, restricting feeding to a limited time of the 24-h day is expected to result in reduced energy intake, and this is the essence of diurnal IF during Ramadan (42). Ideally, in Ramadan, fast performers are expected to eat two main meals, breakfast at sunset and a pre-dawn (suhur) meal ∼30 min before dawn, and to get a good night sleep.…”

“…This practice is expected to result in weight loss and improved physiological parameters that are related to increased weight. However, in real life, this does not always occur as many lifestyle and cultural factors interact with the IF practice during Ramadan (Figure 1) (4,42). In other words, Ramadan fasting can be considered as a TRF schedule without intentional restrictions on energy consumption, where two large meals are administered; one at sunset and the other in the early morning before dawn, and adequate sleep at night (44).…”

The Effects of Diurnal Intermittent Fasting On Proinflammatory Cytokine, Oxidative Stress and Heat Shock Protein 70 Levels

“…International Journal of Scientific and Technological Research www.iiste.org ISSN 2422-8702 (Online), DOI: 10.7176/JSTR/6-03-41 Special Issue of Health Sciences, Vol.6, No.3, 2020 1. Introduction Diurnal intermittent fasting (DIF) is practiced by hundreds of millions of Muslims during the month of Ramadan (Almeneessier & Bahammam, 2018). The effects of DIF on human health have attracted the attention of investigators in the past few years.…”

“…The effects of DIF on human health have attracted the attention of investigators in the past few years. DIF is not similar to caloric restriction (CR), in which caloric intake is reduced for long periods, but meal frequency is preserved (Almeneessier & Bahammam, 2018). During Ramadan DIF, fast performers abstain from food, drinks, and smoking from dawn to sunset for a period of one month.…”