Daytime sleepiness during Ramadan intermittent fasting: polysomnographic and quantitative waking EEG study

Abstract

SUMMAR Y During the lunar month of Ramadan, Muslims abstain from eating, drinking and smoking from sunrise to sunset. We reported previously that Ramadan provokes a shortening in nocturnal total sleep time by 40 min, an increase in sleep latency, and a decrease in slow-wave sleep (SWS) and rapid eye movement (REM) sleep duration during Ramadan. During the same study, the effects of Ramadan intermittent fasting on daytime sleepiness were also investigated in eight healthy young male subjects using a quantitative waking electroencephalograph (EEG) analysis following the multiple sleep latency test (MSLT) procedure. This procedure was combined with subjective alertness and mood ratings and was conducted during four successive experimental sessions: (1) baseline (BL) 15 days before Ramadan, (2) beginning of Ramadan (R11) on the 11th day of Ramadan, (3) end of Ramadan (R25) on the 25th day of Ramadan, (4) recovery 2 weeks after Ramadan (AR). During each session, four 20-min nap opportunities (MSLTs) were given at 10:00, 12:00, 14:00 and 16:00 h and were preceded by rectal temperature readings. Nocturnal sleep was recorded before each daytime session. Subjective daytime alertness did not change in R25 but decreased in R11 at 12:00 h, and subjective mood decreased at 16:00 h, both in R11 and R25. During the MSLT, mean sleep latency decreased by an average of 2 min in R11 (especially at 10:00 and 16:00 h) and 6 min in R25 (especially at 10:00 and 12:00 h) compared with BL. There was an increase in the daily mean of waking EEG absolute power in the theta (5.5-8.5 Hz) frequency band. Significant correlations were found between sleep latency during the MSLT and the waking EEG absolute power of the fast alpha (10.5-12.5 Hz), sigma (11.5-15.5 Hz) and beta (12.5-30 Hz) frequency bands. Sleep latency was also related to rectal temperature. In conclusion, Ramadan diurnal fasting induced an increase in subjective and objective daytime sleepiness associated with changes in diurnal rectal temperature.

Influence of Ramadan Observance on Sleep Pattern and Wakefulness at Work among Medical Trainer in Tunisia

“…Metabolic changes during the intermittent fasting have been also ruled out as possible factor for increase in subjective and objective sleepiness. Actually Ramadan diurnal fasting lead to decrease in the resting rate and energy expenditure, which in return bring about diurnal rectal temperature decrease as was observed by Roky [18]. It also induces increased cerebral theta activity [22].…”

“…Bahammam noted that the percentage of medical students who reported falling asleep in class increased from 15% at baseline to 36% during the first week of Ramadan [1]. The study of Roky [18] including 8 young Muslims showed an increase in daytime sleepiness, especially at 10:00 and 12:00 am at the end of Ramadan, and a decrease in daytime body temperature during Ramadan. Objective measure of alertness by the MSLT confirmed these results.…”

Physiological and Chronobiological Changes during Ramadan Intermittent Fasting

“…Objective measure of alertness by the multiple sleep latency test confi rmed these results. Sleep latency, which is inversely proportional to sleepiness, increased during the daytime, particularly at 10: 00, 12: 00 and 16: 00 h [72] . Psychomotor performances, such as critical fl icker fusion [73] and choice reaction time [71], were especially impaired by Ramadan fasting in the fi rst week of this month.…”

Influence of Ramadan on Neuroperformance in Healthy Workers

“…Objective sleepiness measured by EEG seems slightly increased between 10:00 and 12:00 h. At other times of the day there were no important differences with results outside the Ramadan (Roky et al 2003).…”