Abstract Mkid 122

We assessed the effect of Islamic fasting and its attendant changes in lifestyle on total sleep time, sleep habits, daytime sleepiness, and eating habits in a group of young healthy subjects during the first 3 weeks of Ramadan. Study participants were healthy Muslim medical students, male and female, who fast for Ramadan. A self-administered questionnaire was designed and given four times: 1) 1 week before Ramadan (baseline, BL), and 2) the first week (R1), 3) second week (R2), and 4) third week of Ramadan (R3) to assess sleep habits, daytime sleepiness and functioning, and eating habits. During weekdays, participants were asked to monitor their sleep habits and other parameters described in the questionnaire, and then to complete the questionnaire on the last weekday of each week, according to the timetable set in the study design. Complete information was available for 56 participants (25 females and 31 males). Bedtime was delayed significantly during Ramadan as compared to BL. There was also a significant delay in wake-up time during Ramadan as compared to BL. Total sleep time at night (TST) dropped slightly during Ramadan as compared to BL, but this drop did not reach statistical significance. The percentage of students who napped during the daytime, 52% before Ramadan, increased significantly to 73% in R1. However, there was no significant difference in TST + naps between BL (7.25±2 hours) and the first 3 weeks of Ramadan. Despite the insignificant change in TST, Epworth Sleepiness Scale (ESS) scores were significantly higher during Ramadan. The time of the main meal changed as well, reflecting the fact that the subjects were fasting during the daytime. The present study revealed several modifications in circadian rhythm, social activity, and eating habits of fasting individuals during the month of Ramadan. These changes affected daytime functioning and resulted in increased sleepiness despite the insignificant change in TST. Further studies are needed to objectively assess daytime sleepiness, sleep-wake schedule, and the circadian pattern of melatonin secretion in those who fast for Ramadan.