Observant Muslims substantially alter their normal routines, including daytime fasting and day-night activity patterns during the month of Ramadan. It is unknown whether observing the religious practices of Ramadan impacts negatively on daytime somnolence, a factor known to impair learning. A cross-sectional survey measuring self-reported sleep time and the Epworth Sleepiness Scale of observant Muslim medical students before, during, and after Ramadan. There was no significant variation in sleep score pre-Ramadan (10.04 +/- 3.47), during Ramadan (10.46 +/- 3.57)m and post Ramadan(9.73 +/- 3.33), F(2,355) = 1.278, p = .280. Night sleep hours were significantly longer both before (6.22 +/- 1.45) and after (6.22 +/- 1.59) than during Ramadan (5.22 +/- 1.85), F(2,366) = 15.289, p < .001. Daytime sleep hours pre-Ramadan (1.05 +/- 1.36) and post Ramadan (0.70 +/- 1.21) were significantly shorter than during Ramadan (1.48 +/- 1.46; pre: z = 2.654, p = .08; z = -4.940, p < .001). Students successfully adapt and avoid a rise in daytime somnolence by increasing daytime sleep hours during Ramadan.