For sleep-and-monks-and-nuns enthusiasts

Rare is the study that focus on how monks and nuns sleep. One is:

Ring the Bell for Matins: Circadian Adaptation to Split Sleep by Cloistered Monks and Nuns,” Isabelle Arnulf [pictured here], Agnès Brion, Michel Pottier and Jean-Louis Golmard, Chronobiology International, Dec., 2011, Vol. 28, No. 10 , pp. 930-41. (Thanks to investigator Yvette Bain for bringing this to our attention.) The authors, at Pitié-Salpêtrière Hospital and other institutions in Paris, explain:

“Cloistered monks and nuns adhere to a 10-century-old strict schedule with a common zeitgeber of a night split by a 2- to 3-h-long Office (Matins). The authors evaluated how the circadian core body temperature rhythm and sleep adapt in cloistered monks and nuns in two monasteries. Five monks and five nuns following the split-sleep night schedule for 5 to 46 yrs without interruption and 10 controls underwent interviews, sleep scales, and physical examination and produced a week-long sleep diary and actigraphy, plus 48-h recordings of core body temperature….

“In contrast to their daytime silence, they experienced conversations (and occasionally prayers) in dreams. The biphasic temperature profile in monks and nuns suggests the human clock adapts to and even anticipates nocturnal awakenings. It resembles the biphasic sleep and rhythm of healthy volunteers transferred to a short (10-h) photoperiod and provides a living glance into the sleep pattern of medieval time.”