Don Quijote de la Mancha y la descripción del sueño bifásico en la literatura española / Don Quixote de la Mancha and the description of biphasic sleep in Spanish literature

Introducción: El sueño bifásico o segmentado es el hábito de dormir un primer y un segundo sueño separados por una vigilia. El historiador Ekirch describe que así se dormía en los tiempos preindustriales antes de la potente iluminación artificial. Se basó en textos en diferentes idiomas, desde la Antigüedad hasta el siglo xx, pero llama la atención la ausencia de fuentes en español. Objetivo: Se revisó la literatura española en busca de referencias al sueño bifásico usando como palabras clave ‘primer sueño’ y ‘a los primeros gallos’. Desarrollo: En la segunda parte de Don Quijote de la Mancha (capítulo 68), Cervantes describe el sueño bifásico con notable acierto, correlacionando los biotipos de Quijote y Sancho con sus temperamentos y hábitos de sueño y alimentarios. Curiosamente, Ekirch cita el capítulo, pero no el sueño bifásico. En esta revisión reproduzco 11 textos en español (siglos xiii a xix), mayormente obras clásicas, que lo refieren, disponiendo sus fases en coincidencia con las horas en que se dividía la noche en la era preindustrial: 20:00-21:00 a 00:00, primer sueño; 00:00 a 03:00, vigilia; 03:00 a 06:00, segundo sueño. La Celestina aporta datos significativos. Estudios recientes probaron que este hábito es fisiológico y se adapta al estilo de vida que lo requiere. Conclusiones: Se identifican y citan por primera vez referencias al sueño bifásico en la literatura española, confirmando la hipótesis de Ekirch. El Quijote lo describe con mayor amplitud y agudeza.(AU)

Introduction: Biphasic or segmented sleep is the habit of sleeping a first and a second sleep separated by a watching. The historian A Ekirch found that this was how people slept in pre-industrial times before the powerful artificial lighting. He is based on texts in different languages, from Antiquity to the 20th century, but the absence of sources in Spanish is striking. Aim: Review the Spanish literature searching references of the biphasic sleep using the keywords ‘first sleep’ and ‘at the first cockcrow’. Development: In the Second Part of Don Quixote de la Mancha (Chapter 68), Cervantes describes biphasic sleep with remarkable success, correlating the biotypes of Quixote and Sancho with their temperaments and sleeping and eating habits. Strangely, Ekirch cites the chapter, but not biphasic sleep. In this review I reproduce eleven texts in Spanish (13th to 19th centuries), mostly classical works, which refer to it by arranging its phases in a way that coincides with the hours in which the night was divided in the pre-industrial era: 20:00-21:00 to 00:00, first sleep, 00:00 to 03:00, wakefulness; 03:00 to 06:00, second sleep. La Celestina provides significant data too. Recent studies proved that this habit is physiological, and it adapts to the lifestyle that requires it. Conclusions: References to biphasic sleep in Spanish literature are identified and cited for the first time, confirming Ekirch’s hypothesis. In Don Quixote, Cervantes describes it with great breadth and sharpness.

The submariners' sleep study: a field investigation of sleep and circadian hormones during a 67-day submarine mission with a strict 6-h-on/6-h-off watch routine.

The submarine working and living environment is an isolated, confined, and extreme (ICE) environment where a continuous on-watch is required to fulfill the tactical objectives. The current study examined whether a physiological and behavioral adjustment to an operational watch standing scheme occurred in terms of hormonal secretion (i.e., melatonin and cortisol) and sleep during a 67-day undersea mission. The crew followed a strict scheme of watch-on blocks at 0:00-06:00 h and at 12:00-18:00 h (group 1, diurnal sleep group) or watch-on blocks at 06:00-12:00 h and 18:00-24:00 h (group 2, nocturnal sleep group). We sampled saliva during the operational blocks over a 24-h period at day 55 of the mission and collected sleep actigraphy data during the entire mission in 10 participants. Sleep showed a biphasic split pattern with significantly unequal distributions of total sleep time (TST) and sleep efficiency (SE) between the two sleeping blocks, i.e., one long and one short sleep bout. Melatonin secretion showed no adjustment at the end of the mission to the watch standing blocks, following an endogenous circadian rhythm independent from the social zeitgebers with indications of a phase shift. Cortisol secretion however matched the biphasic work-sleep shift routine. Human physiology does not fully obey operational needs and there are differences in adjustment between melatonin and cortisol. A watch standing schedule that provides a balance between physiology and operationality still needs to be established. The potential adaptation effects of bright light therapy and melatonin supplementation should be investigated in future research.NEW & NOTEWORTHY The current study has a unique character due to the field context in which the data were collected. Data on long-term submarine missions are scarce and valuable in terms of operational and ecological validity. Moreover, the results are important both from a scientific and operational point of view, showing that human physiology does not fully obey operational needs and that there are differences in adjustment dependent from the type of circadian hormone.

(Pre)Modern sleep. New evidence from the Antwerp criminal court (1715-1795).

Lately, experts have turned to historical evidence to uncover the default mode of our sleep pattern. Even though there are some notable exceptions, most historians use a qualitative methodology based on scattered evidence in diaries, letters, novels, medical treatise and other literary sources. To provide fresh perspective in the debate, the present article develops a more quantitative approach. Drawing fresh evidence from early modern criminal records - viz the eyewitness reports of the Hoge Vierschaer or the local criminal court in Antwerp - we are able to debunk some classic stereotypes about premodern sleep patterns. Data reveal that most 18th -century Antwerpers slept fewer hours than we would expect, slumbered in a monophasic way and rarely if ever took a nap during the day. Moreover, the start and end of sleep were less attuned to the solar cycle than we would imagine. Last but not least, the pattern also shows some fascinating weekly and seasonal variations.