Perspective: Casting light on sleep deficiency

Division of Sleep Medicine, Harvard Medical School, and Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital, in Boston, Massachusetts.
Nature (Impact Factor: 41.46). 05/2013; 497(7450):S13. DOI: 10.1038/497S13a
Source: PubMed


The use of electric lights at night is disrupting the sleep of more and
more people, says Charles Czeisler.

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    • "By this route, information about the amount of light falling on the retina regulates the operation of the SCN, controlling circadian rhythms, including sleep and waking. " [L]ight affects our circadian rhythms more powerfully than any drug " (Czeisler, 2013, S13). The regularly repeating daily exposure to light and dark results in a stable sleepewake cycle, which is essential for mental and physical health (e.g., Alvarez & Ayas, 2004; Alvaro, Roberts, & Harris, 2013). "
    Journal of Environmental Psychology 01/2014; · 2.40 Impact Factor
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    • "It has also been proposed that the use of electricity for light artificially shortens human exposure to nocturnal darkness, extends the active period, and leads to a consolidated bedtime and shorter sleep duration than would be observed in a natural light-dark cycle (Wehr, 1999). The use of electricity can disrupt circadian rhythms, and this could lead to increased sleep deficiency (Czeisler, 2013). Thus, individuals living in areas with limited or no access to electricity may exhibit different sleep-wake patterns than have been observed in industrialized countries. "
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    ABSTRACT: Sleep comprises one-third of one's life, yet little is known about sleep in developing countries. Furthermore, many studies in industrialized countries have reported that sleep duration and quality decline with aging, but whether this association persists globally is unknown. This study's objectives were to characterize sleep in a community without electricity in Haiti and to examine associations between measures of sleep and age. Fifty-eight Haiti residents (50% women) in four age groups, 18-30, 31-50, 51-64, and ≥65 years participated. Three days of wrist actigraphy were used to estimate sleep patterns. Mean (standard deviation) values of sleep measures were: 20:57 (0:40) for sleep onset, 4:54 (0:43) for sleep end, 9.3 (1.2) h for time in bed, 7.0 (1.0) h for sleep duration, 54 (24) min awake after sleep onset, and 88.7 (5.4)% for sleep maintenance (percentage of sleep period actually spent sleeping). There were no significant differences in the sleep measures between men and women. Regression analyses adjusting for sex, household size, and number of people sleeping in the same room indicated that only sleep fragmentation differed by age group. Specifically, mean fragmentation was higher in the youngest age group than all other age groups, which did not differ from one another. Average time in bed in this Haitian sample was greater than previously reported for industrialized countries like the United States (9.3 versus. 7-8 h);, however, actual sleep duration averaged only 7 h. No age-related decline in sleep duration or quality was observed in Haiti. Am. J. Hum. Biol., 2013. © 2013 Wiley Periodicals, Inc.
    American Journal of Human Biology 01/2014; 26(1). DOI:10.1002/ajhb.22481 · 1.70 Impact Factor
  • Journal of clinical sleep medicine: JCSM: official publication of the American Academy of Sleep Medicine 08/2013; 9(8):739-40. DOI:10.5664/jcsm.2906 · 3.05 Impact Factor
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