Light Treatment for Sleep Disorders: Consensus Report: VI. Shift Work

Charmane I. Eastman, Ziad Boulos, Michael Terman, Scott S. Campbell, Derk Jan Dijk, Alfred J. Lewy

Research output: Contribution to journalArticlepeer-review

129 Scopus citations


The unhealthy symptoms and many deleterious consequences of shift work can be explained by a mismatch between the work-sleep schedule and the internal circadian rhythms. This mismatch occurs because the 24-h zeitgebers, such as the natural light-dark cycle, keep the circadian rhythms from phase shifting to align with the night-work, day-sleep schedule. This is a review of studies in which the sleep schedule is shifted several hours, as in shift work, and bright light is used to try to phase shift circadian rhythms. Phase shifts can be produced in laboratory studies, when subjects are kept indoors, and faster phase shifting occurs with appropriately timed bright light than with ordinary indoor (dim) light. Bright light field studies, in which subjects live at home, show that the use of artificial nocturnal bright light combined with enforced daytime dark (sleep) periods can phase shift circadian rhythms despite exposure to the conflicting 24-h zeitgebers. So far, the only studies on the use of bright light for real shift workers have been conducted at National Aeronautics and Space Administration (NASA). In general, the bright light studies support the idea that the control of light and dark can be used to overcome many of the problems of shift work. However, despite ongoing practical applications (such as at NASA), much basic research is still needed.

Original languageEnglish (US)
Pages (from-to)157-164
Number of pages8
JournalJournal of biological rhythms
Issue number2
StatePublished - Jun 1995
Externally publishedYes


  • bright light
  • circadian rhythms
  • shift work

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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