Short wavelength light administered just prior to waking: A pilot study

Michael A. Grandner, Daniel F. Kripke, Jeffrey Elliott, Roger Cole

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Bright light in the blue-green range, administered in the early morning hours (prior to waking) may be particularly effective in shifting circadian rhythms and may increase gonadotropin production. Accordingly, we tested the feasibility and utility of a mask that emits bright blue/green light (compared to a similar mask that emitted a dim red light) towards the end of sleep in a randomized, placebo-controlled pilot study. The study included a three-day baseline period, immediately followed by a 12-day intervention period. Subjects were 30 healthy young men with minimal-mild depression. The bright light masks were well-tolerated and demonstrated adequate safety and feasibility. Following the intervention, those who wore the bright light mask demonstrated altered sleep timing suggestive of an earlier sleep period, and excreted a slight increase in follicle-stimulating hormone (FSH). Overall, light masks may prove useful in future studies of bright light therapy.

Original languageEnglish (US)
Pages (from-to)13-32
Number of pages20
JournalBiological Rhythm Research
Issue number1
StatePublished - Jan 1 2013


  • Circadian rhythms
  • Depression
  • Hormones
  • Light
  • Sleep

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Physiology (medical)


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