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

Abstract

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.

Keywords:

• sleep
• light
• hormones
• circadian rhythms
• depression

Acknowledgment

This research was supported by the National Institute of Mental Health, MH68545. This work completed as part of the dissertation project entitled “Sleep, Mood and Circadian Responses to Bright Green Light During Sleep” by Dr. Grandner, who wishes to acknowledge the guidance of his committee, including Dr. Kripke (Chair), Dr. Sonia Ancoli-Israel and Dr. Sean P. A. Drummond from the University of California, San Diego and Dr. Linda Gallo and Dr. Claire Murphy from San Diego State University. Dr. Cole, at one time, had a patent on the light masks used for this study, but this patent has expired and therefore he retains no financial interest in light masks.