This Article Full Text Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints, Permissions and Rights Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Revell, V. L. Articles by Eastman, C. I. Search for Related Content PubMed PubMed Citation Articles by Revell, V. L. Articles by Eastman, C. I. Related Collections Neuroendocrinology and Pituitary

Advancing Human Circadian Rhythms with Afternoon Melatonin and Morning Intermittent Bright Light

Biological Rhythms Research Laboratory, Rush University Medical Center, Chicago, Illinois 60612

Address all correspondence and requests for reprints to: Charmane I. Eastman, Ph.D., Biological Rhythms Research Lab, Rush University Medical Center, 1645 West Jackson Boulevard, Suite 425, Chicago, Illinois 60612. E-mail: ceastman{at}rush.edu.

Context: Both light and melatonin can be used to phase shift the human circadian clock, but the phase-advancing effect of the combination has not been extensively investigated.

Objective: The objective of the study was to determine whether phase advances induced by morning intermittent bright light and a gradually advancing sleep schedule could be increased with afternoon melatonin.

Participants: Healthy adults (25 males, 19 females, between the ages of 19 and 45 yr) participated in the study.

Design: There were 3 d of a gradually advancing sleep/dark period (wake time 1 h earlier each morning), bright light on awakening [four 30-min bright-light pulses (5000 lux) alternating with 30 min room light < 60 lux] and afternoon melatonin, either 0.5 or 3.0 mg melatonin timed to induce maximal phase advances, or matching placebo. The dim light melatonin onset was measured before and after the treatment to determine the phase advance.

Results: There were significantly larger phase advances with 0.5 mg (2.5 h, n = 16) and 3.0 mg melatonin (2.6 h, n = 13), compared with placebo (1.7 h, n = 15), but there was no difference between the two melatonin doses. Subjects did not experience jet lag-type symptoms during the 3-d treatment

Conclusions: Afternoon melatonin, morning intermittent bright light, and a gradually advancing sleep schedule advanced circadian rhythms almost 1 h/d and thus produced very little circadian misalignment. This treatment could be used in any situation in which people need to phase advance their circadian clock, such as before eastward jet travel or for delayed sleep phase syndrome.

This article has been cited by other articles:

				P Gringras When to use drugs to help sleep Arch. Dis. Child., November 1, 2008; 93(11): 976 - 981. [Abstract] [Full Text] [PDF]

				H. J. Burgess, V. L. Revell, and C. I. Eastman A three pulse phase response curve to three milligrams of melatonin in humans J. Physiol., January 15, 2008; 586(2): 639 - 647. [Abstract] [Full Text] [PDF]