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Evening melatonin and bright light administration induce additive phase shifts in dim light melatonin onset
Author(s) -
WirzJustice Anna,
Kräuchi Kurt,
Cajochen Christian,
Danilenko Konstantin V.,
Renz Claudia,
Weber Jakob M.
Publication year - 2004
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/j.1600-079x.2004.00117.x
Subject(s) - melatonin , zeitgeber , circadian rhythm , evening , endocrinology , medicine , phase response curve , pineal gland , photoperiodism , morning , circadian clock , physics , astronomy
In healthy young men, administration of a single light pulse (5000 lux for 3 hr) or a single melatonin pill (5 mg) at 20:40 hr under controlled constant routine conditions of <10 lux, yielded a phase delay and a phase advance, respectively, in the circadian marker of dim light melatonin onset 24 hr later. Phase shifts after combining the two interventions were additive. Melatonin suppression is not necessary for a phase shift by light, and melatonin is not a ‘weak’ Zeitgeber relative to bright light when ambient lighting is strictly controlled.