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. Author manuscript; available in PMC: 2008 Apr 30.
Published in final edited form as: Neurobiol Aging. 2006 Apr 18;28(5):799–807. doi: 10.1016/j.neurobiolaging.2006.03.005

Figure 3.

Figure 3

Plasma melatonin data from subject 19G7, a 65 year old man who was exposed to a 3,527 lux light stimulus. Upper panel: plasma melatonin data from the initial circadian phase estimation procedure (CR1); middle panel: plasma melatonin data from the intervention day, with the 6.5-h experimental light exposure indicated by the open box; lower panel: plasma melatonin data from the final circadian phase estimation procedure (CR2) shown in the solid symbols, with data from CR1 replotted from above in the open symbols. During CR1, the fitted peak of the melatonin secretion (MELmax) occurred at 03:45, 3.5 h before habitual wake time. During CR2 MELmax occurred at 06:30, a 3.5 h phase delay. Melatonin was suppressed by 78% during the 6.5-h 3,527 lux light stimulus.