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. Author manuscript; available in PMC: 2007 Dec 1.
Published in final edited form as: Neurobiol Aging. 2005 Nov 23;27(12):1870–1879. doi: 10.1016/j.neurobiolaging.2005.10.011

Figure 4.

Figure 4

Treatment-induced phase delays of the melatonin midpoint. 4 hours exposure to bright light (open bars) delayed the melatonin rhythm in both the young (p < 0.001, n = 16) and older (p < 0.001, n = 14) groups. The melatonin midpoint did not significantly change after awakening for 4 hours under dim light (n = 7 - 8). Phase delays following bright light exposure were significantly greater than following the dim control condition (p < 0.001). The magnitude of phase delays were not significantly different between the young and older adults.