Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Treatment-induced changes of the nocturnal melatonin rhythm in young (A, B) and older (C, D) adults. Subjects were exposed to 4 hours of dim control (A, C) or bright (B, D) light on the treatment night. Melatonin levels, measured throughout the night prior to (dashed) and following (solid line) the treatment night, are plotted as a percent of maximum.
