Caffeine at night delays human circadian clock
www.colorado.edu
It’s no secret that slugging down caffeinated drinks in the evening can disrupt sleep. But a new study led by the University of Colorado Boulder and the Medical Research Council’s Laboratory of Molecular Biology in Cambridge, England shows for the first time that evening caffeine delays the internal circadian clock that tells us when to get ready for sleep and when to prepare to wake up.

Caffeine + bright light (105 min) isn’t significantly more effective than bright light alone (85 mins) or caffeine alone (85 mins)