Caffeine and Sleep (IMAGE) University of Colorado at Boulder Caption A new study led by CU-Boulder shows for the first time that caffeine in the evening can delay our our circadian clocks that tell us when ready for to sleep and for awakening. Credit Kenneth Moyle Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.