Teens' Sleep is Physiologically Different (IMAGE) MediaSource Caption Melatonin, the hormone that helps regulate our sleep, shifts by about two hours during puberty -- making it harder for teens to fall asleep early. Credit National Jewish Health 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.