A new study finds that around the full moon humans get less shut-eye and their slumber is not as deep, even if sleep is restricted to windowless rooms free of environmental and time-based cues—such as those found in a sleep lab. The findings … suggest that restful sleep takes a hit during a full moon as well as a few days before and after the phase. Still, no one has any idea why that would occur or what biological mechanism could be at work.