It's time to catch more shut-eye. A new study shows that people who get more sleep appear more attractive. The Karolinska Institute in Sweden took photographs of 23 different subjects between 18 to 31 years of age. The first photo was taken after the subject received a normal eight hours of sleep. Another photo was taken after the subject stayed awake for 31 hours and was given only five hours of rest. The subjects didn't wear any makeup and were photographed in a brightly lit room. Then 65 objective observers were asked to compare the photographs and say which photo was more attractive. Overall, the observers found the photos of the sleep-deprived subjects to be uglier than the well-rested subjects. The research was published in the BMJ, a British medical journal, and reports that the recent finding show, "that humans are sensitive to sleep-related facial cues, with potential implications for social and clinical judgments and behavior."