First author John Axelsson of the Osher Center for Integrative Medicine and the Karolinska Institutet in Sweden and colleagues say the study involved 23 healthy, sleep deprived adults -- ages 18-31 -- who were photographed and 65 untrained observers -- ages 18-61 -- who rated the photographs.
The study, published in the British Medical Journal, found sleep deprived people were rated as less healthy, more tired and less attractive than after a normal night's sleep.
"Our findings show that sleep deprived people appear less healthy, less attractive, and more tired compared with when they are well rested," the researchers say in a statement. "This suggests that humans are sensitive to sleep related facial cues, with potential implications for social and clinical judgments and behavior. Studies are warranted for understanding how these effects may affect clinical decision making and can add knowledge with direct implications in a medical context."
To date, the concept of beauty sleep has lacked scientific support, but the biological importance of sleep may have favored a sensitivity to perceive sleep related cues in others, the researchers add.