A Swedish study is backing the concept with some science.
Researchers say people deprived of sleep for long periods actually appear unhealthy compared to those who are well rested.
Volunteers were photographed after eight hours of sleep and again after being kept awake for 31 hours. Observers scored the sleep deprived participants as less healthy and less attractive.
The authors say the results may be useful in a medical setting, helping doctors pick up on signs of ill health in their patients.
There's more on the study in the British Medical Journal.
