Beauty sleep is a real thing. People who miss out on sleep do appear less attractive to others. They are rated by strangers as less healthy and approachable when they have tired faces.
The Karolinska Institute researchers asked 25 students, some male and some female, to get a two good nights’ sleep in a row. This was monitored with a kit that recorded their night-time movements. They were then asked to restrict themselves to just four hours sleep for two consecutive evenings
Make-up free photos were then taken of both scenarios. The researchers next asked 122 strangers to look at the pictures and rate them on attractiveness, health, sleepiness and trustworthiness.
The strangers said they would be less likely to socialize with the sleepy participants because they looked unhealthy. "An unhealthy-looking face, whether due to sleep deprivation or otherwise, might activate disease-avoiding mechanisms in others," say the researchers.
Source article: http://iservice.ltn.com.tw/Service/english/english.php?engno=1108244&day=2017-06-06