The findings underscore the link between sleep, attractiveness and a healthy appearance, suggesting that beauty sleep really is a thing.
The experiment The researchers asked 25 university students, some male and some female, to be the guinea pigs in their sleep experiment.
Participants were asked to get a good night's sleep for two consecutive nights and restrict it to four hours a night a week later, for another two nights in a row.
122 volunteers (65 women, 57 men) aged between 18 to 65 were then asked how much they would like to socialize with the person in the photo.More news: China's Xi appeals to foreign leaders for freer trade
Not only were participants rated as less attractive and healthy following sleep restriction than when they were well rested, but the raters also reported a reduced willingness to socialize with adults who looked sleep-deprived. "An unhealthy-looking face, whether due to sleep deprivation or otherwise, might activate disease-avoiding mechanisms in others".
"Sleep deprivation is associated with a wide variety of physiological changes, such as impaired immune function, reduced cardiovascular health, and even impaired glucose metabolism", she says, which is why people who are sleep deprived can be viewed as less healthy. On average, the students slept a total of seven hours less over the two restricted-sleep sessions.
The team, lead by Dr Tina Sundelin, found that strangers were good at assessing how exhausted a person was, and that they rated the sleepy set of photographs as less attractive than the photos of the same people when they were well-rested. Strangers were also less likely to want to socialise with that person. "If you can see someone hasn't slept, you'll have a good idea that they might not be the best person to be around". These are small tweaks, but they can help you nab more sleep and change how the world perceives you. "We want our partners to be attractive and energetic". "The reasons for avoiding people who look sleepy may include the fact that sleepy individuals are at a higher risk for accidents, or more prone to be carriers of contagious pathogens, or aspects making them less socially rewarding to be around", the researchers explain.
It's good to know you've got options if you've had a few rough nights, but Sundelin still encourages you to prioritize getting more sleep.