还不相信“美容觉”的神奇功效吗？

为了验证美容觉是不是真的很有效，瑞典的学者让年龄从18到31岁间的23位男性和女性每天睡足8小时，然后拍下照片，接下来的几天，让他们只睡5个小时。结果可想而知，后者的精神状态及面容气色，都远远不及前者。

 "Sleep is a cheap and effective 'beauty treatment,'" says the lead author of the study, "In fact, sleep should be seen as the body's natural beauty treatment and a preferred alternative or complement to other beauty treatments."

While that 4% decline in attractiveness may not seem like a lot, it can make a big difference in everyday life, Axelsson says. Looking healthy and well-rested "improves the chances of better treatments in a wide range of social situations," he says. "It is well known that attractive people are favorably treated in many situations."

Sleep deprivation can indeed have an impact on a person's features.
 
"People's eyes don't seem to be open quite as wide, the muscles in their face are more drawn or relaxed," the expert says. "Sleep does help restore muscle tone and repair the physiological degradation that occurs after being up for 16 hours going through your normal day."

The study findings make sense biologically, says director of the Strong Sleep Disorders Clinic, When we sleep, our perspiration "naturally moisturizes" our skin, and lying down increases "blood flow to the face, so wrinkles are going to be less apparent, at least temporarily," he says.

And the body secretes more human growth hormone (HGH) during deep sleep, which may somehow contribute to a more rested, youthful appearance.

According to the expert, potential mates may be hard-wired to respond to these subtle changes. Humans may have evolved "an ability to detect sleep-related cues" that "is likely to affect mate preferences," he says. "It has been proposed that facial cues perceived as attractive are signals of good health that have been selected evolutionary to guide mate choice and successful transmission of genes."