The phrase "beauty rest" may have some truth to it, a new study published in the Journal of Clinical Sleep Medicine suggests.

Conducted by the researchers at the University of Michigan, the paper is the first to show specific improvements in facial appearance in individuals treated for sleep apnea.

Sleep apnea affects millions of adults and is characterized by snoring and breathing interruptions, which result in reduced quality of sleep. And while many cases go undiagnosed, a popular treatment is a system known as CPAP, which includes a mask that helps prevent snoring and thus improve daytime alertness.

Using a sensitive "face mapping" technique used by surgeons, the researchers analyzed the changes in 20 middle-aged apnea patients before and several months after they began using CPAP.

"One of the breakthroughs in plastic surgery over the last decade has been our aim to get more objective in our outcomes," Dr. Steven Buchman, a UM plastic and reconstructive surgeon, said in a statement. "The technology used in this study demonstrates the real relationship between how you look and how you really are doing, from a health perspective."

Though the research has yet to be confirmed by larger studies, the results pointed toward a number of objective changes typically perceived as improvements in one's appearance.

For example, patients' foreheads were less puffy and faces less red after CPAP treatment, the study showed. The researchers also discovered a reduction in forehead wrinkles after treatment.

What they did not see was a change in facial characteristics often associated with fatigue.

"We were surprised that our approach could not document any improvement, after treatment, in tendency to have dark blue circles or puffiness under the eyes," said Dr. Ronald Chervin, director of the UM Sleep Disorders Center and lead study author.

Chervin says he hopes to continue to study the effects of sleep apnea treatment on a wide assortment of aspects of a person's life.

"We want sleep to be on people's minds, and to educate them about the importance of getting enough sleep and getting attention for sleep disorders."