Study leader Dr. Ronald Chervin, director of the University of Michigan's Sleep Disorders Center, said sleep apnea affects millions of adults -- most undiagnosed -- and puts them at higher risk for heart-related problems and daytime accidents.
The researchers used a sensitive "face mapping" technique usually used by surgeons, and a panel of independent appearance raters, to detect changes in 20 middle-aged apnea patients just a few months after they began using a system called CPAP to help them breathe better during sleep and overcome chronic sleepiness.
CPAP users must wear a breathing mask in bed while sleeping. CPAP is known to stop snoring, improve daytime alertness and reduce blood pressure, Chervin said.
The research needs to be confirmed by larger studies, but the findings might eventually give apnea patients even more reason to stick with CPAP treatment, Chervin said.
"The common lore, that people 'look sleepy' because they are sleepy, and that they have puffy eyes with dark circles under them, drives people to spend untold dollars on home remedies," Chervin said.
"We perceived that our CPAP patients often looked better, or reported that they'd been told they looked better, after treatment. But no one has ever actually studied this."
The study was published in the Journal of Clinical Sleep Medicine.
Notable deaths of 2014 [PHOTOS]