Sleep apnoea is a potential health risk for millions of Americans, and a new study points to a possible culprit behind the disorder: a "fat" tongue.
Increased fat deposits
"This is the first study to show that fat deposits are increased in the tongue of obese patients with obstructive sleep apnoea," study senior author Dr. Richard Schwab, co-director of the Sleep Centre at the University of Pennsylvania Medical Centre, said in a news release from Sleep.
Sleep apnoea is a common disorder in which the airways constrict during sleep, leading to repeated stops and starts in breathing. The telltale signs include chronic loud snoring, with periodic gasps or choking – and, for many people, daytime drowsiness because of poor sleep.
Read: Sleep apnoea
But the effects go beyond fatigue. Studies suggest those pauses in breathing stress the nervous system, boosting blood pressure and inflammation in the arteries.
Obese people tend to be at higher risk for sleep apnoea, and Schwab's team say the new findings may help explain the link between obesity and the breathing disorder.
The study included 90 obese adults with sleep apnoea and 90 obese adults without the disorder.
Concentrated at the base of the tongue
The participants with sleep apnoea had significantly larger tongues, tongue fat and percentage of tongue fat than those without sleep apnoea, the researchers found. The tongue fat in the people with sleep apnoea was concentrated at the base of the tongue.
In addition to increasing the size of the tongue, higher levels of tongue fat may prevent muscles that attach the tongue to bone from positioning the tongue away from the airway during sleep, Schwab's group explained.
While the study found an association between tongue fat content and sleep apnoea, it could not prove cause and effect.
Read: Dealing with sleep apnoea
However, the researchers believe future studies should assess whether removing tongue fat through weight loss, upper airway exercises or surgery could help treat sleep apnoea.
"Tongue size is one of the physical features that should be evaluated by a physician when screening obese patients to determine their risk for obstructive sleep apnoea," American Academy of Sleep Medicine President Dr. Timothy Morgenthaler added in the news release.
"Effective identification and treatment of sleep apnoea is essential to optimally manage other conditions associated with this chronic disease, including high blood pressure, heart disease, type 2 diabetes, stroke and depression," he said.
Nearly 35 percent of U.S. adults – 78.6 million people – are obese, according to the U.S. Centres for Disease Control and Prevention.
Sleep apnoea? Lose weight
Link between depression and sleep apnoea
Implants improve sleep apnoea
Image: Fat man yawning from Shutterstock