Fat inside your tongue may be to blame for sleep apnea. That's the conclusion of a study that found that tongue fat is higher in people with obesity who also repeatedly stop and start breathing in their sleep.

The study, published in the American Journal of Respiratory and Critical Care Medicine, found that people can lose fat in their tongue as they drop overall body weight.

"The question then was if you reduce the fat in your tongue, does that improve your sleep apnea? And the answer from our paper is 'yes,' " said the study's lead author, Penn Medicine sleep specialist Dr. Richard Schwab.

Researchers placed 67 people with obesity and sleep apnea in a sleep study. They underwent MRI imaging to measure their airway sizes and soft tissue, tongue fat and abdominal fat volumes before and after weight loss. The weight loss was obtained either by lifestyle changes or surgical methods.

After a 10% weight loss, patients' sleep apnea scores improved by 31%. MRI images showed that the less volume the individual's tongue had after weight loss, the more their symptoms improved.

Excess weight has long been considered the most common cause of sleep apnea in adults, although this is the first study to focus specifically on the tongue. The American Sleep Apnea Association said an estimated 22 million Americans are affected by the disorder.