As adults age, they all experience a natural loss of muscle mass and function. A new study finds that as the loss of muscle and function in the throat occurs it becomes more difficult for efficient constriction to occur while swallowing—which leads to an increased chance of food and liquids being left over in the throat.

The study, published in Dysphagia by Sonja M. Molfenter, an assistant professor of communicative sciences and disorders at New York University’s Steinhardt School of Culture, Education, and Human Development, and her colleagues, helps to explain why 15% of seniors’ experience dysphagia, or difficulty swallowing.

Among other health issues, swallowing difficulties can lead to malnutrition, dehydration and pneumonia—from food and drinks being misdirected into the lungs. Swallowing difficulties can also have a financial impact. Other studies have demonstrated that when patients with dysphagia are admitted to the hospital, they normally experience a 40% longer length-of-stay than those without dysphagia—estimated to cost $547,000,000 per year.

Molfenter and her colleagues noted that dysphagia in older adults is particularly relevant as the proportion of seniors in the United States is projected to increase to over 20% by 2030.

“Dysphagia has serious consequences for health and quality of life,” said Molfenter, the study’s lead author. “This research establishes the need for exercise programs for older adults that target throat muscles just like those that target the muscles of the arms, legs and other parts of the human body.”

Charles Lenell also of NYU and Cathy L. Lazarus of Mount Sinai Beth Israel and Icahn School of Medicine at Mount Sinai contributed to this study.

The study was funded by the National Institute on Deafness and Other Communication Disorders, part of the National Institutes of Health (NIH).