Female teachers are more likely to develop vocal problems than male teachers.
The researchers - led by Eric Hunter of the Department of Communicative Sciences and Disorders at Michigan State University - recently presented their findings at the Acoustical Society of America Spring 2016 Meeting in Salt Lake City, UT.
Hoarseness, vocal tiredness, aching of neck muscles, and loss of voice are all symptoms of vocal fatigue, which is often caused by excessive vocal activity.
According to the research team, vocal fatigue is a common occurrence among teachers. Research has shown that, compared with people in other professions, teachers are twice as likely to develop voice problems.
What is more, vocal fatigue tends to be more common among female teachers than male teachers.
"Females teachers are particularly at risk of developing voice problems, affecting teaching quality and leading to increased teacher absenteeism, increased healthcare costs and sometimes even early retirement," says Hunter. "Teachers' voice disorders also hamper students' learning, especially for those students with learning or hearing difficulties."
Previous research has indicated that gender differences in the laryngeal system, endocrine system, and lung usage may play a role in the higher risk of vocal problems among female teachers.
Now, Hunter and colleagues say it could be down to differences in lung function.
Reduced lung function for female teachers with vocal fatigue symptoms
To reach their findings, the team enrolled 122 elementary and middle school teachers, of whom 96 were female and 26 were male.
Symptoms of vocal fatigue among the teachers were assessed using a standardized survey known as the Vocal Fatigue Index (VFI).
All teachers underwent a test with a spirometer, a device that assesses lung function by measuring how much air a person inhales and how quickly a person exhales.
The researchers then compared the teachers' VFI scores with the results of their spirometry tests.
The team found that female teachers who had more symptoms of vocal fatigue had reduced lung function. No such association was found among male teachers.
"Our study is the first to connect voice fatigue problems with gender-based physiological differences in lung functions, pointing to respiratory function as a source of the gender inequality in voice problems."
Spirometry could offer a simple, low-cost test for vocal fatigue
The researchers say their findings suggest that spirometry could offer a simple, low-cost clinical test for vocal fatigue - a condition that is often tricky to identify, since the vocal cords of many individuals often look normal during examination.
Furthermore, spirometry could be used to screen teachers for vocal fatigue, according to the researchers.
They note that a reduction in lung function - identified through spirometry - could warn teachers of their possible risk of voice problems, enabling them to take preventive measures, such as vocal exercises.
Spirometry may also allow more personalized treatment for patients with voice problems, something the team says has been lacking.
Next, Hunter and colleagues plan to investigate how stress, hormonal changes, age, and other factors affect vocal health among teachers.