When teachers are stressed, so are their students, according to a new study.

In the report, published in the journal Social Science & Medicine, researchers assessed the burnout levels of 17 teachers of fourth through seventh grade. They also assessed levels of the stress hormone cortisol in their students—more than 400 of them—by taking saliva samples at three different times during the school day.

The researchers found that students had higher levels of cortisol if their teachers reported higher burnout levels. “Teachers who experience higher levels of burnout report to be more stressed, less effective in teaching and classroom management, less connected to their students, and less satisfied with their work,” the study authors write.

The study is the first to link teacher burnout to physical stress changes in their students. Occupational burnout has been shown to take a toll on job success and contribute to health problems; in the case of physicians who experience stress and burnout, both doctors and their patients are affected.

“Considering that classroom teachers can take on many roles for elementary school students, including mentor, role model, and parental roles, it is possible that spending most of the school day in interaction with a stressed and burned out teacher is taxing for students and can affect their physiological stress profile,” the researchers write.

Burned out teachers may also have fewer resources and support, which could also contribute to student stress. The study, however, could not definitively connect students’ cortisol levels to their teachers. More research is needed to understand how people’s stress could impact the stress levels of people around them.

This article originally appeared on Time.com.