October 15 (HealthDay News) -- That snoring in the classroom may be from the teacher, not the students, a new study suggests.

Nearly a fourth of U.S. teachers say they are so sleep-deprived that their teaching skills are significantly impacted, according to a survey of teachers, administrators and support staff conducted by Ball State University researchers.

"Sleepy teachers are at a higher risk of providing insufficient supervision and inferior classroom instruction," researcher Denise Amschler, a Ball State health science professor, said in a university news release. "They also report more mood swings, and are at a higher risk of serious personal health problems."

The study found that about 43 percent slept an average of six hours or less each night, and 64 percent said they felt drowsy during the school day. Only a third of all school personnel said they got a good night's sleep most of the time.

The study also found female respondents tended to have sleep disturbances, drowsiness and sleep problems more often.

Long work days caused not only by grading papers and preparing assignments may be the cause. Nearly 45 percent of respondents also worked part-time jobs.

"Many teachers are forced to coach, farm, run a family business, or work a second job just to pay the bills," Amschler said. "When you factor in the responsibilities of raising a family, it is easy to see why teachers sleep so little. There is very little time."

Amschler said the study shows that more assistance is needed to reduce teacher stress and workloads through a variety of programs, including the new federally mandated wellness policies for schools.

SOURCE: Ball State University, news release, Sept. 29, 2008