Burnout is a growing problem among American doctors, a new study indicates.

Analyzing the results of 2011 and 2014 surveys of more than 6,000 doctors across the United States, researchers found that the number who met the criteria for burnout rose from 45 percent to 54 percent over that time.

Burnout rates rose in nearly all specialties, but the highest rates of burnout were among those in general internal medicine, family medicine and emergency medicine. There was no increase in work hours or in rates of depression among doctors.

Doctors' satisfaction with work-life balance fell between the two surveys, according to the study, which was published Dec. 1 in the journal Mayo Clinic Proceedings and conducted by Mayo Clinic researchers in partnership with the American Medical Association.

"Burnout manifests as emotional exhaustion, loss of meaning in work, and feelings of ineffectiveness," study author Dr. Tait Shanafelt said in a Mayo news release. "What we found is that more physicians in almost every specialty are feeling this way, and that's not good for them, their families, the medical profession or patients."

Research has shown that doctor burnout can lead to poor patient care, higher doctor turnover and a decrease in the overall quality of the health care system.

The study authors said there are a number of ways health care organizations can help reduce doctors' risk of burnout, including giving doctors greater flexibility and control over work.