Recent research reveals that on-the-job stress leads not only to burnout but also an increase in the rates of heart disease, Type 2 diabetes, flu virus, high blood pressure and metabolic syndrome.

One study showed stress can negate the heart-healthy aspect of a physically active job, leading to thicker arteries in physically active and stressed workers compared to active, non-stressed employees.

The results show that burnout may boost the risk of illness by a "magnitude similar to other risk factors, such as high body mass index, smoking and lack of physical exercise," said study lead author Samuel Melamed of Tel Aviv University in Israel.

A new study of 677 workers in Israel revealed those who suffered job burnout were 1.8 times more likely to develop Type 2 diabetes. In Type 2 diabetes a person's body becomes resistant to the sugar-regulating hormone called insulin. The results held even when factors like age, sex, exercise and obesity were taken into account.

Some studies have found stress can cause poor eating habits and the consumption of more alcohol, both of which can lead to health problems. Researchers in the new study suggest stress can disrupt the body's ability to process glucose, which leads to diabetes.

The scientists studied apparently healthy Israeli workers from 1998 to 2003. Nearly 77 percent of the workers were men, with an average age of 43 years. The subjects had a range of occupations, which the scientists divided into five categories: senior management, middle management or supervisory jobs -- like engineers, teachers and computer workers -- nonprofessional and self-employed persons.

A questionnaire showed about half of the 677 subjects experienced high burnout. Of the workers, 17 developed Type 2 diabetes during the study period, with 3.2 percent of burned-out workers becoming diabetic compared with 1.8 percent of the other workers.

To decide if diabetes was affected by blood pressure, the researchers examined a subset of the subjects -- 507 workers -- for which they had tested for blood pressure. The burned-out workers showed lower blood pressure levels, indicating that it was not hypertension -- high blood pressure -- causing diabetes.

An alternative explanation could be that stress triggers a spike in fatty acids in the blood and a drop in the "good" cholesterol, HDL -- both factors associated with diabetes.

The job burnout may be only part of the picture, Melamed said.

"It is possible that these people are prone to diabetes because they can't handle stress very well," he said. "Their coping resources may have been depleted not only due to job stress but also life stresses, such as stressful life events and daily hassles."

Stress in general can disrupt the body's ability to process glucose, especially in people whose genetics make them vulnerable, said Richard Surwit of the Duke University Medical Center.

Surwit, who was not involved in the study, said the results should be replicated in a much larger group of subjects to see if the same results prevail.

Job burnout can lead to a combination of three symptoms: emotional exhaustion; physical fatigue or exhaustion; and cognitive weariness (slow thinking).

This state differs from a temporary malaise that passes after a period of rest. Causes of burnout include chronic stresses, such as lack of rewards, job insecurity, regular physical abuse and sexual harassment, as well as daily hassles and sudden traumas.

The scientists suggest, in the November/December issue of the journal Psychosomatic Medicine, that the results confirm the need for effective interventions to reduce stress before it becomes burnout.