Stress on the job can be as detrimental to a person's health as smoking or not exercising, results of a study suggest.

The report in the May 27th issue of the British Medical Journal found that nurses whose jobs were the most demanding and who had little control over their work situation were more likely to report poor health. Having little social support at work was also found to contribute to poor health, the study found.

After four years, these women were more likely to report symptoms of anxiety and depression, have difficulty performing daily activities such as stair climbing and carrying groceries, and reported lower energy levels.

"Job stress has measurable effects on mental and physical health,'' Ichiro Kawachi, one of the study's authors, told Reuters. "These effects were comparable to the deleterious effects of smoking on decline in physical and mental health.''

The report suggests that efforts to lower job stress should focus on the job itself and not the individual, according to lead author Yawen Cheng and colleagues from Harvard University in Boston, Massachusetts.

For example, hospitals and healthcare managers can increase the amount of control in nurses' jobs by increasing flexibility of work schedules, reducing the amount of forced over-time, and increasing the amount of decision autonomy, Kawachi explained.

"If the psychosocial work environment contributes to the quality of life of the workforce...hospitals and medical practices will need to focus their strategies for health promotion on the redesign of jobs,'' the authors write.

While the findings apply mainly to female nurses, the model of job stress "is applicable across a wide range of occupations,'' Kawachi noted.

The study revealed that nurses in the highest third of job demands and the lowest third of job control reported the worst health. Those who had the most control over their jobs and felt the fewest job demands reported the best health status, researchers found.

Age, weight, smoking status, education level and alcohol intake did not appear to influence results.

The findings are based on data from more than 21,000 women who completed questionnaires on their health status, including mental health and job satisfaction. More than three quarters of these women worked as registered nurses in the US.