Do you have an unchallenging job with little control over what you do? You may be more likely to be a couch potato in your leisure time, a new study shows.

These characteristics of the job spill over into their non-working life, says Dr. David Gimeno of University College London, one of the researchers on the study.

Gimeno and his colleagues looked at how working in passive jobs-where the worker has little stress and little control-affected leisure time activity by looking at 4,291 male and 1,794 female British civil servants, who ranged in age from 35 to 55. Over a five-year period, the study participants were categorized at three different time points based on how passive their jobs were and their amount of leisure-time physical activity.

Job passivity didn't influence how active women were outside work. But men who were in passive jobs at all three time points were 16 percent more likely to have low levels of leisure time physical activity than men who had never worked in a passive job.

These are very small effects, Gimeno said in an interview. Nevertheless, he added, they are likely to affect many, many people-resulting in a large health impact for society as a whole.

Given the health risks of a sedentary lifestyle, he and his colleagues note in Occupational and Environmental Medicine, upstream interventions that reduce dull, demotivating and unchallenging jobs may be worthy of consideration.

Evidence on how the nature of a person's job affects his or her leisure-time physical activity has been mixed, Gimeno and his team note, and research has not looked at how a person's job characteristics over time might affect their lifestyle.

We need to consider what type of jobs we are creating, the researcher added. That doesn't mean that everyone needs to be an artist.

But, Gimeno said, it does mean that people should have opportunities to develop on the job, gain knowledge, and increase their skills. You need people not only to be like machines and only do the work, but also to grow in the work.

SOURCE: Occupational and Environmental Medicine, November 2009.