The new evidence supports the possibility that obesity and physical inactivity play a role in a person's risk of developing chronic pain in those areas, said study co-author Dr. Paul Mork, of Norwegian University of Science and Technology.

Mork and colleagues followed more than 30,000 adults who participated in a large Norwegian health study. They recorded participants' body mass index (BMI) - a measure of weight related to height - at the start of the study, as well as how often they exercised, and then tracked them over the next 11 years.

Overall, 1 of every 10 people in the study developed lower back pain, and nearly 2 of every 10 developed shoulder or neck pain.

After taking into account participants' age, BMI, whether or not they smoked, and whether they did manual labor at work,

the research team found that men who were exercising 2 hours or more per week at the start of the study were 25 percent less likely to have lower back pain 11 years later, and 20 percent less like to have neck or shoulder pain, compared men who didn't exercise at all. And women who exercised at least 2 hours per week were 8 percent less likely to develop lower back pain than women who were inactive, and 9 percent less likely to develop neck and shoulder pain.

Weight, not surprisingly, also affected the risk of chronic pain later on. Obese men were almost 21 percent more likely to develop chronic lower back pain than men of normal weight, and 22 percent more likely to develop neck or shoulder pain. Obese women were also 21 percent more likely to develop lower back pain than women of normal weight, and 19 percent more likely to develop neck and shoulder pain.

Based on the results, Mork believes that even moderate physical exercise - just one hour or more per week - "can, to some extent, compensate for the adverse effect of being overweight and obese on future risk of chronic pain."