WEDNESDAY, March 1, 2006 (HealthDay News) -- Obese people may be more sensitive to pain than people who aren't overweight, a new study suggests.
Researchers gauged reaction to pain among 62 older adults who had osteoarthritis of the knee, a disease that affects more than 20 million people in the United States. The study participants -- one-third of whom were obese -- were given a mild electrical shock on the left ankle that caused sensations of tingling and mild pain in the lower leg. This was done before and after the participants took a 45-minute, coping-skills session that included progressive muscle-relaxation exercises.
The researchers wanted to see if coping-skills training would help people with osteoarthritis to better cope with the pain caused by the disease.
But the scientists were especially interested in determining how the obese group responded to pain. A small number of studies have looked at pain sensitivity among obese people, but they have produced conflicting results.
The researchers found that obese individuals had a greater physical response to the electrical stimulation than non-obese people. They based their findings by measuring the reflex of the lower leg muscles; this indicated that the obese individuals had a lower tolerance for pain, even though they said that they felt no more pain than non-obese people.
The findings are to be presented Saturday at the American Psychosomatic Society annual meeting, in Denver.
"For subjective indicators of pain, obese people indicated similar levels of pain to non-obese people," said study author Charles Emery, a professor of psychology at Ohio State University. "But when we looked at objective indicators, we found that the obese group had a lower threshold for pain."
Emery believes that obese people may have more experience with pain because of their weight. "They may be used to some degree of pain," he said.
But obese people appear to experience greater pain than non-obese people, Emery added. "It is important to look at both objective indicators of pain, as well as subjective indicators," he said. "We need to keep in mind that the subjective rating may not be reflective of physiological processes that are going on."
One expert found the study results compatible with what is known about how people experience pain.
"These results do not surprise me at all," said Dr. Doris K. Cope, director of the Pain Medicine Division at the University of Pittsburgh.
Pain is not only a physiological stimulus-response, but the psychological interpretation of that stimulus providing a total experience of pain, Cope said. "Psychological studies of the obese demonstrate personality differences between obese and non-obese subjects, so it would not surprise me if these patients also experience pain differently as well," she said.
More information
The American Society of Anesthesiologists can tell you more about managing pain.
