A new study has found evidence to suggest that obese people may be more susceptible to pain than others.
Researchers at Ohio State University examined responses to electrical stimulation of the ankles in a number of older people suffering from osteoarthritis of the knee, before and after training in muscle relaxation techniques.
The study discovered that obese participants displayed a noticeably greater physical response to the stimulus, both before and after the training.
Moreover, this was identified in spite of the obese subjects reporting in questionnaires that they felt no more pain than the other participants.
The study's principal author, Charles Emery, stated: "Our tests showed both groups had higher physical pain thresholds after the relaxation session. But the obese participants still had a lower threshold for tolerating the pain.
"This is important because if an obese person begins an exercise program, he may not cognitively experience pain when in fact it is hurting the body on some level."
The electrical shocks were delivered by direct stimulation of the sural nerve, which runs along the ankle and calf.
Response was measured by tracking the level of reflex reaction to the stimulus in the leg muscles surrounding the nerve.
"This kind of evaluation is in some ways a more objective way of measuring the bodys response to pain, as opposed to simply asking someone if they feel pain", Professor Emery explained.