It may be one of the greatest counter-intuitive therapies ever: older people can lower their pain perception and block responses to painful stimuli by engaging in more physical activity, not less.
A study out of Indiana University–Purdue University Indianapolis tracked 51 healthy adults, aged 60 to 77. The test subjects all wore an activity monitor device for one week to measure their level of physical activity. At week's end they underwent two tests of pain modulation—functions affecting the way pain is interpreted and perceived by the central nervous system.
One test was called "temporal summation" and measured the production of pain responses to repeated pain stimuli. The other test was called "conditioned pain modulation" and gauged the reduction of pain responses to competing pain stimuli.
The data from both tests indicate that pain modulation was meaningfully related to daily physical activity level. Frequent moderate-to-vigorous physical activity of the test subjected to lower pain scores on the temporal summation test—indicating less pain facilitation. The participants who did more light physical activity or had less sedentary time per day had lower pain scores on the conditioned pain modulation test—indicating better pain inhibition.
That is to say, older adults who did more moderate to vigorous physical activity perceived pain less, while those who did at least some activity were better able to block pain perceptions. The researchers believe these differences to be relevant to the "central sensitization" process believed to be responsible for the transition from acute to chronic pain – the more active you remain, the less likely you will be wracked with constant aches in pain as you grow older.
"Our data suggest that low levels of sedentary behavior and greater light physical activity may be critical in maintaining effective endogenous pain inhibitory function in older adults," said lead author Kelly M. Naugle, PhD. It was the first study to provide objective evidence suggesting that physical activity behavior is related to the functioning of the endogenous pain modulatory systems in older adults.
Next steps? Research into matching certain types of exercise with specific pain modulation, with an eye towards prescribing types of physical activity that can best improve pain response pattersns.
The research was published in PAIN®, the official publication of the International Association for the Study of Pain.