​The April issue of Pain reports a sound study examining self-perceived pain changes during walking in patients with osteoarthritis. Pain in Motion previously reported that up to 30% of osteoarthritis patients have central sensitization, and this new study from U.S. researchers suggests a role for central sensitization in explaining pain changes during daily physical activities like walking. 

Over 100 well-characterized osteoarthritis patients were studied thoroughly, examining associations between pain changes during walking and several features of the illness (including measures of central sensitization and psychological features). It was found that the levels of discomfort increased throughout the 6-minutes walking test. The researchers themselves suggest that the dysfunctional endogenous analgesia in response to exercise, as seen in some chronic pain patients like fibromyalgia and whiplash associated disorders, might account for the observed increased pain during walking. This notion is supported by their finding that temporal summation predicted the variance in pain increases during walking. Future work should examine whether endogenous analgesia during exercise is dysfunctional in osteoarthritis patients, and whether it accounts for pain increases during physical activity. 

Together, these findings call for interventions that target the problem of pain increases during physical activity. In fact, this might be a crucial factor in improving adherence to exercise and physical activity interventions in patients with osteoarthritis. Given these study findings, it seems rational to target central sensitization and cognitive-emotional factors like pain catastrophizing for ‘treating’ pain increases during physical activity. 

Further reading:

http://www.ncbi.nlm.nih.gov/pubmed/24378879

Jo Nijs