Grant: Project Grant

Approximately 20 % of the Canadian population is currently living with chronic pain, which is defined as pain that lasts for more than 6 months. Amongst chronic pain syndromes, low back pain is the most prevalent. Unfortunately, current treatments only have relatively modest effects on pain. Fortunately, one intervention that stands out is physical exercise. Indeed, physical exercise has been repeatedly shown to reduce chronic pain. However, little is know of the mechanisms by which physical exercise influences chronic pain. The objective of the proposed project is to examine the cerebral mechanisms mediating the effects of physical exercise on chronic low back pain (CLBP). Whereas the spine of most patients (~85%) with low back pain does not show any particular signs of pain-related pathology, CLBP has been associated with alterations in the structure and function of the hippocampus, a brain region important for controlling stress. Studies in animals suggest that the release of pro-inflammatory molecules in the bloodstream as a result of the constant pain may cause the hippocampal deficits observed when pain become chronic. Interestingly, physical exercise has been shown to have effects on both inflammation and hippocampal structure, suggesting that it may impact chronic pain by reducing inflammation and restoring hippocampal structure and function. In order to test our hypotheses, 100 patients with chronic low back pain and a 100 healthy controls will be randomly assigned to a 12-week long physical exercise training program, or to a wait-list control condition. During the weeks immediately preceding and following the 12-week study period, participants will have their brain scanned with magnetic resonance imaging, and their blood will be analyzed for signs of inflammation. We expect that the results of this unique multi-disciplinary study will provide unprecedented insight into the cerebral mechanisms underlying CLBP and its relief through physical exercise.