The effect of acute and chronic exercise on inflammatory markers in SCI

A spinal cord injury (SCI) is associated with an increased prevalence of physical inactivity and obesity, conditions linked to illnesses with inflammatory etiology, such as diabetes or cardiovascular disease. This may at least partly explain the elevated inflammatory risk marker profile and the higher occurrence of the associated diseases found in individuals with SCI. In able-bodied populations, exercise helps to improve this risk marker profile prompting the question whether exercise can mitigate some of the SCI related risk through acute disturbances of the inflammatory environment. Despite a smaller active muscle mass during upper body activities, a similar acute inflammatory response has been observed with this modality when compared with lower body exercise. This supports the use of upper body exercise interventions to combat disease linked to inflammation in individuals not able to participate in other exercise activities. However, more dramatic reductions in active muscle mass and/or sympathetic dysfunction found in those with cervical SCI can result in an absent or blunted acute inflammatory response. Nonetheless, intervention strategies like exercise, functional electrical stimulation or passive elevation of core temperature induce some modest positive acute responses even in individuals with high level SCI. The evidence base for chronic interventions is small but suggests that long term exercise can indeed improve the inflammatory risk marker profile in individuals with thoracic and, to a lesser extent, with cervical SCI. Future challenges include defining disability-specific minimal exercise or temperature stimuli required to induce meaningful chronic changes in inflammatory markers.