Circulating Leukocyte Levels In Response To Active And Passive Cycling In Able Bodied And Spinal Cord Injured

Abstract

2089 Individuals with spinal cord injury (SCI) lack complete neuroendocrine responses that may influence exercise-induced alterations in immune cell responses. PURPOSE: To examine exercise-induced circulating leukocyte and leukocyte subset responses in individuals with SCI and in able bodied age-matched controls (AB). METHODS: Seven subjects with SCI (3 paraplegic- SCI-PP & 4 quadriplegic-SCI-QP) and seven age-matched AB controls completed 30 min of either active and/or passive cycling. SCI-PP completed 30 min of upper body assisted leg cycling (UBALC) (30 min @ 70% VO2peak) and 30 min of passive leg cycling. SCI-QP completed 30 min of passive leg cycling and 30 min of combined passive arm and leg cycling. AB completed 30 min of active and passive leg cycling. Blood samples were taken before (pre-EXR), after (post-EXR), 2hr post, and 24hr post exercise. Sample analysis included leukocyte total and subset counts. RESULTS: Both active and passive exercise produced alterations in circulating leukocytes and their subsets in all groups that were studied. In SCI-PP, total leukocyte post-EXR UBALC and passive responses were greater (p<0.05) than pre-EXR (14.66 + 4.6 and 8.46 + 1.6 vs. 7.06 + .81 and 6.46 + 1.2 cells x106/ml, respectively). In SCI-QP, passive leg (8.09+1.7 cells x106/ml) and combined arm and leg (12.03 + 1.4 cells x106/ml) cycling produced elevations in total leukocytes compared to pre-EXR with the latter being significantly greater. In AB, active cycling (post-EXR = 9.20+1.8 vs. pre-EXR = 5.14+1.5 cells x106/ml) produced significant elevations, but passive cycling did not (post-EXR = 6.55+1.9 vs. pre-EXR = 5.49+.13 cells x106/ml).group. CONCLUSION: These data indicate that both passive and active exercise produce elevations in circulating leukocytes in individuals with SCI; however, passive responses are blunted. In the SCI-QP group, combined passive arm and leg cycling produced greater elevations than leg cycling alone.