Impaired immune response to voluntary arm-crank ergometer exercise in patients with cervical spinal cord injury
Study design:Non-randomized study.Objective:The mechanism underlying exercise-induced argumentation of natural killer cell cytotoxic activity (NKCA) in humans remains unclear. To address this, NKCA responses were studied during and after exercise in persons with cervical spinal cord injury (CSCI) and dysfunctional sympathetic nervous system.Setting:Kibikogen Rehabilitation Center for Employment Injuries.Methods:We examined the NKCA responses to 20-min arm-crank ergometer exercise at 60% of maximum oxygen consumption in eight persons with CSCI (between C6 and C7) and six able-bodied subjects. NKCA, adrenaline, and cortisol were measured before, immediately after exercise, 1 h after exercise, and 2 h after exercise.Results:In able-bodied subjects, NKCA increased immediately after exercise (P<0.01) and then decreased to below the pre-exercise level 1 h after exercise, before recovering to the baseline level at 2 h after exercise. Plasma adrenaline concentrations increased significantly immediately after exercise (P<0.01) and returned to the baseline level 1 h after exercise. The plasma cortisol level did not change throughout the study. In contrast, NKCA, plasma concentrations of adrenaline, and cortisol did not change throughout the study in subjects with CSCI.Conclusion:In subjects with CSCI, the lack of response in NKCA throughout the experiment is probably mainly due to a dysfunctional sympathetic nervous system.