Low-grade systemic inflammation and leptin levels were improved by arm cranking exercise in adults with chronic spinal cord injury

Abstract

Objective: To ascertain the effect of arm cranking exercise on improving plasma levels of inflammatory cytokines and adipokines in untrained adults with chronic spinal cord injury (SCI).

Design: Longitudinal study.

Setting: Community-based supervised intervention.

Participants: Men (N=17) with complete SCI at or below T5 volunteered for this study. Participants were randomly allocated to the intervention (n=9) or control group (n=8) using a concealed method.

Intervention: A 12-week arm cranking exercise program of 3 sessions per week consisted of warm-up (10-15min), arm crank (20-30min; increasing 2min and 30s every 3wk) at a moderate work intensity of 50% to 65% of heart rate reserve (starting at 50% and increasing 5% every 3wk), and cool-down (5-10min).

Main outcome measures: Plasma levels of leptin, adiponectin, plasminogen activator inhibitor-1, tumor necrosis factor-alpha, and interleukin-6 were determined. Furthermore, physical fitness (maximum oxygen consumption [V˙O2max]) and body composition (anthropometric index, waist circumference, and body mass index) were also assessed.

Results: Plasma levels of leptin, tumor necrosis factor-alpha, and interleukin-6 were significantly decreased after the completion of the training program. Similarly, the anthropometric index and waist circumference were diminished too. A moderate correlation was found between leptin and the anthropometric index. Finally, V˙O2max was significantly increased, suggesting an improvement of physical fitness in the intervention group. No changes were found in the control group.

Conclusions: Arm cranking exercise improved low-grade systemic inflammation by decreasing plasma levels of inflammatory cytokines. Furthermore, it also reduced plasma leptin levels. Long-term, well-conducted studies are still required to determine whether these changes may improve clinical outcomes of adults with chronic SCI.

Keywords: AI; BMI; Exercise; IL-6; PAI-1; Rehabilitation; SCI; Spinal cord injuries; TNF-α; WC; anthropometric index; body mass index; interleukin-6; maximum oxygen consumption; o(2)max; plasminogen activator inhibitor-1; spinal cord injury; tumor necrosis factor-alpha; waist circumference.