Moderate-intensity regular exercise decreases serum tumor necrosis factor-α and HbA1c levels in healthy women

OBJECTIVE: To evaluate the effects of moderate-intensity regular exercise on serum levels of tumor necrosis factor-alpha (TNF-alpha) and glucose and lipid metabolism parameters. DESIGN: Longitudinal intervention study of a 5 month exercise training program (30-45 min/day, 4-5 days/week). SUBJECTS: Forty-one healthy Japanese women aged 41-69 y at baseline; 27 participants in the exercise program. MEASUREMENTS: Body mass index (BMI), waist-to-hip ratio (WHR), percentage body fat, and fasting levels for serum TNF-alpha, serum soluble TNF receptor p55 (TNF-RI) and TNF receptor p75 (TNF-RII), serum lipids, HbA(1c). and serum insulin before and after exercise. RESULTS: In overweight to obese subjects, serum levels of TNF-alpha, TNF-RI and TNF-RII were significantly higher than those in lean subjects. There were significant correlations between log serum TNF-alpha and BMI, percentage body fat, WHR, HbA(1c) and log insulin. TNF-RI was significantly correlated with BMI, percentage body fat, WHR and HbA(1c). TNF-RII was also associated with BMI, percentage body fat and WHR. However, the correlation between TNF-RII and HbA(1c) did not reach statistical significance. Neither TNF-RI nor TNF-RII was correlated with log insulin. In contrast, TNF-alpha, TNF-RI and TNF-RII were negatively correlated with HDL cholesterol. Regular exercise decreased BMI, percentage body fat, HbA(1c), serum TNF-alpha, TNF-RI and TNF-RII and increased HDL cholesterol levels. In addition, exercise-induced change in serum TNF-alpha was independently correlated with changes in HbA(1c) and serum insulin, after being adjusted for the change in fat-free mass. CONCLUSION: Changes in serum TNF-alpha that occur with exercise may play an important role in improving glucose metabolism parameters.