The effect of physical activity and physical fitness on plasma adiponectin in adults with predisposition to metabolic syndrome

The purpose of this study was to measure changes in plasma adiponectin (ApN) over 24 months of exercise intervention in middle age adults with a predisposition to metabolic syndrome and to determine if changes in ApN were more affected by physical activity or physical fitness. Thirty-six subjects completed a 24 months home-based exercise program (cycling ≥ three times per week, ≥ 45 min/session at 50–65% of VO2peak). Body composition, blood samples, and physical fitness were studied at baseline and after 12 and 24 months of participation in the study. The prescribed physical activity was monitored via self-reported exercise diary to determine MET levels, hours, and exercise compliance. Two-tailed repeated measures ANOVA and Spearman Rank Correlation Coefficients were used to detect significant differences and associations between the variables. ApN increased significantly (P < 0.05) after 12 months in males (n = 17; 5.3 ± 1.9–7.0 ± 3.0 μg ml−1) but not in females (n = 9; 8.6 ± 3.8–11.5 ± 4.0 μg ml−1). The net change in ApN over 24 months was significantly correlated to the net change in VO2peak (physical fitness) (r = 0.66; P < 0.001), whereas exercise intensity was negatively correlated to ΔApN over 12 months (r = −0.4; P ≤ 0.04) and 24 months (r = −0.45; P ≤ 0.02). Based on our results, an improvement in cardiorespiratory fitness of 15% increased plasma ApN concentration. Our findings suggest that moderate physical activity performed over many months induces positive changes in the plasma ApN concentration in adults with a predisposition to metabolic syndrome.