Internet-delivered lifestyle physical activity intervention: limited inflammation and antioxidant capacity efficacy in overweight adults.

Overweight and physical inactivity are associated with elevated reactive oxygen species and chronic low-grade inflammation. Exercise training studies have measured changes in systemic inflammatory and oxidative/antioxidative biomarkers but predominantly at moderate-high intensities. Few low-intensity, lifestyle-based physical activity (PA) studies have been conducted. The purpose of this study was to determine whether improvements in lifestyle-oriented PA resulting from a 16-wk Internet-delivered PA program [Active Living Every Day-Internet (ALED-I)] elicit cardioprotective improvements in measures of inflammation, oxidation, or antioxidant enzyme capacity. Forty-one men and women (age 23-62 yr) were randomized to either the ALED-I intervention [n = 19; age = 40.4 +/- 1.9 yr; body mass index (BMI) = 31.4 +/- 1.1 kg/m(2)] or a delayed intent-to-treat control condition (n = 22; age = 46.6 +/- 1.3 yr; BMI = 31.0 +/- 0.7 kg/m(2)). TNF-alpha, C-reactive protein, myeloperoxidase, superoxide dismutase, catalase, total antioxidative capacity, change in PA, and other cardiometabolic disease risk factors were measured at baseline and postintervention. The ALED-I group increased PA and decreased central adiposity without changes in the control group. There was no change in the control group for any inflammation, oxidation, or antioxidant biomarkers. TNF-alpha decreased (P = 0.01) in the intervention group but was not statistically different from the control group. In conclusion, modest improvements in daily low-intensity ambulatory PA as a result of an Internet-delivered lifestyle PA intervention may be cardioprotective in sedentary and overweight adults through reductions in central adiposity and inflammation. However, the absence of favorable changes in other inflammation, oxidation, and antioxidant biomarkers highlights the need for further attention to the dose response of lifestyle-structured PA promotion strategies for health maintenance/improvement.